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21
Ecological
Effects of
Forest Fires
.A72
no.1133
letin No. 1133
MARC: 1956
U.S . DEPARTMENT OF AGRICULTURE
ACKNOWLEDGMENTS
Throughout the course of the investigations reported here,
R. R. Robinson, Area Forester, Bureau of Land Management, U. S.
Department of the Interior, was very cooperative. He and his
staff assisted greatly in the successful completion of the studies,
Officials of the Fish and Wildlife Service, U. S. Department of the
Interior, also were very helpful. The University of Alaska
generously furnished office space and living quarters during the
time the author was completing the report.
Various specialists identified . the plants collected in Alaska.
Special recognition is given to their assistance, as follows: William
A. Dayton, U. S. Forest Service-in charge of identification of the
higher plants; Elbert L. Little-trees; Doris W. Hayd-most of
the herbaceous plants except grasses; Carleton R. Ball (retired),
U. S. Department of Agriculture-willows; Jason R. Swallen,
Head Curator, U. S. National Herbarium-grasses; William C.
Steere, Professor of. Botany, Stanford University-bryophytes;
Alexander W. Evans, Emeritus Professor of Botany, Yale Uni-
versity-Cladoniae; John W. Thomson, Jr., Associate Professor of
Bot~ny, University of Wisconsin-various groups of lichens; and
I. MacKenzie Lamb, National Museum ~f Canada-Stereocaula.
I
CONTENTS
Page Page
Introduction____________________ 1 Effect of fire on soils-Continued
Interior of Alaska_______________ 3 Sqil productivity______________ 78
Geography___________________ 3 Effect of fire on hydrologic relations_ 78
Climate______________________ 3 Effect of fire on animalpopulations_ 79
Forests_______________________ 5 Fur-bearing animals___________ 81
History of forest fires in interior · Moose_______________________ 82
Alaska_______________________ 9 Caribou______________________ 85
Effect of fire on forests___________ 18 Effect of fire on economic develop-
Trees________________________ 18 ment________________________ 87
Subordinate forest vegetation___ 26 Summary and conclusions________ 90
Succession after fire____________ 31 Literature cited_________________ 95
Effect of fire on soils_____________ 71 Appendix_______________________ 104
Humus layers_________________ 73 Check list of plant species col-
Physical properties____________ 74 lected__ ___ _ _ _ _ __ __ __ _ _ _ _ _ _ _ 104
Chemical properties___________ 77 Soil analyses __________________ 116
II
ECOLOGICAL EFFECTS OF FOREST FIRES
IN THE INTERIOR OF ALASKA 1
~y H. 1. ~JIIZ 2
Alaska Forest Research Center, Forest Service
INTRODUCTION
The area of Alaska is approximately 586,400 square miles (375,296,-
000 acres), including both land and water surfaces. Actual land area
is approximately 572,555 square miles (366,435,000 acres). About 60
percent of the land area, or 219,861,000 acres, is in the interior.3 In
this vast area tree growth is the dominant vegetation on most of the
land below an altitude of about 2,500 feet. However, in flat exces-
sively wet lowlands, variously designated as muskeg, tundra, or bog,
tree growth is absent or very scanty. Nearly 120 million acres bear
sufficient tree growth to warrant designation as forest land. ·This
great, predominantly coniferous, forest is analogous to the 'taiga of
Siberia; its ecological counterpart is found throughout the boreal
forest of northern Canada, the Scandinavian countries, and northern
Russia. It represents a tremendous potential source of cellulose.
The forests of interior Alaska, as is true of all forests of the far
north, are very susceptible to destruction by fire. Low precipitation,
long hours of sunshine during the summer period, highly flammable
ground cover, and coniferous forests, combine to make a high fire
hazard. Most of the fires in the past were caused by man, who, in
many parts of the north, tended to live a seminomadic life. Modern
man appears to be even less careful with fire in Alaskan forests and as
his numbers increase forest fires also increase. In addition, the forests
of Alaska have also been subjected to fires caused by lightning. Once
started, fires may burn for weeks or months, spreading over hundreds
of thousands or even millions of acres. The reasons for the extensive
spread of fires are numerous, among which may be mentioned lack of
early detection, absence of effective natural barriers to spread, highly
flammable fuel, inaccessibility, and insufficient man-power and
equipment.
The study reported here, was undertaken during the summers of
_ 1949 to 1952 to provide a better understanding of the ecological effects
,f forest fires in the Alaska interior. The information sought related
o 1rimarily to the effects of forest fires on vegetation, but effects on
-.::t co
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t Submitted for publication May 13, 1955. 1 2 The author, Professor of ~ilviculture, Yale University School of Forestry, was
mployed by the Forest ServiCe to carry ·out the study. It was sponsored jointly
'Y the Forest Service, U. S. Department of Agriculture, and the Bureau of Land
T"" vianagement, U. S. Department of the Interior. The research was conducted
0 mder.the supervision of R. F. Taylor, Forester in Charge, Alaska Forest Research 0 Jenter.
1.0 3 See section on geography of the Alaska interior. I.C) ,.....
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1
2 'l'ECHNICAL BULLE'l'IN 11 3 3, U. S. DEPT. OF AGRICUL'rURE
soils, fur-bearers, big game, and to some extent on hydrology were
studied also. Field work extended from the Kenai Peninsula on the
south to the Yukon River Valley on the north (fig. 1).
Sample plots (usually 1/10 acre) and milacre quadrats were used to
obtain information on species composition, size and age relations,
density of cover, and successional trends in the various plant com-
munities illustrative of the different stages of development following
fires. Limited numbers of soil samples were collected and analyzed.
These were obtained from recently burned areas and otherwise
comparable areas long unburned. Tree stands were evaluated on 1/10-
acre plots by tallying all trees 6 or more feet in height by diameter and
height classes, and noting density of coverage for each height class or
layer. At least five trees on each plot were measured for diameter and
total height, and increment borings were obtained to establish age and
rate of growth. Stand ages in the text and tables were determined at
breast height. Most of the data were quantitative, but were supple-
mented by qualitative observations on succession, browsing by
animals, fire history, and site conditions. Subordinate vegetation,
including mosses and lichens, and tree seedlings, was investigated on
milacre quadrats. Individual species were tallied by size classes and
density of cover. Comprehensive collections of all plants, including
mosses and lichens, were submitted to specialists for identification.
These collections included 375 species of higher plants, 4liverworts, 70
mosses, and 107 lichens. All together, data on 103 sample plots, 11
transects, and 860 milacre quadrats were recorded and analyzed.
ALASKA
'!m?J GENERAL l..OCATION
OF STUDY AREAS
50 100 I~
FIGURE 1.-Map showing location of study areas.
ECOLOGICAL EFFECTS OF FOREST :FIRES IN ALAS:KA 3
INTERIOR OF ALASKA
The region referred to in this report as the Alaska interior includes
all, or nearly all, the area within the commercial range of white spruce 4
in Alaska. It embraces the vast country between the Brooks Range
on the north and the Coastal Range, bordering the Pacific Ocean on
the south. Two major divisions may be recognized, one south of the
Alaska Range and the other north.
Geography
The Alaska Range, which sweeps northeasterly in a great crescent
from the vicinity of Lake Clark on the west to the St. Elias Range on
the east, forms the watershed between the Pacific drainage on the south
and east and the Kuskokwim and Yukon Rivers on the west and north.
It is 50 to 60 miles wide with many peaks exceeding 15,000 feet eleva-
tion and with extensive glaciers and snow fields. Mount McKinley,
in the northwestern part of the great arc, with an elevation of 20,300
feet, is the highest mountain in North America.
· Theregion between the Alaska Range and the mountains along the
coast consists principally of the valleys of the Susitna, Matanuska,
and Copper Rivers, and their tributaries. All these rivers, fed by
glacial melt water, are choked with sediment.
The country north of the Alaska Range and south of the Brooks
Range includes chiefly the valleys of the Kuskokwim, Yukon, and
Tanana Rivers, and their tributaries. Mention may also be made of
the Kobuk and Noatak Rivers, both of which drain into the Arctic
Ocean. Brooks (20) 5 has described the Yukon and Kuskokwim
province as a rolling upland "deeply dissected by well-developed
drainage systems, with stream valleys and broad lowlands, and
diversified by scattered mountain masses and isolated peaks that rise
above the general level." In their courses through lowland areas the
large rivers of the interior meander through numerous channels.
With few exceptions they are heavily laden with silt derived from
glaciers and from bank cutting.
Information on transportation and communication facilities,
population and cities and towns may be found in Mid-Century Alaska,
published by the Office of Territories, U.S. Department of the Interior
in 1951 (161).
Climate
The interior of Alaska has a continental climate with great extremes
of temperature (table 1). During the winter much of the interior is
characterized by relatively high atmospheric pressure and fair, cold
weather. Aleutian low pressure systems may, however, move in over
the Yukon Valley accompanied by southerly winds, moderated
temperatures, and precipitation. Fair and unusually cold weather,
with northerly winds, results when the Arctic p.igh pressure system
builds up. In the summer the great land mass ef the interior heats up
under the influence of the long days of high latitudes, and low atmos-
4 For scientific names of Alaskan trees see Check List of Plant Species Collected,
p. 104. Common names of trees, if available, are used in the text.
5 Italic numbers in parentheses refer to literature cited, p. 95.
4 TECHNI CAL BULLETIN 1 i 3 3, tJ . S. DEPT . OF Acm r CULTttRE
pheric pressure prevails. The weather b ecomes warm, and even .hot,
with occasional precipitation.
South of th e Alaska R a n ge t h e annual precipitation averages abou t
20 inch es, with approximately 14 inch es at Anchorage and 24 t o 30
inch es in t h e Susitna Valley. About on e-third of t h e prec ipitation
falls dur ing t h e period Niay to August, most of it in July and Augu s t.
The Janua r y m ean temperature is a r ouncl10° F . and t he July m0an is
about 57°. In t h e winter the t emp erature may drop to abo u t -36° F.
and in summ er attain a hi gh of 90°. The growing s eason i s u sually
l ess t h a n 90 d ays.
J orth of the Alaska Range, in the Yukon and Tan a n a River Valle~·s,
t h e annual precipitation is l ess t h a.n 20 in ch es, commonly b etw0 en 10
and 15 inches. About h alf of it falls during May t o Au g u st, a nd
within t his p eriod two -t hiTd s d uring July and August. January
mean temperature varies considerably from place t o place; in some
lo calities it is lower than -20 ° F. Mean temperature in July is
about 60° F . In summer, temperatures as high as 100 ° F. are known
and -in ,winter t h ey fall a s lo w a.s -78°. The growing season varies
from a bout 60 t o 90 days.
T A BLE 1.-T empera luTe and pTec1:pi talion i n th e Alas ka inleri01· (70)
rrempc rn turc Precipitation
Grow-
Station Ja.n u-ing An-Se p-Length ary J ul y l\laxi -:Mini-sea-L2n gth nual 1\fay-tern-of rec-aver-aver-mum mum so n of rec-aver-Aug-ber-ord age age ord age ust 1 A pril '
------------------
Y ears oF. oF. oF. oF. Days Y ears I nc hes Inches I nc hes
So u t h of Alask a Range: Anchorage . ______________ 22 11. 2 57.0 92 -36 110 22 14.32 5. 35 8. 97 K ennecott_ _____________ -24 4. 5 52 .4 80 -39 91 20 21.60 8.04 13.56 Matanusk a._ _____ : _________ 19 12.6 57.7 D1 -36 19 15.61 r,, 43 9.18
Susitn a. __ -------------__ 6 9. 1 57 .7 86 -37 6 26.88 10.39 16.49
'l'alkeetna ____ -------_____ 19 7. 6 58.0 90 -48 72 18 30.03 11.38 18.65
N ortb of Alaska Range: Allakaket ________________ 24 -20.3 57 . 7 90 -70 54 25 13.10 6. 10 7. 00 D awso n __________________ 37 -21.0 59.3 92 -66 37 12. 69 5. 34 7. 35 F a irb anks _______________ -34 -11.6 60.0 99 -66 89 34 11.87 .). 89 5. 98 Fort Yukon ______________ 23 -21.6 61.2 100 -78 81 23 6. 88 3. 63 3. 25 Holy Cross _______________ 35 -0.4 56.5 93 -58 90 20 20 .06 8. 46 11.60 McKinley Park __________ 16 1.9 54.3 89 -54 63 15 15.28 8. 56 6. 72 N nlato ___________________ 13 -7.5 57.5 90 -62 13 16. 50 6. 46 10 .04 Ruby ____________________ 6 -7.5 57.5 98 -52 6 17.77 8. 38 9.39
rran ana __________________ 37 -12.5 58.3 91 -76 64 38 13.63 6. 94 6.69
University Expt. Sta _____ 34 -10.2 59.9 99 -65 34 11 .76 5.88 5.88
' 'l'otal of average monthly precipitation.
T emp erature and prec ipitation in interior Alaska are nicel y bal-
anced. A substantial incr ease in either, without a comp ensating
increase in the other , probably would l ead to l ess favorabl e growing
condition s than ex ist today. Tab er (150) describ ed this as follow s:
Th e abundance of vegetaLion on p er ennially froz en ground in
Alaska is partly due to low pree ipitation; for with t h e low tem-
peratures, if t h e prec ipitation were high enough, mo st of the
smface would b e bmied under sno"-and i ce . Also , a ri se in
temperature, r es ultin g in the thawin g of t h e grow1d , and t h er e-
fo re b etter drainage, could conver t much of it into a semi-d eser t
unless t h e prec ipit ation w ere also in cr eased.
ECOLOGICAL EFFECTS OF FORES'l' FIRES I N ALA SKA 5
Forests
The forests of the interior of Alaska r epresent one of the greatest
r en ewable rcsomces of the r eg ion. Po tential production of wood
ce llulo se is ve r y gr eat .
From th e air the pat te rn of for est and other vegetation is a eomplex
mo saic of t~']JeS (fig. 2 ). In general, th e forest occ upie s t h e valleys,
often appearing a s b elL s or ribbons along the str eam s, lower slopes,
and low be nchlands. Throughout mo st of t h e area t h e timbe rline
is comparatively low, b etwee n 2,000 aud 3,000 f ee t.
Fire is on e of a number of fa ctors r es ponsible for t h e gr eat com-
plexity of the vegetation pattern. Only when the influenc e of pas t
fires is recogniz ed can one begin to account for t h e seemingly hap-
h azard mosaic of vegetat.ion. Th e sharp boundaries between stands
of asp en or birch and white spruce are the edges of bmns . The iso-
lated stands of a few acres of whi te spruce, the upland s tringers, and
even the scattered trees are r elic t s of extensive stands that have
been d es troyed b y fir e. In many lo calities, areas that are n ow tree -
l ess formerly supported full for est stands that were d estro yed b y fu ·e.
Another influence that contributed to the diver sity of vegetation
is the o cc urrenc e, in somewhat complicated pattern, of p ermafrost
(permanently frozen ground). This phenomenon frequ ently r es ults
in poor soil drainage and poor soil aeration, r es tricted root space,
and co ld soil. Within the forest ed portions of the interior, either
slow, impeded drainage (wh eth er associated with p ermafrost or not)
or excessive drainage result in outstandingly poor si tes for tree
F -477357
FIGURE 2.-View of t h e Copper River Valley, showing a mosaic of fore st types,
white spruce, quaking aspen, and willo w. This pattern reflects the complex
fire history of the area.
6 TECHNICAL B ULLETIN 113 3, U . S . DEPT. OF AGRICULTURE
growth. Sharp boundaries b etween vegetation typ es ar e mo st fr e-
quently c aused b y fir e whereas t hos e caused b y to pography and
associated influ en ces are apt t o b e diffu se.
The principal for ested areas south of t h e Alaska Range include
t h e following drainages, from east to west: the Copper River and its
man.\r l arge tributaries, t h e ::VIatanuska River , the S u sitna Kiv-er
and i ts tribu taries, upp er Cook Inlet, including t h e west sid e of t h e
K enai P eninsula, and t h e Iliamna L ake-Lake Clark a nd N ush agak
River sec tions. The t wo l ast-men t ion ed section s drain in t o Bristol
B ay and not in to t h e Pacifi c Oce an. North of the Alaska R angC',
timb er occurs exten si ve!~-in t h e Tanana, Yukon , and Ku skokwim
River region s . I t is no tewo r th y that consid er abl e areas of forest
oc c_ur north of t h e Arctic C ir cl e, as along t h e Porcupine and i ts tribu-
tanes, the Chandalar , the upper Ko) ukuk, and t h e Kobuk River s.
Trees grow north of l atitude 68° N. on t.h e so u t h slop es of t h e Brooks
R ange and a s far west as t h e N iukluk River, n ear Co uncil , on th e
Seward P enin s ula; t his is t h e w esternmost occ urren ce of fore st growt h
on the N ort h American continent. In 19 01 Collier (34) r epor ted
that spruce trees in t his lo cation attained diam et ers of 12 inch es
and h eights of 50 f eet . A treel ess b elt alon g t h e B ering Sea coast
extends inland for as much as J 50 miles . Lo cally, however , trees
exte nd to t h e coast; 'Voolfe (165) r eported findin g d ense gro.ves of
s pruce within a qua r ter of a mil e of t h e sea at N orton Sound. They
wer e 6 (.o 10 inch es in diam eter a nd not over 40 f eet in h eight.
A ccurate data on t h e exten t of t h e forested area of t h e in terior will
not b e available unt il s urveys ar e made . C urren t estimates ar e
based on the opinions of ex p erienced observer s, rough maps prepared
b y for es t er s and other s who h ave fl own over t h e country, a nd r eports
of t h e G eologi cal Survf'y and o h er governmen tal agencies . According
t o t h ese estim ates, about 120 million acres b ea r s uffi cien t t r ee grow t h
t o warr ant d esignation as forest l and. Of t hi s acreage, some 40 million
a m·e s are b eli eved to b e omm rcial or po tentially commer cial fores t
l and. These l ands now s uppor t (or did support b efore d estruction by
fir e) fairly d ense stands of white spruce, or s u ccess ion a l stages l eading
t o t h at typ e. Some 80 million acres of t h e in terior b ear sp~rs e forests
of op en woodl a nd . A ccessi bili ty a nd m er ch a n tabili ty are concepts
t h at for esters h ave l earned to u se with caution . In a modern techno-
log ical world both can change qui ckly and drastically . Judged b .v
present conditions, however , i t may b e estima te d t h at a bou t 14
.million acres of t h e commer cial or po ten t ially commercial in terior
for ests are presently accessible a nd more or l ess in u se .
From t ime to tim e other es timates have b een m a d e on timb er
resources in t h e interior. I n 1910 K ellogg (69) estimated that t h e
interior for est north of t h e Alaska Range amounted t o some 80 million
acr es . Thomas P. Riggs, Jr., early Go vern or of Alaska, who s p ent
many yea.rs in the T erritory as a m ember of both the Alaskan Engi-
neering Commission and the I nternational Boundary Commission ,
estimated t h at th er e w ere about 8 ,600 square miles, or 5,504,000 acres,
of m er chan table sawtimber in t h e in terior and that t his would average
not less t han 5,000 board-feet p er acre (56). Riggs' estimate, by
drainages, was as follow s:
ECOLOGICAL EFFECTS OF FOREST F IRES I N ALASKA 7
JVIerchctntable sawtimber area
River bas in : (square miles )
Y u kon Vall ey and s mall trib uta.ri es __________________________ 3, 000
Tanana Va ll ey and s mall t ributaries __________________________ 1, 000
Porcupine________________________________________________ 250
J{oyukuk _________________________________________________ 500
Nenana __________________________________________________ 100
Kant~hn a ________________________________________________ 200
Chan dalar _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 250
Sus~na ___________________________________________________ 300
Ku skok\\·im _______________________________________________ 1, 000
Kandik, Se ventymile, Charley, Birch, Beaver, Tolovana, C hena,
D elta, Innoko, Idita rod , etc _______________________________ 2, 000
Rig·gs included onl:v one drainage (S u sitna) sout h of t h e Al aska Range.
Guthrie (56) sta te d that "the forests of interior Alaska are estimated
to comprise not l ess than 150 ,000 ,000 acres."
The forests of the Alaska interior are analo gous to, if not synony-
mou s with, the taiga of Sib eria . Hustich (64) stated that taiga was
originally a Siberian word u se d for the boreal forest. H e wrote,
"The north ern main for es t types in th e taiga seem to occur in the
whol e boreal forest r eg ion, in Canada, Alaska, and Eurasia. We
know t h at the arctic and s ubarctic plants are mostl~-the sam e in the
whol e Arcti c a nd Subarctic . Also their sociological affinity to each
other is the same." A cc ording to Nuttonson (103) the term taiga
"implies a coniferous northern for es t with no admixture of non-
coniferous sp ec ies save the birch a nd aspen."
The principal for est typ es en counter ed are briefl y di scu sse d below
and in d etail in the section on Effect of Fire on Forests .
White spruce is the climax type on w ell-drained s oil s. When
destroyed by fir e the same species may b e r eproduced at once but
more commonly Alaska paper birch or quaking aspen comes in .
These t wo species often occur in essentially pure stands bu t mix t ures
are al so well known. A s su ccession progresses, white spruce enters
the birch and aspen stands and finall y assumes a dominant position
as the shorter li ved birch and aspen drop out. Balsam poplar, t h e
common cottonwood of the interior, i s usually found on r ecent
alluvium along streams and on flood plains. On poorly drained
forest ed sites, black spruce is invariably dominant. Locally this
species may appear on uplands, forming pure stands as a "fi re typ e."
Some form erly forested upland ar ea s have been burned so sever ely
and so frequ en t ly that they are now treel ess or nearly so. Close
examination often disclo ses relicts of s pruce (c harred stumps, portions
of boles, etc.) in areas now supporting only grass and fir eweed or
shrubby willows .
The view is sometimes expressed t h at t h e trees of the in terior are
all small a nd scrubby, and that their growth is excessively slo w.
This generaliz ation is wholly unwarran te d (fig. 3) and probably is
based on obser vations along roadsides where burning has usually
been most fr equ ent. Ther e are many r ef er en ces t o timber conditions
in the r eports of early ex plorers in the T erritory, chiefly in those of
the G eological Survey . A series of r eports o'n maximum sizes of
spruce trees and on the position of the t imb erline h ave b een co mpil ed
in table 2.
The timber seen b y t h e early exp lorers was more indicative of
potentialities than are th e modern for es ts, whi ch h ave suffere d sever ely
8 'l'ECHN ICAL BULLETIN 1133 , U. S . DEPT. OF AGRICULTURE
F-47 7358
l<'rGURE 3.-A cross section of 6-inch d. b. h. whit.e s pruce, s howing 24 a nnual
rings. The ring width shows r e markably good growth. Vicinity of Kas ilof,
Kenai Peninsula, 1949.
from fires during the past half centmy. Diameters of 18 to 24 or
more inches were commonly reported by early explorers. Even north
of the Arctic Circl e, on the headwaters of the Porcupine River,
Robert Kennicott (33) found spruce 36 inches in diameter , and in 1901
Schrader (137) reported spruce exceeding 24 inches in diameter in the
Chandalar-Koyukuk r egion. South of the Alaska Range, in a grove
of spruce on the Kakhtul River (a tributary to the 1/fulchatna River)
Schanz (135) in 1893 m easured nine trees , each of which was over 3
feet in diameter.
Learnard (76) in 1898 , on his trip up the Susitna River, cut a tree
that furnished s uffi cient lumb er for a boat 35 feet long and 5 fe e t
wide at the bottom. He wTote, "At Croto Creek [now called Deshka
River], where the boat was built, no difficulty was experienced in
finding a spruce tree from which ten planks were sawed which ·were
35 feet long and average 11 inches in width. Many other trees were
seen full y as l arge as the one cut for the boat."
On 58 sampl e plots with spruce of merchantable size, the average
volume per acre was 2,400 cubic feet (trees 5 inches in diameter and
larger to a 4-inch top) or about 8,000 board-feet (trees 7 inches in
diameter and l arger to a 6-inch top, Scribner rule). The average age
ECOLOGICAL EFFECTS OF FOREST FIRES h~ ALASKA 9
TABLE 2.-JI.!Iaximum spruce size and elev ation of timber line reported by various
explo1 ·ers
R eg ion
South of Ahsk a R ange: Kakh tnl River_. ________________________ _
Mo unt Spurr_ ___________________________ _
Lo"·er Skwentna Ri ver_ ________________ _
Will ow Creek-Kash witna Rh•er_ ________ _
Chulitna Ri ve r __ ---------------------__ _
'f alkeetna River ________ ----------------_
Tonsina Ri ver __________________________ _
Copper Ri ve r -----------------__________ _
)forth of Alask a R ange : Alask a R ange. __________________________ _
'f'anana-\Yhi te Rivers ___________________ _ Upper T a na n a River_ __________________ _
Big Tok Ri ve r __________________________ _
Y ukon-Tan an a Rive rs __________________ _
Coal Creek . _____________________________ _
Fortymile River ________________________ _
Tatoudnk-Nation R eg io n _______________ _
Cbandalar·KoyuJruk R eg ion ____________ _
Shcenjek Ri ver ____ ··--------------------Porcupine-Y ukon Rive r__---------_____ _
H eadwaters of Porcupine Rive r_ ________ _ Kobuk River ___________________________ _
Y! mile from Norton So und ______________ _
N iukluk River, ncar Council , Seward
Peninsul a.
ll faximum siz e of
s pruce Elevation
Obse rver 1------,.---1 of w~~er·
Diameter H eight
I nches Feet Feet
Sch anz (185)__________ 36+ ----------------------Cap ps (!!7)____________ 30
Ca pps (£9)____________ 24
Capps and Tuck (80).. 36 ----------
Capps (£6) ____________ ----------------------
Capps (£6)____________ 24 ----------
i\'foffit (98)--··-·-------____________ ----------
Schrader a ud Spen ce r 36+ ----------
(188).
2, 300
2, 000
I , 800-2,000
2, 000-2, 500
2, 000
3, 000
3, 000
Eldridge (4£) __________ ----------------------3, 000
Brooks (19)___________ 24 3,400
Pearson (111)_________ 18 ----------------------
Rice (1£9).____________ 24+ 100 ------------
i\ier tie (95) ____________ ----------------------2, 000-3, ()()()
Osgoo d (107)__________ 19.7 80 ------------
Barnard (9)___________ 22 100 3, 000-3,200
Mertie (9 4L-----------______________________ 2, 500-3,000
Schrad er (187)_________ 24+ 100 ------------
iVIertie (98) ------------24 ----------2, 000-3, 000 Cairnes (1!8) .. _________ 18 2, 900
Kennicott (88)________ 36 ----------------------
McLenegan (88)_______ 24 ----------------------
\Voolfe (165)___________ 10 40 ------------
Collier (84l------------12 50 ------------
was about 120 years. · Rotation age might be about 160 years and at
that time the average diameter of the trees would be 8 to 12 inches.
At 160 ye ars t h e better sprp.ce stands would average perhaps 3,900
cubic f eet or 15 ,500 board-feet per acre. Indications are that at the
rotation age suggested 80 p ercent of the trees in the stand would be
5 inches in diame ter and larger and 20 percent would exceed12 inches
in diameter. Some of the trees would havG attained diameters of 18
to 20 inches.
On the 40 million acres of commercial or poten,tially commercial
interior forest land there is estimated to be a bout 32 billion cubic fe et
or 180 billion board-fee t of white spruce, Alaska pap er birch, aspen, and
cottonwood . Volumes on the 80 million a cres class ed as woodland are
purely conjectural.
Even if current estimates of timber acreage and growth and yield
in the interior prove to be too high, the for est r eso urce will still be so
tremendous and so important to the future ec onomy of Alaska that
it must r ece ive full consideration in the national program of forest
conser vation .
HISTORY OF FOREST FIRES IN INTERIOR ALASKA
Forest fires ar e welllmown throughout the ti¢bered regions of the
far north. Their extensive and r epeated occ urrence in prehistoric,
historic, and modern time (fig . 4) is well substantiated. The record of
fire occurrence in prehistoric time can be read in t h e forests themselves;
the journals and reports of explorers a!!-d travelers continue the r ec ord
to modern time .
10 TECHNICAL B U LLETIN 11 33, U. S . DEPT. OF AGRICUL'l'URE
FI GUR E 4.-Yankee-Ophir C ree k fir e, vY N w of McGrath in t h e Kuskokwim Rive r
region. This fir e covered an a r ea of abo u t 175,000 acres , 1941. (Pho to b y
Bureau of L and Management, U. S . D epartme n t of the Interior.)
Forests of the north are es p ec ially li abl e t o d estru ction b y fir e.
R elatively low precipi tation, long hours of s unshine during the sum-
m er p eriod, and r emarkably high air· temperatures increase t h e fire
hazard in for ests which, by their· very nature, are r eadily flammabl e.
The northern for ests are characteristically coniferous with compara-
t ively sm all trees, often s uppor t ir1g a h eavy growth of b eard li chens.
FirP carries r eadily in d ense stands as it also do es in op en stands; in
the latter th e trees r e tain t h eir· branch es to the ground and the inter-
vening s paces are blanketed with a cover of mosses, li ch en s, and small
shrubs, commonly m·icaceo u s. In the summer the mosses and li ch en s
b ec ome extr em ely dry and tinderlike.
In 18 8 9 B ell (11) d escrib ed fore st fire s in northern Canada as follows:
The trees are crowded so clo sely together t hat t h eir· branches
t ouch or intermingle . The ground is d eeply covered with dry
moss. After prolonged hot weather and drough t the moisture
b ecomes thoroughly dried out of the gummy leaves and branches ,
l eaving t he r es in and turpentine r eady for ignition . All the con-
dition s are now present, and only awai t a spark of fir e to give
rise to one of the wildest scen es of d estructio n of which the world
is capabl e. When t h e fire has once started, the pitchy trees burn
rapidly; the flames rush through their tops and 'high above them
with a roaring nois e . Should the atmosphere b e calm, the as-
cending h eat soon causes the air· to flow in , and after a time the
wind acquir·es great velocity. An irT es istible front of flam e is soon
d evelop ed, and it s weep s forward , d evouring the forest b efor e it
like the dry grass in a running pra ir·i e fir e, which this r esembles,
ECOLOG I CA L EFFECt'S OF F ORESt' FIRES IN ALAS K A 11
buL on a g igan t ic scale. The irregular line of fir e h as a h eigh t of
a hundred f eet or m or e a bove t h e trees, or t wo hundred from the
ground. Great sh ee t s of flam e app ear t o di sc onnect t h em selves
fr om t h e fi er y t or r en t a nd l eap upward and explode, or d ar t for·
ward , bridging over op en sp aces, su ch as l ak es a nd river s, a nd
starting th e fir e afr es h in a d van ce of the m a in co lumn, as if im·
p atien t of t h e slo wer p r og r ess which i t is m aking . Th ese imme nse
sh oo t ing fl a m es a r e prob a bly clu e to t h e large qua n t i t ies of in fl am·
m a ble gas evol ved from t h e h ea te d t r ee t op s just in a d van ce of
a ctual combus tion , and th ey h elp t o acco un t f or the almost
incredible s p eed of s ome of t h e l a r ger for est fir es, one of whi ch
w as known t o run ab o u t 13 0 miles in twelve hours, or upward s of
t en mil es an hour.
B ell 's d escrip t ion was based on ex p erien ce gained during m or e t h a n
3 0 summer s s p en t in northern for ests.
Ex te n s ive fir es in north ern fo rests are not p ec uli ar to Al aska .
N or thern Russ ia and Sib eria h ave ex p er ien ce d t h e sc ourge of for est
fir es clo wn through t h e years. M iclcl enclorff (96) in hi s 186 7 r ep or t
of his famous journey t o n or thern and eas t ern Sib eria rep eatedly
commen ted on t h e exte n sive fi res en counter ed and t h e even more
ex ten sive eviden ce of p ast fir es. H e p asse d t hrough "hundred s and
t hous ands of s qua r e versts which fir e h a d d estroyed " (ver st= 1.067
km . or 0 .662 9 mile). In 1917 Pohle (11 P) stated t hat in nort h ern
Russ ia, as in Siberia, for est fi res occur year a fter year as a r es ul t of
the car el ess n ess a nd imprude n t conduct of t h e p eopl e. Pras olo v (1 21 ),
in discu ss ing t h e soils of the U r als and east Sib erian upla nd in 19 32,
wrote as follow s: "The bo'gs and w ood ed s wamps ar e t h e princip al
ob stacl es t o t r avel in t h ese nort h ern fo rests, t ogeth er wi t h t h e gr eat
qua n t i ty of burnt f allen t imb er t h at cover s t h e groun d , t h e so-call ed
gari. This f allen t imb er m a k es up t h e norm al l a ndscap e of t h e r eg ion ;
it is diffi cul t to find a ny w ood untou ch ed by fir e." P erhap s t h e most
r eadily access ible acco unt of for est fir es in S ib eria is that of Shostako-
v i tch (1 1,.5) in 192 5. H e d escrib ed th e particul a rly b a d fires of 19 15 ,
which wer e estimated t o h ave d estro yed t he f or est over a n ar ea of
55,000 s qu are miles, a n a r ea equal t o a bout one-t hi rd of wester n
Ew·op e (excludi ng Russ ia). Smo ke from t h ese fir es spread over a n
area of s ome 2 ,632,000 s quare m iles, a bou t equal t o t h e w hole of
Europ e and over f our t imes t h e ar ea of Al ask a. So m e of t h ese fi res
in Russia a nd Sib eria r es ulted from lig h t ning but most wer e cau se d
by man (1 1,.5).
The fo rests in t h e nort h ern p arts of t h e Scand inavian co un tries
have also ex p erien ce d r ep ea te d fi res . For example, Rubner (1 32)
sta ted in 1927 t h at in nor t h ern Fin l and, almost all of t h e for es ts bore
t r aces of fir e.
C ondi t ions in no rth ern C a nada ar e similar t o t ho se in a l ar ge p ar t
of Alas ka. In 1889 B ell (11 ) stat ed t h at "No twithstanding i ts
immen se exte n t, i t m ay b e said that fir e has rlin t hrough ever y p art of
it at one p eriod or a no t h er." The journals of1 S amuel H earne a nd
Philip Tmn or, writ t en b etween 1774 and 179 2, included r epor ts of
ex te n sive fir es in C a nada (1 58). On July 14, 1774 , H earne m a d e t h e
follo wing entry in his journa l: "l\!I ost of the wo od s which we cam e b y
for t h ese 2 D ays P ast have form aly b en set on fir e, as >var e a lso in
many o t h er Par ts as w e came along ." On July 3 0, 178 1, Turn or
12 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
wrote of "the Land rather bold with Woods now on fire." In 1843
Davies (36) expressed the view that "fires . . . have ravaged the
whole country. Indeed, there can be but little doubt, that one time
nearly, if not the whole, of the interior of Labrador was covered with
wood, which has since been destroyed by fire."
Various Canadian writers have regarded Indians as a major cause
of forest. fires in earliest time. Davies (36) in 1843 and Low (83) in
1896 reported that Indians started fires for smoke signals and believed
that the signal fires were responsible for burning much country.
General carelessness of Indians with campfires, especially when not on
or near their own h;unting grounds, was also regarded by Bell (11) in
1889 and Low (83) in 1896 as a major source of forest fires. But the
full burden of responsibility for forest fires cannot be placed on
Indians. Bell's list o£ those who share the responsibility is rather
complete: "These include fur traders, missionaries, surveyors, ex-
plorers, prospectors, etc. and, nearer to civilization, railway builders,
common-road makers, lumbermen, bush-rangers, and settlers." Raup
and Denny (126) reported that along the southern part of the Alaska.
Highway stands that do not show some effects of fire are rare.
Perhaps the earliest written record of a forest fire in Alaska is that
of the Russian mining engineer Doroschin (37) who, in 1850, ascended
the Kenai River in search of gold. He reported that he could not
complete his investigations because of a forest fire that he encountered.
In the years that followed acquisition of Alaska by the United States,
exploration was extended and references to forest fires became in-
creasingly frequent. ·
Allen (5) encountered extensive fires on the upper Tanana River.
In 1885 he reported,
Heavy smoke, caused by extensive timber fires, obscured the sun
the entire day, so that an observation was impossible. This
smoke had originated from signal fires which were intended to
give warning of our presence in the country. When we first
arrived at N andell's there was only an occasional smoke around,
but as his guests departed for their different habitations each
marked his trail by a signal fire. The prevailing wind was from
the east and carried the smoke along with us. In answer to the
fires on the south bank new ones started on the north, so that for
nearly two days we barely caught a glimpse of the sun except
through the heavy spruce smoke.
Glave (49), on an extensive hunting trip, wrote in 1892 that "Miles
and miles of blackened stumps marked the ravages of forest fires."
In 1894 Schwatka (140) reported that "Evidences of conflagration in
the dense coniferous forests were everywhere frequent ... " on the
upper Yukon. He also stated that "Ahead of us there still hung
dense clouds of smoke which seemed as if the whole world was on fire
in tha.t. direction." •
In 1898 Abercrombie (3) encountered large fires in the vicinity of
the head of Klutina Lake. He stated, '
I noticed that there was quite a mound of petals under each spruce
tree, the branches coming close to the ground. When a fire had
eaten its way to one of these trees through the moss, the petals
would ignite and the fire, rushing up the tree with a roar, would
create a flame 150 feet high. This would send forth a shower of
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 13
sparks that would start thousands of additional fires, each to
repeat the operations of the first. The entire valley seemed to be
on fire, which made travelling through the timber very dangerous,
as the falling trees were liable to injure man or beast, if they did
not stampede the entire pack train.
On his journey to the Tanana River in 1898, Glenn (50) traveled
through the country north of Bubb Creek, a tributary of the Tazlina
River. He recorded, "We entered what we called the 'burned district,'
which seemed to extend as far as the country is visible toward the
Copper River, and to the northward almost to the Alaska Range."
The statements quoted above were made by trained observers
engaged in serious exploration. They supply indisputable proof that,
even prior to the entry of white men in numbers, the forests of the
Alaska interior were ravaged by fires.
In earliest times fires were caused, as they are today, by lightning,
but there can be little doubt that Indians were the major cause. The
habit of using signal fires as a primitive means of communication was
evidently widespread throughout the northern forests of America.
References to this practice in eastern Canada by Davies (36) in 1843
and Low (83) in 1896 have already been cited. The practice was
reported in Alaska by the following early writers: Schwatka (139, 14-0),
Allen (.5), Glave (49), Haskell (57), and Learnard (76). Glave (49)
in 1892 observed the practice in operation and wrote of his Indian
guide, N anchay, "He began an incessant signalling by burning trees,
and by and by the keen eyes of Tsook [the son of the guide] spied a
faint curl of smoke creeping up from the wooded brow of a hill about
ten miles away, which told of the wh.ereabouts of the missing family."
In addition to the use of fire for signalling, the Indians also employed
smoky fires to protect themselves from mosquitoes (49, 57). They
set general :fires to drive mosquitoes and gnats out of the country
(5, 140) and to burn out dense undergrowth so they could see large
game as it passed over the burns (3).
Carelessness with campfires must also be reckoned as an important
source of fires in the early days. Bell (11) in 1889 remarked, "It
gives them some trouble to put out a fire completely when they leave
a camp, or where they may have stopped to cook a meal or gum their
canoe by the way, and an Indian will seldom do anything except by
necessity." ·
The tempo of forest destruction in Alaska was substantially in-
creased after gold was discovered in the Klondike in 1896. The
fabulous stampede that followed brought thousands of people to the
Yukon and to Alaska. From 1898 on to 1939, when the Alaska Fire
Control Service was organized within the General Land Office of the
U. S. Department of the Interior, tremendous acreages of forest land
were blirned nearly every year. The tragic record of resource waste
during this period may be found in contemporary reports and on the
face of nearly every landscape. It is not feasible to present here a
detailed record of the destruction suffered by the interior forests since
the gold rush, but attention will be directed 'to sample testimony.
Those interested will find abundant material on forest fires, their
causes, extent, and destruction in the writings of Rohn (130, p. 414),
Brooks (19, p. 489; 20, p. 42; 21, p. 206), Moffit and Stone (99, p. 50),
Kellogg (69), Graves (53), Guthrie (56), Drake (38), and Moffit (98).
14 TECHNICAL BULLE'l'IN 113 3, U. S. DEP'r. OF AGRICULTURE
Few men have had the intimate personal knowledge of Alaska that
was possessed by the late Alfred Hulse Brooks of the Geological
Survey. This keen observer (21) stated in 1911:
In the inland of the province the supply of timber at best is rather
scanty but would probably be sufficient for local use were it not
subjected to ravages by forest fires nearly every year. Such fires
occur on both sides of the Alaska Range, but especially in the
Yukon basin, where the semiarid eonditions often aJlow the forest
fire to sweep over miles of territory until it is stopped by a water-
eourse too wide to he crossed. It is no exaggeration to state that
hundreds of square miles of timber have been burned off the
Yukon basin during the last decade. This burning of timber is in
part clone purposely by both whites and natives in order to get
riel of insect pests or to improve the growth of grass near their
habitations, and is in part due to carelessness. The writer has
traced at least one forest fire to a native camp. But the amount
of timber annually destroyed by the natives is small compared
with that for which t.he whites are responsible. Many a white
man has deliberately started a forest fire which swept over miles
of country, solely that he might obtain a few acres of dry wood
for winter use. If this willful waste does not stop, the time is
not far distant when there will be a scarcity of timber even for
local use. Timber grows very slowly in this northern field, and
once destroyed it probably cannot be replaced for several genera-
tions. It appears to the writer that at the present rate of con-
sumption and destruction by forest fires the timber of the Yukon-
Tanana region will not be sufficient for the plaeer-mining industry,
let alone any possible development when this st.age has been
passed. .
Graves (53), after a visit to the interior in 1915, reported, "The
interior forests of Alaska are being destroyed at an appalling rate by
forest fires. Conditions existing in the western United States 25 years
ago are repeating themselves in Alaska." Moffit (98), writing of the
Tonsina district, mentioned several of the common reasons given for
burning the forest. He concluded, "Yet in spite of any benefits that
may have been involved in the practice, it is true that much of a
valuable resource was destroyed beyond the hope of early replace-
ment, for trees in the north country grow slowly."
The acreage of forest land in Alaska burned annually from 1898
to 1939 is not known but it probably averaged more than 1 million
acres. During single bad fire years, as for example 1915, several
million acres were burned.
Annual fire losses recorded from 1940 through 1945 by the Alaska
Fire Control Service and from 1946 to 1954 by the Bureau of Land
Management, U. S. Department of the Interior, are as follows:
F . Forest land burned Ire Season: (acres)
1940 _________________ 4, 500,000
1941_ ________________ 3, 654, 774
1942_________________ 45~ 510
1943_________________ 66~ 773
1944_________________ 11~ 604
1945_________________ 117, 313
1946 _________________ 1, 438,963
.1947 _________________ 1, 431, 665
Fire season: Forest land burned
(acres)
1948 ________________ _
1949 ________________ _
1950 ________________ _
1951-----------~-----1952 ________________ _
1953 ________________ _
1954 ________________ _
35, 190
18, 147
2, 063, 983
.221, 669
74, 690
472, 549
1, 430, 645
I
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 15
Over this 15-year period the average acreage burned during each
· fire season was approximately 1.11 million acres. During the first
two years covered by the record, the Alaska Fire Control Service wns
in the process of organization, assembling equipment and personnel.
These were also years with dry fire seasons and mining was in progress
throughout Alaska.· Fire prevention education was in its infancy.
The marked decline in fires during the war years, 1942-45, is probably
the result of a combination of circumstances. Mining activities
ceased, nearly all civilian travel to the Territory was restricted and a
large portion of the widely scattered population was drawn to con-
struction centers.
In 1946 and 1947 there was a return to civilian activities, a dispersal
of the population, and an influx ofsettlers and others. The remark-
ably small acreages burned in 1948 and 1949 reflect the wet conditions
during the fire seasons of those years. The large area burned in 1950
was due primarily to the great fire of some 1,800,000 acres in the vicinity
of Fort Yukon. Although drought conditions prevailed in the Ter-
ritory in 1951, the acreage burned was relatively modest. This com-,
mendable record evidently reflects the increasing efficiency of the fire
control organization of the Bureau of Land Management.
The following notes on some of the larger fires were made available
through_ the courtesy of R. R. Robinson, Area Forester, Bureau of
Land Management, U. S. Department of the Interior.
1893 A fire near the town of Knik burned about 135,000 acres.
1896 Fires started by miners in the local gold rush burned along
the entire length of Canyon Creek (in the Sunrise area);
34,000 acres were burned.
1915 The Sourdough Hill fire, presumably set by sparks from the
Copper River and Northwestern Railroad, burned from
Chitina to the Kennicott River and from the Chitina River
to the mountains on the north; 384,000 acres were burned.
The Kennecott fire, presumably set on a windy day by one
man using oil-soaked rags,' burned all the timbered country
between the Kennicott and Nizina Rivers. This fire was
reportedly set to kill the timber so as to provide fuelwood for
sale at the Kennecott mine; about 64,000 acres were burned.
1920 Middle·Fork of the Chandalar River fire. This started on
the East Fork and burned across to the Middle Fork, cover-
ing a tract about 15 miles wide and 12 miles long; 115,200
acres were burned.
1922 Mosquito Fork Flat fire. This fire burned all of the Mos-
quito Fork watershed; it started 6 miles west of Long Cabin
on the old Valdez-Eagle trail on the divide between Permis-
sion and Mosquito Creeks. The area covered was about 48
miles long by 30 miles wide; 921,600 acres were burned.
Salinon Village fire. This fire burneg about 448,000 acres
on the Black River and Porcupine River.
1924 Foraker Creek fire, Lake Michumina area.; 200,000 a.cies
burned June 12.
Birch Creek fire, Lake Michumina area; 150,000 ~teres
burned June 13.
349169-56-2
l
./
16 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
1926 Mile 17 Richardson Highway fire. Started by children who
set a tree afire to drive out a squirrel; 38,400 acres were
burned.
Chatanika River area fire; started by construction crews;
area· assumed to be in excess of 100,000 acres.
1927 Willow Creek fire, Copper River countr.)r. Started by con-
struction crews. Burned between the Copper River and
Tonsina River with the Richardson Highway as the western
boundary. Area. burned, 128,000 acres.
Columbia Creek fire, Fairbanks district. Presumably
started by a rancher who set a fire to scare bears that were
muddying the water hole used by his horses. Area bmned,
5,000 acres.
1930 Beaver fire. Started at Beaver and burned 15 miles east
and 14 miles north; area covered, 134,400 acres.
1934 Henry Martin fire. .Area bmned, 144,000 acres in District 3.
1935 Kvichak River fire. This fire, started about May 20, ex-
tended over about 640,000 acres. .
Iliamna Lake fire. Over 1,900,000 acres. bmned.
1936 A fire started 10 miles east of the mouth of the Black River
and burned to the head of Rat River; 288,000 acres bmned.
1937 Sheenjek River bmn. Started at Bootleg Bend on the
Porcupine River, burned to the Sheenjek River, then north-
easterly to Fortymile on the Coleen River. Believed to have
been started from a smudge fire set by a rat trapper. Area
bmned, 312,320 acres.
1940 Box Car bmn. This fire started at Eight Mile on the Porcu-
pine River, burned to the mouth of the Sheenjek River and
across to Christian River; 192,000 acres burned.
Stevens Village :fire. . This fire bmnecl from Stevens Vil-
lage 20 miles north and 10 miles south, averaging 10 miles
in width; 192,000 acres were bmnecl.
Ruby-Poorman fire. The area burned extended from
Ruby to Poorman. It bmnecl all summer, from June to
Au;;ust; .1,250,000 acres were burned.
Other large fires in 1940 included the following: Stoney
River, 750,000 acres; Candle, 450,000 acres; Tanana River,
192,000 acres; and Birch Creek, 640,000 acres.
1941 Eel Berg fire. Started 25 miles up Beaver Creek and burned
across to Birch Creek and then between the two streams to
Fifty Mile; 216,320 acres burned.
Beaver fire. Extended from the East Fork of the Chanda-
lar River to the Hodzana River, jumping the Hadweenzic
River; 268,800 acres were bm·ned.
Fishhook fire. Burned from Fishhook town to the Little
Black River, thence down the Little Black for 10 miles and
back to the Black River; 128,000 acres were bmned.
Other large fires in 1941 included the following: Wood
River, 252,800 acres; Porcupine River, 256,000 acres; Ruby
(2 fires), 202,000 acres; Galena, 112,000 acres; Unalakleet,
1,000,000 acres; Selawik, 500,000 acres; Kobe, 136,640
acres; and Beaver Creek, 211,200 acres.
1942 Wood River fire. Burned 250,000 acres,
ECOLOGICAL EFFECTS OF' FOREST FIRES IN ALASKA 17
1943 Two fires in the Fort Yukon district burned 224,000 acres,
and on the Black River 179,200 acres were burned over.
1944 Birch Creek fire. Burned 96,000 acres.
1947 Among the large fires in 1947 were the following: Salcha
River, 187,000 aeres; Dubli-Koyukuk, 192,000 acres; Kenai
Peninsula, 421,000 acres; Tazlina, 125,000 acres.
1950 Approximately 1,800,000 acres were burned in the region
east of Fort Yukon. ·
From the record it is clear that the forests of the Alaska interior
have been subjected to extensive and repeated fires for the past
several hundred years. Prior to the advent of the white man, the
natives and lightning storms started fires that spread over large
areas. There seems to be little basis for the view that the Indian,
prior to contact with white men, was prudent in his use of fire. Fires
were started intentionally by the Indians for signaling, and, to some
extent, to make hunting easier. Carelessness with camp fires and
smudge fires to combat mosquitoes was even more general and was
certainly a major cause of forest burning. __
With the advent of white men in the Territory near the end of the
19th century, fires became even more widespread than previously.
Particularly affected were those districts where gold placer deposits
were discovered. A map of the Fortymile Quadrangle prepared by
Barnard (9) shows that at that time (1900) only 3.6 percen~ (54 of
1,481 square miles) of the forest land had been burned over. Barnard
wrote, "The entire area of this quadrangle is fairly well timbered to
an altitude of 3,000 feet, save some areas which have been burned
over ... " Since then most of the region has been burned.
Railroad and highway construction also led to a rash of fires,
many of them among the largest the Territory has suffered.
The inroads that fire has made on the forest resources of the Alaska
interior, especially since 1900, may be traced to two attitudes that
are all too often encountered. The first is that fire is good for the
country. This view was formally expressed in a letter written by
an official of the Federal Government in 1915 (an exceptionally bad
fire year), as follows:_
I have heard men who have lived in Alaska many years, who
have the interest of the country at heart and who have no axe
to grind, make the statement that the best thing that could
happen to the Susitna and Tanana Valleys and similar locations
in Alaska would be for the government to employ a force of men
and at an opportune time in a dry season, burn off the whole
business.
In the Tanana Valley last summer there were many big forest
fires and I could but notice the attitude of the different people
I met remarking on it. Invariably the new-comer lamented
the fact that so much timber was being destroyed. The old-
timer said very little on the subject, but wore a smile of
satisfaction. · 1
The second attitude, which certainly contributes to the occurrence
of forest fires, is that they do no harm because the timber is worthless
anyway; it eannot be converted into cash at the present time nor
in the immediate future! Fires in "brush" (often stands of young
18 TECHNICAL BULLETIN 1133 , U. S . DEPT. OF AGRICUL'rUR~
sp ru ce or birch) are thought by many to be no cause for concern
becau se Lhe "brush" has no value. These attitudes are not shared
by the majority of Al askans. They are, however, expressed with
sufficient frequen cy to cau se co n cern for t he future of t he forest
resource.
The reasons advanced for in tentional burning of for est lands are
numerous but the most common are: (1) To increase moose feed,
(2) to inerease grass (chiefly Ca lamagro sti s canadensis ) for forage ,
(3) to kill mosquitoes and other insect pests , (4 ) to make prospecting
easier, and (5) to provide dead wood for fuel. U nintentional burning
occ urs chiefly as a resul t of general carelessness with fu·e. Camp fires
are l eft before they are extinguished, proper precautions are not taken
when clearing l and or disposing of debris along rights-of-way, and
smoking materials are discarded before they ar e out.
There is need for an enl arged program to make the people in the
Territory realize the value of the forest resource and appreciate the
damage to that resource by wildfires. The attitude that fires do no
harm to the forest b ecause "nobody owns it" should be r epl aced by a
realization that each fire reduces the wealth of the Territory and its
inhabi tants.
EFFECT OF FIRE ON FORESTS
Fires destroy forest co mmunities wholly or in part and usually
result in changes in co mposition. Usuall y the stands which follow
fires are composed of species different from those that previously
existed on the areas concerned . This may be good or bad, depending
on the utility of the stands that preceded and succee.ded t h e fires.
Climax types or co mmunit ies tend to be replaced, as a result of fire,
by types representing ea.rly successional stages. The new stands
are usually composed of fewer species, and as a rule , species l ess toler-
ant to shade than those d estroyed. The new forests tend to be essen-
tiall y even-aged. Pioneer spe ie s that invade areas swept by severe
fir es are fr equ ently shor lived in comparison with the long-lived
climax s pecies . Anot.her common feature of pioneer species is that
light easily disseminated seeds are produce d in tremendous numbers,
thereby fa vor ing t h e en t ry into denuded tracts.
Trees
In one r es p ect all forest trees in the Alaska interior are simil ar; they
are kill ed b)-severe fu·es. No species, with the possibl e exception of
balsam poplar, has bark sufficiently thick to withstand the high
temperatures that are generated, es p ecia l y around t he basal portions
of the boles. This is confirmed by the fa ct that living trees with fire
scars are uncommon. Only rarely are such trees encountered and
then almost invariably they are lo cated at the extr eme edges of
burned areas w here the intensity of the fu·e was low. Lacking also is
the capacity for crowns killed by fu·e to regenerate from dormant buds .
Further, most of the trees in the Alaska interior have very shallow root
systems, which are severely damaged, ;f not completely d estroyed b y
intense fir es . Ecological diff eren ces in the species occur, however, ~nd
some of them are important from the standpoint of reaction to burning.
ECO L OGICAL EFFEC'l'S OF FORES'l' FIRES IN ALA SKA 19
White Spruce
·whi te s pruce is very s usceptible t o destruction Ly fir e. The trees
hav e t hin , easily damaged bark and the liv ing branch es of t h e crown
commonly extend nearly to the ground . B eing very shallo>v rooted ,
whi te s pruce is severely affect ed b y slo wly burning, hot smf ace fir es
in t h e d ee p for est floor. A severe fir e will burn li v ing roo ts as large as
8 to 9 inch es in diamet er , l eaving only stubs attach ed t o t h e stumps .
JVIounds of spruce cone scal es 1 to 2 fe et in d ep th and 10 to 12 f eet in
diameter around the bases of occasional t r ees (fig. 5) provide fu el
for unusually ho t and p ersistent lo cal fir es. These mounds represent
cone cach es a nd f ee ding station s of r ed s quirrels (Tamiasciurus
hudsonicus). The h eavy grow th of beard li ch en s (Alectoria jubata and
Us nea comosa ss p. comosa chiefl y) on the trees in some stands is
prob abl y also a f actor favoring th e s pread of fir e .
F-47736 0
FIGUR E 5.-Accumulation of cone s cales around t h e base of an 18-inch d. b. h .
white s pruce is t h e r es ult of squirre l activit y . The d e bris favors d ee p b urning
at t h e bases of t r ees.
'iiVhite spruce is often at a d isadvantage in see di ng burned areas
b ecau se it do es not bear seed at as early an age as mo st of its asso ciates.
Furthermore , it i s often prese nt as an u n d er storYi under paper birch or
quaking aspen and hence is not cap a ble of seed production . There
are no data on the quantity of seed produce d b y white spruce in
Alaska. It is pres umed, however, t hat its seed production may be
similar to that of N orway spr u ce in northern Eur op e. Borg (16)
reported that in northern Europe a N orway s pruce for es t of full
density occasionally produ ces a seed fall of a bou t 4 million see d p er
20 TECHNICAL BULLETIN 1133, U. S .. DEPT. OF AGRICULTURE
acre. Kohh (73) stated that stands in Estonia having a crown density
of 60 percent produced about 3 million Norway spruce seeds per acre.
Hesselman (61) placed production in good seed years at around 2 to
4·million seeds per acre. It is possible that in favorable years, such
as 1951, production of white spruce seed in Alaska is at least as high as
the values cited for Norway spruce. Hesselman (61) pointed out an
interesting relationship between the occurrence of forest fires and
heavy seed crops of Norway spruce in Sweden. He found that warm
summers and abundant seed production occur together and noted that
forest fires are unusually common during warm summers. Thus,
during periods with warm summers, in natural forests undisturbed
by man, good seed years and extensive fire years tend to occur together.
Renvall (128), studying tree seed production at high latitudes and
elevations in Finland, concluded from his own studies and the work of
others that the viability, total production, and the seed year recurrence
interval decreases with increasing latitude or elevation. He reported
that in Scotch pine stands in about latitude 69°30' N., along the forest
limit, no reproduction had started in 60 years. The periods between
earlier seed years were established to have been about 90, 110, and
75 years or, in round. numbers, about every 100 years. Renvall also
pointed out that forest fires are a substantial evil in the far north where
seed years may occur very infrequently.
Infor~~tipn on the distances to which white spruce seed is dissemi-
nated in Maska is not available, but the average· effective distance is
probably much less than for paper birch, quaking a:spen, and balsam
poplar. Heikinheimo (58) suggested that Norway spruce seed may
often be scattered more than 300 feet from the parent trees and pointed
out the possibility of drifting much greater distances over crusted
snow. Holman (62), writing of conditions in the vicinity of Lesser
Slave Lake, Canada, concluded that the distance from spruce seed
trees where good reproduction can be expected (seedbed conditions
being favorable) is not over 4 chains (264 feet) to leeward; to windward
a distance about equal to the height of the seed trees .
. Although white spruce is shade tolerant, able to slirvive for long
periods under the shade of, and in competition with, overstory vege-
tation, it reproduces well on bare mineral soil following fires, and
makes good growth when exposed_ to full sunlight. Bedell (1 0)
stated that in Manitoba white spruce reproduction does not readily
establish itself on a heavy layer of litter and humus but will do so on
exposed mineral soil. He quoted unpublished data of Tunstell who
concluded that good white spruce reproduction occurred only on
burned areas. During the present investigation no instances were
seen where the ash residue inhibited germination and survival of
spruce. However, Heikinheimo (58) found that ash of birch in-
hibited germination of Norway spruce more than it did birch and
alder. His germination studies were made in soil to which varying
proportions of birch ash had been added.
The occurrence of spruce seedlings on rotting logs and stumps
under forest canopies has been observed repeatedly. Bedell (10)
mentioned such occurrence in forest stands in Manitoba and suggested
that "The presence of these seedlings on rotten logs is believed to be
due to the greater amount of moisture available." Melechow (92)
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 21
observed spruce seedlings developing on rotting logs in a forest on
the Dwina River in Russia. He noted that various investigators had
reported this as follows: Fabricius explained the occurrence on the
basis ·of good aeration of the root space from the side. Tschermak
mentioned the stable moisture supply and favorable level of nutrient
materials. Melechow suggested that the seedlings· on logs are l!3i;;S
subjeqt 'to injury from freezing and abrupt temperature ch~nges.
Thus seedlings on logs are in a more favorable microclirpJtt~.;.;!illan
those on the forest flo()r, ·1
': • ""''"'~15;~
Fires are especially 'destructive to white spruce seed for, unlike
black spruce, the cones:open at ~-!t!tll.l.:f~t~'~d the seed is disseminated.
Following a fire in white spni'ce, · r~~eheration of the species must
generally .come from seed blown in from adjacent unburned areas
although some seed may be supplied from previously unopened cones
th · ,aped destruction on the trees. Hesselman (61) said that some
N orwa · pruce seed in the forest floor may live through a forest
fire. This possibility exists also in white spruce but it is regarded as
unimportant.
In many localities white spruce appears to be a hardier species than
black spruce. This is contrary1:;to the views of many writers, but
agrees wit~h the observations of'Hustich .(6~). He pointed out that
where the'two species grow together white spruce always grows at
higher elevations and usually attains the form of a small, if stunted,
tree where black spruce only creeps on the ground, reaching approxi-
mately the height of the snow cover.
Black Spruce
Black spruce, when growing on upland soils, is as susceptible, or
more .susceptible, to destruction by fire than white spruce. The
factors which render white spruce liable to destruction apply equally
to black spruce. Extensive upland areas of black spruce have been
completely wiped out by fire. Even surface fires kill black spruce
and burn off many of. the roots, resulting in early wind throw of the
snags (fig. 6). On relatively wet lowland areas the lilmlihood of com-
plete destruction is much less. Here individual trees, and trees in
irregular groups or stringers, are likely to survive. This is important
because a continuing source of seed is thus provided for restocking.
Many, if not most, of the seedlings of black spruce on burned-over
areas originate from seeds present in unopened cones persisting on the
trees at the time of the fire.
Seed production in the 'species appears to be earlier and more
regular than in white spruce; total failures in seed crops seem to be
infrequent. Gilmore (48) in 1925 discussed conditions in Newfound-
land. He mentioned black spruce saplings bearing seed when 14
years of age. LeBarron (78) in Minnesota observed that there is
substantially less fluctuation in annual seed fall than in annual seed
production. Under normal conditions not all the seeds are shed from
black spruce cones for 2 to 3 years following maturity. As a result,
black spruce trees, at any given time, usually retain considerable
amounts of viable seed. This supply, stored on the trees near their
tops, is seldom completely consumed even in severe crown fires. The
22 TECHNICAL BULLETIN 11 33, U . S. DEPT . OF AGRICULTURE
F-477377
FrGURE 6.-W indt hrown black s pruce, 3 year s after a s urface fir e t h at killed t h e
t r ee3 and burned off rn any of t h e roots. Fire h azard will be high f or many
years. Kenai P e nins ula , 1950.
outer portions of the cone scal es may b e charred but the seed remains
v ia ble and, in large m eas ure, accoun ts for the abundant r egen eration
that usually develop s . The b ehavior of black s pruce following fir es
is analogous to t hat of certain other "fir e species," notably jack pine,
lodgepole pine, and pitch pine.
R eel squirrels cl evom great quantities of black spruce seed , clipping
off small branches with clus ters of cones from t h e upp er crown of
t r ees. This practice is r es ponsible for the pruned stem segm ents so
ch ara cteristic of black s pruce crowns. L eB arron (78) noted t his in-
flu en ce and mentioned t h e resul ting bunchy appearance of black
s pruce tops in Minnesota. The activity of reel s quirrel s in black
spruce for es ts is furth er indicated b y the oc currence of l arge mounds
of cone scal es wh ere cones h ave b ee n cached and the seeds eaten.
Black s pru ce, like white sp r u ce, is relatively to l erant of shade and
compe tition from other vegetation . However, regeneration is most
a bundan t and seedli ng growth is most rapid on mineral soil r eceiving
full , or n early full , sunlight. Under for est conditions black spruce
r egen erates r eg ul arly b y l ayering of basal branch es, producing a
groupwise distribution pattern , seen most dramatically from t h e air.
An interes ting habit of black spruce (and p erhaps also white spruce)
was describ ed b y Capps (28). On t h e north bank of t h e \Vhi te River ,
about 8 miles below Russell Gl acier, is a. bluff on which are growin g
spruce trees with storied root system s. Capps (2 8 ) explained that
spruce see dlings first d evelop shallo w, fiat root systems on b ec oming
establish ed in t h e moss-covered organic matter that overli es the min-
ECOLOGICAL EFFEC'l'S OF FOREST FIRES IN ALASKA 23
eral soil . As the mos s cover incr eases in thickness, the l evel of p enna-
frost rises and caus es t h e trees to d evelop n ew and higher sets of roots.
Trees with several sets of roots may b e seen . This f eature also has
been d escrib ed b y L eBarron (77) in the Lake States. H e regarded
the eventual r eplacement of old roots by n ew as a response to b etter
aeration n ear the s urface of the soil .
Paper Birch
Alaska paper birch appears to · b e the most common t r ee birch in
the interior of Alaska. On the K enai P eninsula , K enai paper birch
is the principal species. In view of t h e fact that t h e form er variety
is b y far the most wid es pread in i ts oc currence and t hat ec ologi cal
diff er e n ces b etween varieties are not p erceptible , no further distin c tion
will b e made . Young birch is readily killed b y fir e b ecause of t h e
r el atively thin bark. In l ater life the bark b ec omes thick er bu t it
is then also more flammabl e as it b egins t o exfoliate. The t inderlike
quality of birch bark is well known. However , more birch trees
s u rvive in burned -o ver areas than is the case wi t h white spruce.
The principal r eason is t hat the for es t floor under birch trees and in
birch stands is not ·a s d ee p as und er white spruce, so that s urface fires
generate l ess h eat and are l ess p ers isten t.
R egen era tion b y sprouting from root collars of fir e-k ill ed b ir ch es
i s fr equent in y oung stands, but l ess frequent in middle-aged a nd old
stands. The sprouts aris e from dormant buds around the base of the
stump and contribute to r estocking . R egenera tion from t his source
is not, howev er , as important as seedling reproduction.
Birch es produce seed at an early age; H eikinheimo (58), in F inl and,
r eported seed produced b y birch sprou ts 10 years of age. Kohh (73)
investigated seed production in B etula verrucosa and B. pubescens in
Estonia and stated that in a good seed year a 70-year -old stand on site
I produced from 110 to 244 million see d s p er acre (average 200 million ).
In his studi es of B etula alba in Finland , Kujala (7 4) reported t hat
trees burned sufficiently to kill the cambium compl etely around t h e
base still r etained a mantle of foliag e and y ielded an excess of ripe
seed except on t h e lowest branch es . If this habit is general in birch
it must have an important influen ce on reproduction following fir es.
Birch seed is light and readily diss eminated b y t h e wind; thus t h e
species is a rather highly mobile pioneer. Mineral s oil seedbeds and
full sunlight provide favorabl e conditions for initial establishmen t
and subsequent rapid growth (fig. 7 ). Splendid d en se stands of
w ell-formed trees fr equently follow fir es if adequate supplies of see d
a r e availabl e.
Quaking Aspen
Quaking aspen is killed b y hot fir es bu t in pure stands the fir es are
characteristically ligh t. Conditions for d ecomposition of litter under
aspen stands are relatively favorabl e; t h e l eaves tare no t particularly
resistant to d ecay, and stand d ensity is generally low enough to permit
adequate precipitation and sunlight t o r each the ground. A s a result,
the accumulation of for est floor material i s u sually to o ligh t to carry
a hot, p ersistent fir e ,
24 'l'ECHNICAL BULLETIN 113 3, U . S. DE PT. OF AGRICULTURE
F-477362
FIGURE 7.-Dense growth of Alaska paper birch seedlings on mineral soil in the
Goose Ba.y-Knik a r ea.
After the great burn of 1947 on t h e Kenai P eninsul a, g r ee n stands
of as p en frequently rem ained , s urrounded b y areas in which t h e s pruce
was co mpletely killed (fi g . 8). This does not m ean that aspen stands
are immune t o damage b y fir e. Surface fir es do pass through t h e
stands and trees are killed but seldom is d estru ction as complete as
in s pruce or birch. Stump sprouts from fir e-kill ed aspen are unco m-
mon bu t roo t su cker s ar e extrem ely a bundant. Areas t h at s up-
por te d as p en prior to a fir e are almost certain to b e r egenerated with
t h e sam e sp ecies as a result of root suck ers alo ne. R eproduction is
striking in tracts where a severe fir e has swept through a spru ce for est
with occasio nal as p en trees. Around the b ase of each d ead aspen
tree, roo t s u ck er s arise abundantly, covering roughly circular areas
whose diameters depend on t h e siz e a nd roo t s pread of the killed tree .
I n t he L ake States i t was found that burning in uncut stand s of
aspen stimulated h eigh t growth of as pen root s u ck ers (160 ). In
the fir st year after burning the average h eight of root suckers on burned
ar eas was 2.43 fe et, on unburned areas 1.97 f eet.
Seedling reproduction of aspen is als o common. Seeds are borne
in tr emendou s numbers a nd t h ey ar e admir ab ly adapted for wide··
s pread dissemination by wind . Kittredge and Ge vo rkiantz (71)
indicate t h at t here are 2.5 to 3 million as pen see d s per pound . R eim
(127) cal cul ated that in northern Emope during good seed years
aspen stands produce 162 to 202.4 million seeds per acre (excluding
those d estroyed by insects). A singl e g ood t r ee may produce about 54
million seed s . Quaking aspen is a pioneer s p ec ies . I t is intol erant of
shade, char acteristically d evelops in even -age d stand s, and find s
mineral soil exposed to full s unligh t favorable for establishment and
s ubsequ ent devel opment,
:IDCOLOGICAL EFFEC'l'S OF FOnES'!' FinES IN ALASKA 25
F -477363
FIGURE 8.-A 65 -year-old quaking aspen stand. The dominants are 6 to 11 inches
d. b. h. and 65 feet tall. A light surface fire killed all u nderstory white spruce
in 19 47. Kenai P eninsula, 1950.
Balsam Poplar
Balsam poplar is prob ably more resistant to destruction by fire
than any other forest tree in t he in terior of Al aska. B ark thickness,
near t h e base of the bol e, is often 4 or more incpes on mature trees .
As in aspen stand s, surface fires in the balsam poplar type tend to be
light because of t he r el atively thin accumul ation of fortlst -floor
m ateri al.
R egeneration by roo t su cker s is common in balsam poplar stands
through which fire h as passed. Seedli ng r eproduction is also abund-
26 TECHNICAL BULLETIN li33, U. S. DEPT. OF AGRICULTUR~
ant whenever mineral soil has been exposed and a source of seed is at
hand. Like aspen, balsam poplar is intolerant to shade and produces
tremendous quantities of seeds that are easily and widely disseminated
by wind.
The species is normally regarded as a pioneer tree on recently
deposited alluvium along streams and river valleys subject to overflow.
It is also present on upland areas where, as a result of fire, exposed
mineral soil has provided an opportunity for the seeds to germinate.
In fact, occurrence of balsam poplar in anything approaching pure
stands on upland areas is practically contingent on the occurrence of
fires.
Subordinate Forest Vegetation
Shrubs
Shrubs, because of their low stature and small stems, are especially
liable to destruction by fire, AB a group, however, they have a rather
remarkable capacity for vegetative regeneration through sprouts aris-
ing from stem bases and roots. Much of the reproduction following
fires is vegetative. The establishment ofshrubs with fleshy or pulpy
fruits is relatively slow on burns because these plants are dependent on
animals for seed dispersal (7 4, 117). Animals are not abundant on
burned areas, at least for several years after the fire.. On the other
hand, the willows, which form the largest single group of shrubs in
Alaska, produce minute hairy seeds admirably. adapted for wind dis-
semination. Furthermore, they produce seed at a very early age;
sprouts 2 to 3 years of age bear catkins. Therefore, the willows are
usually well represented in the seedling regeneration of burned areas.
Brief notes concerning the ecology of certain species follow:
Arctostaphylos u·va-ursi reproduces following fires from protected seeds in the
forest floor, as does Empetrum nigrum (134). A. uva-ursi reproduces more
regularly than E. nigrum, presumably because of better germination of the seed.
Kujala (74) included Arctostaphylos in the group of plants incapable of vegetative
reproduction from underground parts; in his opinion it reproduces mostly around
the edges of spots where burning was deep, to mineral soil.
Empetrum nigrum reproduces from seeds that are buried in the forest floor, thus
escaping damage by fire (134). Germination is slow and erratic, with the result
that the seedlings come in gradually over a period qf 3 to 5 years. Aaltonen (2)
regards E. nigrum as a species that is very susceptible to fire damage and spreads
only slowly. To him it appeared that at least 20 to 30 years were required after a
fire for E. nigrum to regain normal density.
Following fir~!) Ledum palustre regenerates from rootstocks, according to
Sarvas (134). 1\.u~ala (7 4) also listed it with species possessing underground
reproductive organs. Townsend (156) quoted from George Cartwright's Labrador
Journal, published in 1792, to the effect that when old spruce forests were burned,
Indian-tea [Ledum groenlandicumJ was generally the first species to reappear.
Vaccinium uliginosum reproduces after fires from protected rootstocks (134).
Vaccinium vitis-~daea also reproduces from rootstocks (2, 7 4, 134).
Herbaceous Plants
It is impossible to generalize on the effects of fire on herbaceous
plants because they differ so greatly in life form, seed habits, and other
ecological characteristics. Regeneration in many instances is vege-
tative, particularly in those species that appear earliest after fires.
Reproduction by see'd is, however, more general and more important.
Many, if not most, of the species that invade burned areas are those
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 27
whose seed is easily disseminated by wind. In studies of burned
areas on two islands in the archipelago east of Helsinki, Pettersson
(117) noted that "the anemochores are represented in a manifest
multitude." Vogler (162) investigated the alpine plants in Switzer-
land and concluded that the younger a vegetation community the
greater the percentage of plants whose seed is wind disseminated. On
recently burned areas the scarcity of plants with fleshy fruits, noted by
Kujala (7 4), is explained by Pettersson (117) as resulting from the fact
that animals are not attracted to burned areas. Plant species that
produce large quantities of easily disseminated seed at an early age
have an advantage over those not possessing these characteristics.
Seed supply is an important consideration in the revegetation of
burned areas. Failure to evaluate the quantity of seed produced, its
adaptations for dispersal, and the efficiency of the agents of dispersal
often leads to erroneous conclusions on the significance of site factors.
Absence of a species in a given area or at a given spot is not direct
evidence that the habitat is unfavorable.
Species invading recently burned areas tend to be those which
develop best in full light. Often they are characterized by very rapid
growth.
Germination of seed and survival of seedlings is highest in areas or
spots where mineral soil has been exposed. On the other hand,
species that reproduce vegetatively from underground parts tend to
come in best on areas where the fire burned less intensely. These
differences in species, together with the heterogeneity of the pattern
of burning-often more intense burning under spruce trees than in the
intervening space between spruce trees-result in a mosaic of vege-
tation. This mosaic is evident, on a grand scale, in the pattern of
broad forest types and it is also evident, on a minor scale, in the
occurrence of species and group societies of the subordinate vegetation.
Brief notes as to the ecology of certain herbaceous plants follow:
Calamagrostis canadensis is widely recognized as a species that develops abun-
dantly in burned areas. Establishment of Calamagrostis following forest fires has
been reported frequently, especially by explorers or hunters who employed pack
animals.
Festuca ovina reproduces after fires from basal buds as well as from seed (134).
Epilobium angustijolium, the common fireweed of the north, has been referred to
by Graff (51) as a pyrophilous plant. It grows in great numbers on practically all
burned areas in the interior of Alaska (fig. 9). Skutch (146) quoted an old observa-
: tion by Irmisch, "The primary as well as the secondary roots of the young seedlings
develop buds freely, which sometimes give rise to plants in the succeeding year.
The shoots from old roots may grow so fast that they bloom within a month. The
roots are undoubtedly capable of persisting for several years in a dormant con-
dition until the environment changes by clearing or burning the woods." Summer-
hayes and Williams (149) noted that the species has extensive roots usually capable
of producing adventitious aerial shoots. In addition to this remarkable capacity
for vegetative reproduction, Epilobium angustijolium produces an abundance of
seeds which are easily and widely disseminated by wind. The species is regarded,
by Hesselman (59) and others, as a nitrate plant, indicating active nitrification in
the soil of burned areas. Sarvas (134) noted that reproduction is particularly
abundant on spots that have been burned deeply, exposin'g mineral soil.
Linnaea borealis is completely destroyed by fire, acc6rding to Sarvas (134).
Here and there unburned spots serve as centers from which the plants spread.
Lycopodi-um complanatum has underground stems and reproduces from these
after fires (7 4, 134). L. annotinum has shallower underground stems; consequently
it is less frequently encountered where burning has been deep.
Species of Pyrola are included by Kujala (7 4) in the group of plants that are able
to reproduce from underground parts~
28 TECHNICAL BULLETIN 11 33, U. S . DE P 'r . OF AGR I CULTURE
F -47736 4
F rauRE 9.-A 110-year-old stand of black spruce 3 year s a fter a fir e. The vege-
tation is la r gely fir e weed (Epilobium angustifolium). Kenai P eninsula, 1950 .
Mosses occ ur ab un d antly in t h e forests of interior Al aska. They
fo rm a ch aracteristic stratum in nearl.Y ever y stand and must b e
r egarded as an integr al p ar t of t h e forest commun i t ies. P ersson (1 14)
calcul ated t h at 85 .5 percent of t h e 592 s p ec ies of bry ophytes k nown in
t h e Alaska-Y ukon r egion ar e als o found in Europe. Their impor t an ce
is d u e princip ally to the fact t h at t h ey influ en ce soil temperature (and
h ence t h e p os i t ion of t h e p ermafrost), s oil moisture rel ations, seedbed
conditions, s oil erosio n, and h y drolo gic rel atio ns . The u sefulness of
mosses to wildlife is very limited (9 1 ). Cap sules ar e reported t o b e
eaten by t h e spruce grouse (Canachites canadensis) and by mice and
l emmings; t h e plants ar e u se d b y s ome birds and m ammal s in nes t
building.
Mosses reproduce by s pores, bu t probably most of the r egener atio n
after f orest fires is vegetative . Brief notes concerning t h e r eaction
of cer tain moss sp eci es to fir es f oll ow :
Ceratodon pm·pU?·eus is a fi r e species in t h e sen se that it com es in very ab un-
d antly after fir es. Sum merhayes a nd W illiam s (149) r epor ted t h e appearan ce
of Ccratodon in quantity 3 yea rs a fter felli ng a nd burning in a pine fo r est in Eng-
l and. Sku tch (146) fo u nd it a n ab un d ant species 4 year s after a fi r e on Mt.
D esert I sland, Maine. Sarvas (184) noted t h at it repr odu ces by rhizoids on
burns. It also r ep roduces by sp or es at an early age and may thr ou gh them
grow a complete cover in as little as 5 years.
Dicranum ber geri, D . fuscescens, and D . maj1ts r epr odu ce vegeta t ively a fter
fires, according to Sar vas (184), b u t do n ot attain g r eat impor tan ce on b urned
a r eas.
P leurozium schTe be1·i is a lm ost completely k illed by fires, b u t u s u a lly so m e
parts capable of rep rod ucing remain. Sar vas (184) stated t h at soil con ditjons on
burns are such, h owever , that these remnants u sually d o not regenerate. Only
ECO LO GICAL EFFECTS OF FOREST FIRES IN ALASKA 29
afte r 3 0 to 40 years when a closed forest s tand has d e v el oped does the species
begin to a ssume its previous importance.
Pohlia milans is said b y Sarvas (134) to r egenerate by rhizoids after fir es and to
produce s pores in about 5 to 10 years.
Pol ytric hu m commune enters burne d areas early and may r e place speci es s u ch
as Ceratorlon pu1·pw·eus. Skutch (14 6) r e ported P . comm1me a s l ocally ab undant
in mois t s pots in a burn in Maine one year after a fire. Four years after the fir e
it had s pread over considerable a r e as , r e placing the liverwort Nlm·chantia poly-
mO?·pha. Comparable r eplacement of 1\llaTc hanlia by Pol ytric lwm was note d in
England b y S ummerhayes and 'i'Villi ams (149).
Polytrichum juniper i nwn and P. piliferwn hav e dee ply p e netrating r hi zo ids,
\Yhich , followin g fir es, s erve to r e produce the s p e ci es (74, 1 .'3 1,.). Sarvas stated
t hat s pec ies of Polyh·ichnm a r e mo t characteristic on areas 10 to 20 year s afte r
a fir e ; th ey s uppress the earli er a ppear in g s pec ies of Cer alodon a nd Poh!ia and, in
t urn , a r e them selves late r s uppre:;sed by oth e r mosses a nd liche n s . Aalto ne n (2),
S kutch (1 1,6), an d Hus tich (6.5) a ll regarde d t hese s peci es of P o/yh·ichmn a s
pioneer s o n burned areas .
1\llm·chantia polym01·pha is a live rw01·t b ut fo r conve nience it is mention ed at
this point. It is s o common on d ee pl y burn ed areas that Graff (.52) r eferre d to
its p y rophilous character aud Sar vas (1 84) referre d to it a s the class ical fores t
fir e li verwort. M. polymoTpha e nter s burned areas whe r e mineral soil has been
exposed, appearing within 1 to 2 year s after the fire . The early e ntry of the
s p e ci es and its rapid and extensive s pread have bee n noted by Summerhayes and
Williams (149) and Benson and Blackwell (15) in England, by Skutch (11,6) in
Maine, by Graff (51 ) in the Rocky Mountain region, by Torrey (151,, 156) in
New J ersey and Virginia, and b y others . It is s ucceed e d, within a f ew y ear s,
by m osses and peltigeras .
Lichens form a large group of plants, a number of which a r e highly
important as food for caribou (Rangifer arcticus) and r eindeer (Ran giJ er
t.arand·us ). Lichens are u s ually d estroyed whenever a s urface ilre
sweeps over an area. The gen er al situation has been stat ed b y L ynge
(84), a close student of th e group , as follow s:
If a lich en vege tation has b een disturb ed or clriv eD away from
its natural habitat it will in many cases r equir e a long time
before it again can cover i t . This is best seen aft er fore s t fir es .
I h ave seen gaps mad e b y old fore st fire , 50 year s or more old ,
where the range of t h e fir e cou ld be traced on the li chen vegeta-
tion, Olaclon i a alpes tris was more scarce and l ess d eveloped there
than outside the range of the fir e . Even quite small fir e gap s
require an extremely lon g t ime before they will be cover ed wit h
the sam e li ch ens again. I have seen ex p erimental fi elds, 1 s quar e
m eter large in fin e Cladonia .fields wh er e no t r ace of Cl ado nia
alpes tris was visibl e 5 to 6 years after the fir e, and Lapponian
tent fire -places so old t hat even their smrounclin g st.ones were
s unk into the earth wher e the place was reeogniz;ab l e on t h e
vegetation. The original li eh en co ve r was g one, sometimes
r eplaced b y mosses or b y other lichens, as P elti gera s puri a and
P. a.phthosa, even if the near est s tation for t-hese plan ts was far
dist ant .
Kujala (74) expressed the v iew that fu·e Las a more d estructive eff ect
on lich ens and mosses than on t.he vascular plantfl .
R eproduction in lichens may b e either sexual m asexual. However ,
production of soredia and fragm entat ion appear to b e th e mo st
common m eans of reproduction. A cc ording t o P er ez -Llano (11 3) a
consid erable number of folios e lich en s, as well as a few cru stose and
fruti cos e s p ec i es, seldom produce apothecia and spores . Those
species which appear earli est on bmned areas are generally of low
30 TECHNICAL BULLETIN 1133, U.S. DEPT. OF AGRICULTURE
stature and probably regenerate from subterranean parts and bits of
unburned thallus. The taller fruticose lichens in the reindeer lichen
group are likely to be exterminated by fire, and their return is generally
slow.
Hustich (65) stated that in the lichen woodlands of northeastern.
Canada complete recovery of the lichen cover after a fire requires at
least 40 years. He cited estimates from investigators in other coun-
tries as follows: Itkonen, 40 to 50 years; Manning, ;jQ years; Sarvas,
30 to 40 years. Aaltonen (2) stated that in Finland lichens were still
not abundant 20 to 30 years after a forest fire. Tengwall (152) meas-
ured the rate of growth of the reindeer lichens and reported that the
rate of development of small plants is about the same as that of large
plants. Only when the lichens approach their maximum size does
growth slow up. He noted that certain individual large lichens did
not grow at all during the years that he carried on his observations;
they had reached their maximum size of about 1.8 to 2.6 inches (45
to 65 mm.).
The ecology of lichens, particularly as it relates to the effects of
fire, is not well understood. Considerable information has been
obtained by investigators in northmn Europe, however, and an
attempt has been made to summarize this for certain species.
Alectoria jubata and other beard lichens which hang in masses from the branches
of trees are readily flammable when dry; they undoubtedly contribute to the
spread of fire. ··
Cetraria islandica is a heliophilous species, especially abundant in dry situations
(84). It is destroyed by fires and occurs almost exclusively in unburned areas
(134). C. islandica grows more rapidly than Cladonia alpestris (84).
Cetraria nivalis, usually .associated with C. cucullata was regarded by Lynge (84)
as growing more rapidly than Cladonia alpestris.
Cladonia alpestris is thereindeer lichen of the Scandinavian countries and grows
very slowly (84). Sarvas (134) reported that 10 years after a fire numerous
small plants may be encountered but that they attain full growth only after
30 to 40 years. Tengwall (152) calculated that 30 to 35 years were required
for plants to develop to maximum size. Lynge (84) reported that the len,gth
of time for recovery estimated by farmers and Laplanders in ·Norway varies from
10 to 40 years. He remarked, "We do not know the time for full development
but it is hardly possible to mention a lower figure than 25-30 years under favor-
able circumstances."
Cladonia bellidiflora, according to Sarvas (134), attains greatest abundance
20 to 30 years after fires; it regenerates after fire from underground parts and
unburned bits of thallus.
Cladonia cariosa, according to Sarvas (134), attains greatest abundance 20 to
30 years after fires. Regeneration following fires is similar to that in C. bellidi-
flora. ·
Cladonia coccifera is generally one of the first lichens to appear on burned
areas (2). Lynge (84) regarded it as a rapid grower, having seen podetia nearly
0.6 inch (15 mm.) with a small corona of red apothecia in plants not over 3 years
old, Sarvas (134) reported that it attains greatest abundance 20 to 30 years
after fires. Regeneration is similar to that in C. bellidiflora.
Cladonia cornuta, taller than C. coccifera, C. cariosa, and C. bellidiflora, is
regarded by Sarvas (134) as more likely to be exterminated by fire. Aaltonen· (2)
stated that it is one of the first lichens to appear on burned areas but Lynge (84)
regarded it as a forest lichen.
Cbdonia crispata was considered. by Lynge (84) as chiefly a forest lichen.
Cladonia deformis was reported by Aaltonen (2) to be one of the first lichens to
appear on burned areas. Sarvas (134) found that greatest abundance was
attained 20 to 30 years after a fire. Regeneration is similar to that in C. bellidi-
flora.
Cladonia degenerans attains its greatest abundance some 20 to 30 years after
fires (134). Regeneration is similar to that in C .. bellidijlora.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 31
Cladonia furcata var. racemosa is taller than C. cocci/era, C. cariosa, C. deformis,
C. degenerans, and C. bellidiftora. Fire is more likely to exterminate C. furcata
than the shorter species of Cladonia (131,.).
Cladonia gracilis was found by Aaltonen (2) to be one of the first lichens appear-
ing on burned areas. Lynge (84-) viewed it as primarily a forest plant.
Cladonia rangiferina, one of the reindeer lichens, is readily destroyed by fire.
Sarvas (134-) reported that 10 years after a fire numerous small plants may be
found but that they attain full growth only after 30 to 40 years. Tengwall (152)
calculated that 15 to 20 years were required for development to maximum size.
Lynge (84-) pointed out that the species has rather high light requirements.
Cladonia sylvatica is also a reindeer lichen. Some authors have interpreted e syl1Jalica broadly, evidently including much material that could be referred
to C. mitis. Sarvas (131,.) noted that 10 years after a forest fire numerous small
plants may be present but that they attain full growth only after 30 to 40 years.
Tengwall (152) calculated that the maximum size was attained in 20 to 30 years.
Lynge (84-) suggested that regeneration of C. sylvatica is easier than for C. alpestris
because it reappears more quickly after great forest fires. As in the case of C.
alpestris, Lynge wrote, "We do not know the time required for full development
but it is hardly possible to mention a lower figure than 25.,-30 years under favor-
able circumstances."
Hustich (65), in discussing conditions in. Labrador, regarded Cladonia mitis
as the first reindeer lichen species to invade burned lichen forest. He reported
that near the coast of James Bay, C. mitis was only 1 inch high in a prime dwarf-
shrub forest that had been burned 25 years previously. It appeared to Hustich
that C. mitis has slightly broader ecological amplitude than the other reindeer
lichens, often penetrating into dry tussocks on bogs.
Cladonia uncialis is one of the reindeer lichens, according to Sarvas (131,.).
He stated that 10 years after a forest fire numerous small plants appear but that
they are not full grown until 30 to 40 years after the fire. .
Cladonia verticillata attains greatest abundance 20 to 30 years after a fire (131,.).
Following fires this species may regenerate from underground parts or unburned
bits of thallus. ·
lcmadophila ericetorum tends to be concentrated on organic substrata-decay-
ing wood and balls of humus material bared by forest fires (131,.).
Nephroma arcticum reaches its best development in the forest (81,.). Sarvas
(134-) regarded it as comparable to peltigeras from the standpoint of occurrence
and reproduction following fires. ·
Peltigera aphthosa can endure more shade than most other lichens (84-). Sarvas
(131,.) pointed out that the habit of growth (over the moss and lichen cover)
renders this plant liable to destruction by fires. In burned areas it occurs on the
most lightly burned spots or areas missed by fire and from these spreads out
rather rapidly. ·
Stereocaulon paschale requires about 15 years to attain maximum size (152).
Lynge (84-) referred to it as fast growing; it can produce full-grown thalli in 5 to 6
years. Sarvas (134-) noted that S. paschale and S. tomentosum grow close to the
ground. The relatively strong principal axis is partly embedded in the soil and
after forest fires ti).is may remain undamaged, thus serving for reproduction.
Succession Mter Fire
Forest vegetation development following fires in the interior of
Alaska is neither a completely fortuitous, random process nor is it an
invariable, highly orderly process closely directed by a mysterious,
beneficent "Nature." Elements of the fortuitous do exist but there
are also elements of order. In this respect, conditions in the forests of
the Alaska interior are not fundamentally different from those in the
forests of regions to the south. The writer does hot accept the view
that ecological principles that apply ih the tem'perate zone are not
applicable in the forests of the North. The colloquial dictum that
"Alaska is different" need not cause the forest ecologist to discard his
working tools developed in lower latitudes.
349169-56--3
32 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICULTURE
In this study it was convenient to employ the concept of climax
vegetation in the sense of self-perpetuating, terminal plant commu-
nities of considerable stability. Two categories of climax vegetation
are distinguished-climatic and physiographic. The climatic climax
forest is regarded as the terminal stage of successional development on
moderately well-drained uplands and the physiographic climax forest
is regarded as the terminal stage on poorly drained, relatively cold
areas. From the standpoint of stability there is little difference
between a climatic climax and a physiographic climax-for practical
purposes, both may be regarded as self-perpetuating, terminal com-
munities. There is no implication that climax forests are desirable
and that subclimax forests are undesirable. Utility must usually
determine the vegetation type most desired; in some circumstances
this type will represent an early or intermediate stage of succession
and in other instances it will represent the terminal stage, here called
the climax. ·
In the following pages the plant communities encountered in the
forested regions of the Alaska interior will be described and the course
of succession indicated.
As an aid to understanding the succession leading to climax forest
communities and the retrogression that follows repeated fires in the
various forest types, a schematic representation is shown in figure 10.
This figure represents a generalization of the course of events observed
in the field. Aberrant successional stages and retrogressive changes
may occur.
Recently Burned Areas, Currently Regenerating
Some areas were burned so recently that they could not be assigned
to specific forest types or plant communities. They are in a stage of
very rapid change, with the site only partially occupied and with new
plants entering each year .. These burns usually were less than 10
years old.
The two most important conditions that influence development of
seedlings in recently burned areas appear to be (1) the presence of
viable seed, and (2) exposed mineral soil. As mentioned earlier, many
of the pioneer species produce abundant seed that is readily dissemi-
nated by wind. The exposure of mineral soil is important from the
standpoint of seed germination and seedling survival and growth.
Mineral soil provides a more favorable seedbed than charred organic
matter because the former has (1) a more stable moisture supply, (2)
somewhat lower surface temperatures, and (3) a greater supply of
readily available plant nutrients. The great importance of mineral
soil seedbeds for seedling establishment was observed repeatedly. In
the area swept by the gre~t fire on the Kenai Peninsula in 1947 the
majority of seedlings developed where the fire had burned deeply,
exposing mineral soil. Seedlings of all species were scarce in situations
where the forest floor material was not appreciably reduced by the
fire and the surface only charred.
The extent to which mineral soil is exposed by fire will, of course,
vary with time and place. In the recently burned spruce areas
examined in the course of this investigation, the proportion of mineral
soil surface exposed averaged about 85 percent but varied from about
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 33
WHITE
SPRUCE-
ASPEN
SPRUCE-
BIRCH
WHITE SPRUCE
CLIMATIC CLIMAX
WHITE
SPRUCE
SPRUCE-
POPLAR
OR BLACK SPRUCE
PHYSIOGRAPHIC CLIMAX
ON POORLY DRAINED
AREAS
BLACK
SPRUCE
j___ t . ~,J,:. t J ·~~iF~~
ASPEN
ASPEN
BIRCH
WHITE
SPRUCE POPLAR
A single severe · fire
BIRCH OR ASPEN, BIRCH,
ASPEN POPLAR,BLACK
SPRUCE, OR
WHITE SPRUCE
POPLAR
ULTIMATELY HERBACEOUS (FIREWE.ED-GRASSl
OR SHRUB COMMUNITIES
BLACK
SPRUCE
BLACK
SPRUCE
FIGURE 10.-Changes in forest types following fire.
5 to 100 percent. Burning tended to be more intense on ridges than
in valley situations, and slopes with south or west exposures com-
monly had more mineral soil exposed after a fire than did slopes with
north or east exposures. Fires are often unusu
1
dJly severe on rocky
slopes or ridges.
More noticeable than any influence of topography or exposure,
however, was the effect of the trees themselves on the pattern of
burning in the forest floor. This influence has been mentioned by
Kujala (7 4) in his investigations of the effects of forest fires in Finland.
34 TECHNICAL BULLE'l'I N 113 3, U. S . DEPT. OF AGRICULTURE
He stated (74, p. 35) that burning was more intense und er the trees
than in the spaces between them. In the current study it was
repeatedly observed that, in practically all fires , burning was deepest
and most intense under trees; the periphery of a given deeply burned
area approximately coincided with the crown projection of the tree
concerned. This may be due to the following: First, and probably
most important, is the fact t hat spruce trees have long , if narrow,
crowns which must intercept much of the precipitation ·which fall s in
light rains or in light snow storms . The driest places in a spruce
for est must be immediately beneath t h e tree crowns. A second factor,
which is l ess important but significant, is the accumulation of co n e
scal es frequently seen around the bases of spruce trees in stands of
seed -bearing age (fig. 5).
In paper birch, quaking aspen, and balsam poplar stands burning
is usually l ess intense than in spruce and consequently l ess mineral
so il is eA.rposed.
Density of vegetation on recent burns increases with the passage of
time. The species that enter earliest spread vegetativel y and by
seed and are suppl emented by later entrants.
Spruce, paper birch, quaking aspen, and balsam poplar reproduction
appears in burned areas within one year after a fire. On 21 areas
examined, the average number of spruce, paper birch, and Populus
species (quaking aspen and balsam poplar) s~ed ling s and sprouts per
acre was 2,000, 8,000, and 5,000, respectively. Stocking with spruce
ranged from none to 12 ,000 seedlings per acre; 25 percent of the plo ts
contained no seedlings. In paper birch, stocking ranged from none
to 131 ,000 per acre; 30 percent of the plots bore no seedlings or sprouts
of the species. Populus seedlings and sprouts ranged from 500 to
18 ,000 per acre and were absent on only 5 percent of the plots. These
areas had been burned from 1 to 10 years previously . With an average
of 15,000 tree seedlings per a cr e already present and with the process
of reg en eration continuing, n ew forest stands will follow those de-
stroyed. This conclusion is substantiated b y the fact that in the
interior of Al aska there are practically no barren areas resul ting from
single burns.
Vegetative reproduction following fires is l acking in the spruces,
occasional in y oung and middle-aged paper birch, but very abundant
in quaking aspen and balsam poplar (fig. 11). A series of milacre
plots were examined along a transect 165 f eet in length, arranged so
t hat it sampl ed the reprodu ction established under a fire-kill ed aspen
13.1 inches in diameter . Three years had el apsed since the fiTe
occurred . The total numb er of seedlings and root suckers was 59,350
p er acre, of which 36 ,230 were root suckers and 23,120 seedlings. All
root suckers exc eeded a h eight of 1 foot and 9 p ercent of them h ad
attained a height of 2 .5 to 6.0 feet. The most heavily stocked milacre
s upported 80 root suckers and 54 seedlings, the equivalent of 134,000
stems per acre (fig. 12).
The spruces concerned are the white spruce, Porsild spruce, and
black spruce. Tree birches are principally Alaska paper birch and
Kenai paper birch. Of the poplars, quaking aspen is by far the most
abundant, being present on nearly all plots. B alsam poplar is the
co mmon cottonwood of the interior; black cottonwood is a coastal
BCO LO GICA L EF'FEC'I'S OF' FO~ES'l' FIRES IN ALASKA 35
F-477374
FIGURE 11 .-A 110-year-old stand of black s p ruce with occa-ional quaking a s p e n,
burne d in 1947 . N ote abundant gr owth of aspen root s ucke r s aro und fire -
kill e d a s p en t r ee. K enai P eninsula, 1950.
14 0
------
I
~I '. I .I
79.2 66.0 52.8 39.6 26.4 ~0 __ '3-.2~ 26.4 39.6 52.8 66.0 79.2 0
DISTANCE FROM BA SE OF FIRE-KI LL ED ASP EN (FEET)
FIGUR E 12.-Aspen reproduction around a 13 .1-inch fir e -ki ll e d a s p e n . Ba:o;e d on
· a transe ct 3 year a after t h e fir e . K e nai P e ninsula.
I
sp ec ies of limited occmrence on t h e Kenai P ef1insula, and p erhaps
in the l ow er Su sitna River vall ey, bu t is unknown throughout t h e
interior prop er .
Shrub reproduction consists predomin antly of ·willows which, in
their early years, are prac tically impossible to identify . Those
36 T·ECHNICAL BULLETIN 113 3, U. S. :DEPT. OF AGRICULTURE
represented most abundantly in unburned areas adjacent to recent
burns were Bebb willow, Scouler willow, littletree willow, and Barclay
willow. Stocking with willow reproduction averaged, for all plots,
5, 700 seedlings and sprouts per acre, the numbers ranging from none
to 53,000. · W'illow reproduction was lacking on 25 percent of the
plots. Sprouting from fire-killed young willows is_ abundant but old
suppressed willows produce few sprouts. Of the other shrubs, Cornus
canadensis, Rosa acicularis, and Vaccinium vitis-idaea are the most
abundant, being found on nearly all recently burned areas. Occa-
sional are Ledum palustre ssp. decumbens, L. palustre ssp. groenlandi-
cum, and Vaccinium cespitosum.
SHRUBS, RARE
Alnus sinuata
A. tenuifolia
Arctostaphylos alpina ssp. rubra
A. uva-ursi
Empetrum nigrum
Potentilla fruticosa
Ribes triste
Shepherdia canadensis
Vaccinium uliginosum
Reproduction of shrubs other than willows in recent burns is for the
most part vegetative, with some seedlings developing from seed stored
in the forest floor. -
Grasses enter recent burns promptly, usually appearing within 1 to 2
years after a fire. Three species, Agrostis scabra, Calamagrostis
canadensis, and Festuca altaica, predominate on areas recently burned.
These species have a relatively high frequency of occurrence, but the
density of their cover is low, generally less than 10 percent. Other
species occasionally encountered, and entering after the third or fourth
year following the fire, are Arctagrostis latifolia, Calamagrostis pur-
purascens, and Poa pratensis.
Grasslike plants appear in sparse number 3 to 4 years following
fires. Carex concinna, C. media, C. rossii, and Juncus castaneus are
present.
A number of species of £orbs are represented. Epilobium angusti-
jolium is the most abundant plant, often attaining densities of cover
of as much as 50 percent. It is present in practically every area that
has been recently swept by fire. Species of Lupinus, chiefly L.
polyphyllus, are likewise abundant but density of cover usually is not
more than 5 percent. Linnaea borealis var. americana is widely
distributed but densities are usually very low. Polemonium caentleum
ssp. villosum and Pyrola secunda are common.
Achillea borealis
FoRBS, OccASIONAL TO RARE
E. pratense
Aster sibericus
Astragalus alpinus
Comandra livida
Corydalis sempervirens
Descurainia sophioides
Epilobium adenocaulon
Eq_uisetum arvense
E. scirpoides
Erigeron acris var. asteroides
Galium boreale
Gentiana propinq_ua
Hedysarum alpinum ssp. ameri-
canum
Lupinus arcticus
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 37
Mertensia paniculata
Oxytropis campestris var. varians
Pedicularis labradorica
Primula cuneifolia ssp. saxifrag-
ifolia
Pyrola asarifolia_var: incarnata
Silene williamsii
Solidago oreophila
Stellaria longipes
Tojieldia coccinea
Trientalis europaea ssp. arctica
During the first 10 years no noteworthy changes were observed in the
forb cover other than a gradual increase in the number of species
represented and in density of cover. -
Mosses are limited to a few species that become common to abundant
on recently burned areas 3 to 4 years after a fire. Oeratodon purpu-
reus is a fire species appearing 2 to 3 years after fires and spreading
rapidly. Often it attains a density of cover approaching 100 percent
on deeply burned areas where mineral soil has been exposed. Poly-
trichum commune (and to a lesser extent P. juniperinum) enter with
Oeratodon. The liverwort Marchantia polymorpha is also a fire
species, entering burned areas within the first 2 years following a fire;
locally it may attain a density of cover approaching 100 percent.
These mosses and the liverwort are the only representatives that
appear abundantly in burned areas during the first 10 years. From
an ecological viewpoint they are of interest because they develop
quicldy, forming a dense protective cover on exposed mineral soil.
Either wind or water erosion of soil thus protected seems impossible.
Lichens are rare in burned areas for the first 10 years. Occasionally
Peltigera canina var. rujescens and P. canina var. spuria are seen
after the fourth or fifth year. The fruticose reindeer lichens seem to be
completely absent.
Paper Birch Type
This type represents a relatively early stage in forest succession,
comparable to the quaking aspen type. It is of widespread occurrence
on the uplands in the interior, being especially prominent on the
Kenai Peninsula, in the Knik Arm area, in the Talkeetna Mountains,
and in the Tanana Valley. Type boundaries are usually sharp, as
would be expected in view of the fact that they generally mark the
periphery of a fire.
The forest tree composition in the paper birch type is shown in
table 3. Characteristically it is a pure type but occasionally aspen,
and rarely balsam poplar, appear in the main crown canopy. Scat-
tered white spruce, occurring in the understory, are frequently en-
countered in stands more than 80 years of age. Certain other trees,
commercially unimportant, appear in the understory. These in-
clude thinleaf alder and Sitka alder. Both of these species are most
common in mature or overmature stands. Of the willows that attain
small tree size, Bebb willow and Scouler willow may be mentioned.
Both are occasionally encountered in stands less tl;tan 80 years of age.
Initial stand density is very high; 3,000 to 6,000 (trees per acre is not
uncommon at 20 years of age. There appears to be a reasonably
good expression of dominance in paper birch with the result that
mortality is heavy in stands of small-pole size. By the time the
stands are 50 to 60 years Of age1 the number of trees has dropped to
38 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
TABLE 3.-Composition of paper birch stands in interior Alaska: Number of tree.~
and basal area per acre, by stand age, species, and diameter (brea.~t high) group
Stand age, plot number, and species
Trees Diameter 2
inches and up
Diameter 5
inches and up
DiameterlO
inches and up per' acre
1 inch 1---,---1---,,---11---,---
and up
in diam-
eter
Trees
per
acre
Basal
area
Trees
per
acre
Basal
area
Trees
per
acre
Basal
area
------------------------------------
20-year-old stand, P51-4:
~~~:is~~~~~-~~~~~~~:::::·:::::::::::::::
Mountain hemlork .... ________________ _
Thinleaf alder ... ______________________ _
Bebb willow ____ --------------________ _
25-year-old stand, P5l-6: Alaska paper birch ____________________ _
White spruce __________________________ _
Bebb wlllow ---------------------------
40-year-old stand, P5l-37:
Alaska paper birch. ____________ , ______ _
Sitka alder ____________________________ _
55-year-old stand, P5I-30: Alaska paper birch ____________________ _
Sitka alder_----------------------------
80-year-old stands:
P51-22: Alaska paper birch ____________________ _
Scouler willow_. ____________________ _
Bebb willow __________________________ _
Sitka alder ____________________________ _
P49--21: Kenai paper birch ___________________ _
Quaking aspen ________________________ _
White spruce ________________________ _
P49--22: Kenai paper birch ... ________________ _
Scouler willow_._---------____________ _
P49--23: Kenai paper birch ___________________ _
Quaking aspen ________________________ _
Scou!er willow_-----------------------·
P49-20:
Kenai paper birch .... _______________ _
Quaking asren ________________________ _
White spruce ________________________ _
Scouler willow _______________________ _
90-year-old stand, P50-12, Alaska paper birch _______________________________ .. ___ _
110-year-old stands:
P51-35: Alaska paper birch ____________________ _
White spruce __________________________ _
P51-38: Alaska paper birch. ___________________ _
White spruce __________________________ _
Sitka alder ____________________________ _
120-year-old stands:
P51-39: Alaska paper birch ____________________ _
White spruce .... ______________________ _
Greenes mountain-ash-----------------
Sitka alder. __________ ------------------
P51-40: Alaska paper birch ____________________ _
White spruce __________________________ _
P51-41:
Alaska paper birch _______ ·-------------White spruce __________________________ _
Sitka alder ___ . ____ -"--________________ .
I Basal area not determined.
No.
2, 560
210
60
130
340
6,360
40
180
2,320
1,000
1, 090
40
430
4~0
20
580
430
100
10
600
10
400
340
10
280
290
10
10
510
330
130
280
70
330
140
25
75
530
400
90
130
50
240
No.
1, 320
110
10
30
2SO
2,140
0
60
1, 760
420
1, 090
10
430
290
10
190
430
100
10
600
10
400
340
10
280
290
10
10
510
320
120
250
60
110
125
25
15
195
320
90
120
50
0
Sq.ft.
51.1
4. 7
.2
(I)
(')
75.0
0
(')
75.4
(')
130.2
(I)
86.2
(I)
(I)
(I)
72.5
21.4
3.5
81.7
(I)
60.2
48.9
(I)
64.5
49.0
4.4
(I)
127.2
105.6
13.5
140.1
12.4
(I)
53.6
7. 4
(I)
(I)
106.7
18.9
62.1
11.6
0
No.
10
0
0
0
0
20
0
0
20
0
480
0
320
100
0
0
240
70
10
330
10
210
180
10
220
200
10
10
470
300
50
240
40
0
90
25
0
0
170
70
90
30
0
Sq.ft.
1.4
0
0
0
0
2. 7
0
0
2. 7
0
85.8
0
77.4
(I)
0
0
60.3
18.8
3.5
63.2
(I)
51.4
37.9
(I)
61.1
41.2
4.4
(I)
124.4
104.2
8.1
139.7
11.0
0
51.9
7.4
0
0
98.1
18.2
60.8
9. 9
0
No.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10
0
0
0
0
0
0
0
10
0
0
0
30
50
0
140
0
0
45
0
0
0
80
0
50
0
0
Sq.ft.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6. 6
0
0
0
0
0
0
0
5.5
0
0
0
22.7
33.2
0
105.2
0
0
38.1
0
0
0
74.7
0
50.3
0
0
around 1,000 per acre and by 80 years to about 500. After 80 years
the decrease in numbers continues, but at a less rapid rate. After
100 to 120 years, the basal area of the paper birch appears to decline
and that of white spruce increases. Defect, m the form of vertical
cracks (frost cracks) m the boles of the larger trees1 and decay,
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 39
apparently due chiefly to Fomes igniarius (Fr.) Kickx, become
increasingly noticeable after the stands attain an age of about 100
years.
Forest-canopy density decreases after the forest stand is about 100
years old; this decrease results from death of individual birches and
all aspen. Subordinate vegetation occupying strata below a height
of 6 feet usually has a density of cover amounting to 30 to 60 percent.
Application of the concept of stratification of vegetation was attempted
in the paper birch type but without notable results. Greatest density
is seen in the layer from 0 to 2 inches in height, that 2 to 12 inches in
height, and the central part of the main crown canopy of the trees.
Maximum heights in the examples of mature or overmature stands
that were examined seldom .exceeded 80 feet and more frequently
were around 70 feet. Maximum diameters were seldom over 18 to
20 inches and usually were less.
Most young paper birch stands are even aged but in the course of
their development to maturity they become more uneven aged.
Tree reproduction is scanty. The average number of birch, spruce,
and aspen seedlings encountered was 185, 120, and 60 per acre, re-
spectively. Willows also are poorly represented; the average number
of seedlings per acre of all species combined was only 315. The most
common willows are Bebb, Scouler, and Barclay.
The most abundant shrubs, other than the willows, are the follow-
ing: Cornus canadensis, Ribes triste, Rosa acicularis, Vaccinium vitis-
idaea, and Virburnum edule. These occur in the majority of stands
regardless of their age. From the standpoint of cover, Cornus
canadensis and Vaccinium vitis-idaea are noteworthy. Less abundant,
but still common, are Menziesia ferruginea, Rubus pedatus, and
Vaccinium cespitosum. These species are more characteristic of
stands older than 80 years than they are of young stands.
SHRUBs, OccASIONAL TO RARE
Empetrum nigrum
Ledum palustre ssp. decumbens
L. palustre ssp. groenlandicum
Oplopanax horridus
Ribes hudsonianum
Rubus idaeus var. strigosus
Sambucus callicarpa
Sorbus scopulina
Only one grass, Calamagrostis canadensis, is prominent in the paper
birch type. It has a high frequency, as a rule occurring on more than
80 percent of the plots. The density of cover of this species (usually
less than 10 percent) increases slightly as the stands become mature
and start to open up. Poa pratensis was the only other grass en-
countered in this forest type.
Grasslike plants, especially the sedges, are practically absent.
FoRBS, MosT ABUNDANT
Dryopteris disjuncta
Epilobium angustifolium
Equisetum pratense
Linnaea borealis var. americana
Lycopodium annotinum (especially
in stands more than 100 years
of age)
Pyrola asarifolia var. incarnata
P. secunda '
Trientalis europaea ssp. arctica
40 TECHNICAL BULLE'l'IN 113 3, U . S. DEP'.r. OF AGRICULTURE
FoRB S, CoMl\WN
A1·enaria lat enflora (in s la.nd s le ss
than 100 ~~ear s of ngr )
DryopteTis austtiaca (in s tands
more than 110 years of ag e)
Equise tum atvense
E. sciTpoicles (in s ( ands lrss than
80 ~;ears of agr)
H. s ylvaticum (in stand s more
than 110 ~~ear s of age)
FoRB s, Oc cASIONAL To R ARE
Aconitum delphin1folium.
Comanclm li ·vi da
Comllothiza ttificla
Goodyem re pens var. oph1:m·d es
il1er tensia paniculata
The most abundant mosses are Hylocomium splenclens, Pleutozium
sc htebeti, and Polyttic hum commune. It appears that H. sp lenclens
enters so m ewhat later than t h e other two speci es, fir st b ec oming
prominent after the stands have passed an age of about 30 years.
After paper birch stands have attained an age of about 100 years,
specie s s u ch as D tepanoclaclu s uncinatus, Euthynchium. pmelong11m.,
and Hypnum ctista-casttensis may b e common.
}/lossEs, Oc cAs ro AL TO R ARE
Dicmnum juscescens
D. ma,_ju s
Plagioth eci um den ticulatum
Polyttichum .iuniperinum
Hypnum ctista-casttensis
Lichens are uncommon in the paper birch type. Lynge (84) noted
t h at they are also rare in t he B etula oclomta for ests in N orway. Fruti-
cose lichens are especiall y scarce. The only li chens commonly en-
co untered are Peltigera aphtho sa var. typica and P. aphthos a va.r.
variolo sa. Rare are Claclonia cornuta f. cylinclrica, C. gmcilis var.
clilatata , C. sc abriuscu la f. subl evis, Peltigera canina var. rujescens, and
P. membmnacea. In the older stands on the K enai Peninsula and in
the Su sitna River basin , Lobaria pulmonatia is frequently seen in
large masses on trees. There are indications that the li chens (other
than the peltigeras) de crease with increasing stand age.
Paper birch, in essen tially pure stands, is a fir e type. The species
seeds in on burned areas and even-age d forests res ult. Mel ecbow (92)
reported that in burns on t h e Dwin a River in Russia, birch repro-
ductio n came in over a period of about 14 years following fires ; estab-
lishment of reproduction reached a peak about 11 to 13 years after
burning . Seedbed conditions under full stands of paper birch appear
unfavorable for germination and initial surviv al of seedlings of the
species. It als o appears that there is insufficient sunligh t for seedling
development under birch canopies. There w er e no indications that
birch will follow birch in s u cc essive generations in t he absence of fire
or other catastrophic disturbance . On the other hand, there is abun-
dant evidence that white spruce seed is capable of germinating and
that spruce seedlings c an develop, if slowly , in birch forests. Barring
disturbances su ch as fire , paper birch stands are gradually converted
into white spruce-p aper birch forests.
Fires in birch fore sts tend to perpetuate the birch and reduce the
representation of spru ce. Following fires ther e is u s ually s ome s prout-
ECOLO GICAL EFFECTS OF F OREST F I RES IN AL AS K A 41
ing of birch stumps, but the principal r eas on for the d ecline in s pruce
is the l ack of se ed of t h e s p ecie s. The propor t ion of s pruce which
b ear s eed in birch s t ands is low b ecau se mos t of th e tr ees are in the
under s tory a n d only a f ew h ave their t ops in a posi t ion t o r ecei ve direct
s un ligh t. Und er these con di t ions spru ce r egen er ation ca n come on ly
from see d blo wn in from adjacent unburned s tands.
White Spruce -Paper Birch Type
The white s pruce -p ap er birch typ e (fig. 13) r eprese n ts a s tage of
s u cc ess ion comp ar able to the whit e spruce -quaking aspen type . It
is more a d v anced in terms of success ion than either the paper birch
ty p e, the quaking as p en ty p e, or the b alsam poplar type. It occ urs
widely on the uplands , probably occ upy in g more ar ea than t h e paper
birch typ e. T y p e boundaries ar e l ess well d efin ed than in. pure birch
stands; t r an si t io n t o pure birch or pure s pruce is fr equ en tly found.
F -47736 5
F I GUR E 13.-A >~·hite s p r u ce -Alaska paper b irch stand , app roximately 110 year s
old .
42 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
In the white spruce·paper birch type these species are invariably
the dominants but the relative proportion of each varies considerably
from stand to stand (table 4). This results partly from the fact that
in some stands spruce became established at the same time the birch
seeded in, whereas in other stands the birch came in first and spruce
later developed under the tree canopy. In no instance did birch in-
vade stands that were initially pure spruce. Quaking aspen is com-
monly present as scattered individuals in young stands but is poorly
represented in forests more than about 120 to 140 years of age.
Species such as black cottonwood, balsam poplar, Bebb willow, and
Sitka alder occur as minor species, chiefly in the understory in young
stands. Initial stand densities are usually high with around 2,500
spruce and birch trees per acre at 25 years of age. Mortality, especial-
ly in the birch, is high with the result that when the stands have at-
tained an l},ge of around 100 years the number of trees has declined to
around 500 to 700 per acre.
The basal area of spruce, which tends to be lower than that of birch
in young stands, gradually increases and finally exceeds that of birch
after the stand attains an age of around 130 yeBTs. Defect due to
decay in the birch is noticeable in stands around 100 years of age and
becomes very prominent thereafter.
Forest-canopy density is high in stands up to about· 100 years
of age but thereafter it decreases. In the subordinate vegetation,
density is greatest in the ground layer, up to 2 inches in height,
where 50 to 75 percent of the surface is occupied. Density is least,
usually less than 10 percent, in the layers from 1 to 2.5 and 2.5 to 6
feet in height.
Maximum heights in the mature and overmature stands of white
spruce-paper birch seldom exceed 65 to 7 5 feet for spruce and 60 to
70 feet for birch. Maximum diameters in spruce are usually less than
13 inches and in birch 15 inches.
Young stands tend to be even aged but with the passage of time
they become uneven aged due to the entry of more spruce and the
gradual opening of the stands after 100 years. The birch is usually
essentially even aged. .
Reproduction of tree species was scanty. Only in the case of white
spruce were as many as 40 percent of the plots stocked with seedlings;
these were in stands less than 140 years old. Older stands were
practically lacking in trees less than 6 feet in height. Willows too were
scarce; Bebb willow and Scouler willow were the only ones represented.
The most abundant shrubs, other than willows, are Oornus canaden-
sis, Rosa acicularis, Vaccinium mtis-idaea, and Viburnum edule, which
are found in every stand. All these species have a very high frequency
(usually 80 percent or more) but have a relatively low density of cover
(usually less than 10 percent). Rubus pedatus occurs commonly in
stands.more than 140 years of age but is practically absent in younger
stands. It was absent from paper birch forests less than about 120
years of age. Ribes triste is also relatively common. Occasional to
rare are Arctostaphylos uva-ursi, Empetrum nigrum, Ledum palustre
ssp. decumbens, L. palustre ssp. groenlandicum, Menziesia ferruginea
(only in stands more than 140 years of age), Sorbus scopulina (only
in stands more than 140 years of age), and Spiraea beauverdiana.
ECOLOGICAL EFFECTS OF FOREST FIRES LN ALASKA 43
TABLE white birch stands in interior Alaska: 4.-Composition of spruce-paper
Number of trees and basal area per acre. by stand age, species, and diameter (breast
high) group
Trees Diameter 2 Diameter 5
I
Diameter 10
per acre inches and up inches and up inches and up
Stand age, plot number, and species 1 inch
I
and up Trees Trees indiam· Trees Basal Basal Basal
eter per area per area per area acre acre acre
------------------
24-year-old stands:
P51-2: No. No. Sq.ft. No. Sq.ft. No. Sq.ft. White spruce ___________________________ 440 270 10.0 0 0 0 0
Kenai paper birch 2,040 1, 420 64.2 60 10.6 0 0
Quaking aspen ____ ~~~:::::::::::::::::: 60 40 2.0 0 0 0 0 Balsam poplar _________________________ 10 10 .2 0 0 0 0
Bebb willow __ ----------_______________ 630 40 (') 0 0 0 0
P51-3: White spruce ___________________________ 1, 280 180 5.1 0 0 0 0
Kenai paper birch._ ._ 1, 200 600 33.7 20 5.4 0 0
Quaking aspen ________ ::::::::::::::::: 80 40 3. 7 20 (') 0 0 Balsam poplar _________________________ 20 0 0 0 0 0 0
Bebb willow---------------------------1,060 400 (') 0 0 0 0 Sitka alder _____________________________ 240 . 80 (!) 0 0 0 0
105-year-old stand, P51-7:
White spruce _________________ ----------220 220 36.2 150 32.5 0 0
Alaska paper birch .. ____________________ 500 490 98.5 390 93.0 0 0 Quaking aspen _________________________ 20 20 8.8 20 8.8 0 0
110-year-old stand, P51-36:
White spruce _________ ------------------300 300 101.9 250 99.4 50 38.9
Alaska paper birch _____________________ 180 180 34.6 150 33.0 10 5.5
Bebb willow------------------------___ 40 0 0 0 0 0 0
130-year-old stand, P 50-1: White spruce ___________________________ 860 830 115.8 350 90.0 20 12.1
Kenai paper birch __________ -----·-------300 300 29.5 90 19.5 0 0 Quaking aspen _________________________ 110 110 27.0 110 27.0 10 5.5
140-year-old stand, P50-2: White spruce ___________________________ 750 630 89.3 240 71.0 40 24.2 Kenai paper birch _____________________ 120 120 19.8 70 17.2 0 0
Quaking aspen __________ ---------------110 110 36.1 90 34.4 20 15.8
145-year-old stand. P49-18:
White spruce_~-------------------------350 350 57.6 180 47.9 10 7. 9
Kenai paper birch. _____ ----------------210 210 91.7 200 91.2 80 50.7 Quaking aspen _________________________ 10 10 4.4 10 4.4 0 0
155-year-old stands:
P49-16: White spruce ___________________________ 420 420 91.4 260 81.9 20 14.7
Kenai paper birch ______ ----------------
P49-17:
160 160 77.1 140 75.8 80 51.9
White spruce ________________ ----~------260 250 70.2 190 65.7 30 17.5 Kenai paper birch ______________________ 180 180 90.7 180 90.7 70 52.1
Black cottonwood _______________ -------10 10 6. 6 10 6. 6 10 6. 6
P49-19: White spruce ___________________________ 450 440 97.5 300 89.5 30 18.8
K~nai paper birch ______________________ 190 190 85.0 190 85.0 80 54.3 Quaking aspen _________________________ 20 20 7.0 20 7.0 0 0
190-year-old stand, P51-8: White spruce ___________________________ 210 210 67.2 190 65.4 40 23.0 Alaska paper birch _____________________ 250 220 I 66.6 140 62.0 50 38.0
' Basal area not determined.
Calamagrostis canadensis is the only important grass in white spruce-
paper birch forests. It is absent or rare in young stands but appears
in old stands when they begin to Dpen up. Grasslike plants are
practically absent.
The most abundant forbs are Comandra livida, Dryopteris disjuncta
(especially in old stands), Epilobium angustifolium, Eq_uisetum arvense
(in stands more than 140 years of age), Goodyera/repens var. ophioides,
Linnaea borealis var. americana, Listera cordata (in old stands),
Lycopodium annotinum, Pyrola asarifolia var. incarnata (especially
in forests more than 100 years of age), P. secunda, and Trientalis
europaea ssp. arctica. ·
44 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICUL'l'UREl
FoRns,
Achillea borealis
Arenaria laterijlora
Equisetum pratense
Lupinus nootkatensis
L. polyphyllus
OccASIONAL To RARE
Lycopodium clavatum var. mono-
stachyon
L. complanatum
Moneses unijlora
Streptopus amplexifolius
Mosses in the white spruce-paper birch forest are similar to those
in the paper birch type. Hylocomium splendens, Pleurozium schreberi,
and Polytrichum commune are by far the most abundant. Density
of coverage is greatest for Pleurozium schreberi, 25 percent of the forest
floor usually being occupied by this species.
MossEs,
Aulacomnium turgidum
Dicranum juscescens
D. majus
Drepanocladus uncinatus
OccASIONAL TO RARE
Pohlia nutans
Hypnum crista-castrensis
Rhytidiadel ph us triquetrus
The liverwort Ptilidium ciliare is also occasionally encountered.
Lichens are poorly represented and poorly developed in the white
spruce-paper birch type. The only species at all frequently encoun-
tered is Peltigera aphthosa var. typica.
LICHENS, OccASIONAL TO RARE
Cladonia cornuta f. cylindrica C. uncialis
C. gracilis var. dilatata Peltigera membranacea
C. scabriuscula f. adspersa Stereocaulon tomentosum
As in paper birch stands, there appears to be a decline in the lichen
population, other than species of Peltigera, as the stands increase in age.
White spruce-paper birch stands may develop immediately after
fires or they ma.y result from gradual entry of white spruce into paper
birch stands which originally were pure. The nature of the seed source
available following fires appears to determine in large measure which of
the two situations will prevail. Birch does not seem to be a very
favorable nurse crop or associate for white spruce. Like all other
forest species in the interior of Alaska, white spruce develops best
when provided with mineral seedbeds and full or nearly full sunlight.
Under birch canopies, light conditions are almost certainly below the
optimum for spruce. The result is that juvenile growth of understory
spruce is slow. As the spruce crowns gradually enter the strata
occupied by the birch, another unfavorable influence is encountered.
Crown friction is so great that the spruce is deformed, often beyond
recovery. Birch crowns appear to be especially damaging in this
respect. Young birch trees whip and sway and the branches in the
crowns of the large birches also undergo much movement even in
comparatively light winds. Although conditions are not very favor-
able for development of white spruce in birch stands, they are even less
so for birch reproduction. In the absence of fire or cutting, white
spruce-paper birch stands gradually change to relatively open,
essentially pure, white spruce stands. George Cartwright in his
Labrador Journal, published in 1792 (156), described a closely parallel
successional development involving replacement of birch by spruce
and fir.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 45
Fires tend to perpetuate the birch and reduce the proportion of
spruce, as explained for the paper birch type. Here, however, birch
is not favored as much, and spruce is not repressed as greatly. The
older, larger birch does not reproduce as well vegetatively as does
younger, smaller birch, and in most of the white spruce-paper birch
stands the spruce is more likely to have begun to bear seed.
Quaking Aspen Type
The quaking aspen type represents a stage of succession comparable
to the paper birch type. The type is very widespread on upland areas
in the interior of Alaska and is particularly common on relatively dry
slopes with south or southwest exposures, and on other excessively
drained situations. Raup (124-), while working along the Alaska
Highway, repeatedly observed aspen on warm south-facing slopes; on
these situations it appeared to him that the type tends to persist for
long periods. · Excessive drainage, although evidently favoring
quaking aspen more than white spruce or paper birch, generally leads
to poor, slowly growing, rather open stands. Boundaries of the
quaking aspen type are often very sharp, marking the peripheries of
old fires.
TABLE 5.-Composition of quaking aspen stands in interior Alaska: Number of
trees and basal area per acre, by stand age, species, and diameter (breast high)
group
Stand age, plot number, and species
20-year-old stand, P51-15, quaking aspen_.------------------
25-year-old stands:
T5Q-7:
Quaking aspen ___________________ ------------------____ _ Bebb willow _______________ c ____________________________ _
P51-25:
Quaking aspen _____________________ ---------------------Bebb willow ____________________________________________ _
Scouler willow __________________________________________ _
30-year-old stand, P5Q-22:
Quaking aspen _________ ---------------.. -----------------
Alaska paper birch _____ ·--------------------------------
White spruce _______________ ----------------------------. Balsam poplar __________________________________________ _
Bebb willow--------------------------------------------Littletree willow ___ . ___________________ : _______________ _
Scouler willow ___________________________________________ _
American green alder -----------------------------------
50-year-Oid stand. P51-1:
Quaking aspen _________________ -------------------------
White spruce __________ ----------------------------------Scouler willow __________________________________________ _
60-year-old stands:
P51-14:
Quaking aspen ____ -----------------------______________ _ Balsam poplar __________________________________________ _
· Bebb willow ____________________________________________ _
P51-27:
Quaking aspen ___ ._----------------------------________ _ Alaska paper birch .. ___________________________________ _
Balsam poplar. -----------------------------------------
Bebb willow·---------------------______________ _
I No trees reached 10 inches in diameter.
' Basal area not determined.
Trees II Diameter 2 I Diameter 5 per acre inches and up inches and up I
linch
and up
in Trees 'l'rees diam-per Basal per Basal
eter acre area acre area
--------
No. No. Sq.ft. z..ro. Sq.ft.
6.120 1, 120 27.3 0 0
3, 750 1, 750 72.9 0
1, 350 0 0 ()
3, 540 1, 380 4?.9 0 0
530 0 0 0 0
140 0 0 0 0
220 50 1.1 0 0
80 40 1.4 0 0
60 20 .4 0 0
30 0 0 0 0
290 20 (2) 0 0
380 40 (') 0 0
70 0 0 0 0
180 0 0 0 0
1,040 900 89.6 320 58.2
180 0 0 0 0
460 410 (') 0 0
2,800 2,040 85.9 60 9.4
480 1 440 32.6 60 9.4
60 i 40 (') 0 0
850 620 65. 1 270 42.2
70 60 5.8 10 1.4
20 0 0 0 0
50 30 (') 0 0
46 TECH.c~ICAL BULLETIN 113 3 , U. S . DEPT. OF AGRICU L1'URE
Tree composit ion in the quaking aspen type is illustr ated in tabl e 5.
Associated with the aspen are white spru ce, Alaska paper birch or
Kenai paper birch, and balsam poplar . Representation of t h ese
specie s is u su ally poor and b ears no discernible rel ation to site. O t h er
associates , in understory position, are Bebb willow, S couler willow,
li ttl etree willow , and American green alder . The willows are most
common in young stands, l ess than abou t 40 year s of age. Initi al
densities may b e very high, 3 ,000 to 6,00 0 stems 1 inch and l ar ger in
diameter being found per acre in stand s aro und 20 to 25 years old
(fig. 14 ). Even in stands 50 to 60 years old there are frequently 1,000
to 3,000 stems p er acre . Mortali ty of as p en is high in trees 1 to 2
inches in diameter, but new sprou ts continue to issue from the roots,
particularly in young stand s. After stands are about 60 years old,
decay becomes very common and t h ey start to open up as trees die.
Forest-canopy density appears to decrease with increasing stand
age . In the subordin ate vegetation t h e greatest density is found in
the ground l ayer (0 to 2 inches) wh er e about 35 percent of the surf ace
F-477368
Fra uRE 14.-A 20-year-old quaking a s p e n stand. The dominants are 2 to 3
inches d. b. h. and 25 to 30 fe e t tall.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 4 7
is occupied. Density is least in the layers 1 to 2.5 feet and 2.5 to 6
feet above the ground level. Vegetation density in these layers is
usually less than 10 percent.
Maximum heights in the oldest stands classified as pure aspen
seldom exceeded 60 feet and maximum diameters were usually less
than 10 inches. These values do not represent the maximum sizes
attained by aspen in the interior of Alaska . With increasing age, size
also increases (especially diameter) but the stands are then likely to
be classified as white spruce-quaking aspen.
Aspen stands are essentially even aged, but as they pass into the
white spruce-quaking aspen type they tend to become uneven aged.
Birch reproduction is almost lacking in aspen stands, and white
spruce reproduction tends to be sparse unless a good seed source is
near. Aspen reproduction averages around 1,400 individuals per
acre, but these are mostly root suckers which soon die. Of the
willows , Bebb willow is most abundant, especially in stands less than
40 years of age. Blueberry and Scouler willows are occasionally
encountered.
The most abundant shrubs, other than willows , are Arctostaphylos
uva-ursi (present in every stand), Ro sa acicularis, Shephenlia canc-
densis, and Vaccinium viti -idaea.
SHRUBS, OccASIONAL '.ro RARE
Arctostaphylos alpina ssp. rubm
B etula glandulosa
Cornus canadensis
Empetrum nigrum
L edum palustre ssp. gro en landicum
Rubus idaeus var. strigosus
Vaccinium cespitosum
V. uliginosum
Viburnum edule
A wider variety of grasses is encountered in aspen stands than in the
paper birch or white spruce-paper birch forests . Presumably this
results from the more open canopies in most aspen communities. The
most prominent grasses are Agrostis sca bra, Calamagrostis canadensis,
and Festuca altaica. Of these the last two have the highest density,
often 10 to 50 percent. Other occasional to rare species, which appear
in relatively mature stands, are Bromus pumpellianus, Calamagrostis
purpurascens, and Poa glauca.
Grasslike plants are very rare in aspen stands . Occasionally species
such as Carex concinna and 0. supina ssp. spaniocarpa are seen.
Forb species represented are listed below.
FoRBs , :MosT ABUNDANT
Achillea bor ea lis
Epilobium angustifolium
Equisetum scirpoides
Lupinus aTCticu s
Pyrola secunda
349169-56--4
Linnaea bor ealis var. americana
Mertensia paniculata
FORBS , COMMON
Zigaden us elegans
48 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
FoRBs, OccASIONAL TO RARE
Arenaria laterijlora
Aster sibericus
Bupleurum americanum
Comandra livida
Equisetum pratense
Galium boreale
Geranium erianthum
Lycopodium annotinum
L. clavatum var. monostachyon
L. complanatum
Pedicularis sudetica
Polemonium boreale
Pyrola asarifolia var. incarnata
Saxifraga tricuspidata
Solidago multiradiata
Mosses do not attain the density of cover in aspen stands that they
do in paper birch and white spruce forests. Density of cover in a
given species seldom exceeds 5 percent. No species were found
abundant.
MossEs, OccASIONAL To RARE
Aulacomnium turgidum Hylocomium splendens
Bryum cuspidatum Polytrichum commune
Camptothecium lutescens P. juniperinum
Campylium stellatum P. strictum
Drepanocladus uncinatus
A liverwort, Ptilidium ciliare, is occasionally seen.
The lichen population in aspen stands is considerably greater than
in paper birch or white spruce-paper birch; perhaps this is because
aspen forests are more open. The lichen cover appears to decrease
slightly after the stands attain an age of about 30 years. No single
lichen species is especially abundant or characteristic.
Cetraria cucullata
C. nivalis
Cladonia alpestris
LicHENs, OccAsiONAL TO RARE
C. lepidota
C. cariosa f. cribrosa]
C. cenotea f. crossota
C. chlorophaea f. simplex
C. coccifera
C. coniocraea f. stenoscypha
C. cornuta f. cylindrica
C. degenerans f. euphorea
C. jurcata var. racemosa
C. gracilis var. dilatata
C. gracilis var. elongata f. laontera
C. multiformis f. simulata
C. multiformis f. subascypha
C. squamosa f. muricella
C. uncialis
Nephroma arcticum
N. expallidum
Peltigera aphthosa var·. typica
P. canina var. rujescens
P. malacea
Stereocaulon paschale
S. paschale var. grande f. velutinum
S. tomentosum
Aspen stands develop following fires. Regeneration is from seed-
lings and root suckers, with few, if any, stump sprouts. Abundant
vegetative reproduction from root suckers almost invariably follows
on burned areas formerly supporting aspen. In areas where aspen was
absent or scarce in the previous stand, reproduction, if any, is of seed
origin. Aspen seeds are borne in large numbers and are easily dis-
seminated, but fairly close proximity to a seed source seems essential
for the establishment of seedlings in quantity. Even-aged stands are
characteristic. ·
:EC6LOGICAL EFFECTS 6F' FO:El.EST FI:El.ES IN ALASKA 49
In the absence of fire or other comparable disturbance, aspen does
not follow aspen; a possible exception may be found on excessively
dry slopes having a southerly or westerly exposure. On such sites,
Stoeckeler (147) regards aspen as the climax. White spruce, which
may have started with the aspen immediately after a fire or which
more usually entered the stand later, gradually dominates the site.
Aspen is an intolerant, short-lived species as compared with white
spruce, which is relatively long .lived and tolerant. w·hite spruce is
evidently subjected to less suppression and less deformation of crowns
in aspen than in paper birch forests.
Fires in aspen stands perpetuate aspen and destroy practically all
the white spruce that may have entered the stands. Spruce is greatly
handicapped in surviving fires because the living branches are close
to the ground, the bark is thin, and the species is strictly dependent
on seedling reproduction. In the Lake States, Stoeckeler (148) found
that repeat burns in established aspen stands reduce site index from
6 to 25 feet.
White Spruce-Quaking Aspen Type
This type represents a stage of successional development directly
analogous to the white spruce-paper birch type. It is widely repre-
sented on the uplands in the interior, perhaps being most common on
relatively dry slopes having a south or southwest exposure and on
excessively drained outwash or delta soils. On the drier situations,
entry of white spruce into aspen stands is slower, and subsequent de-
velopment is less rapid than on sites with favorable moisture relations.
In the white spruce and quaking aspen type these species are the
dominants, but the relative proportion of the two species varies sub-
stantially from stand to stand (table 6). This usually is due to com-
position of the reproduction at the time the stand was established and
to the rate of subsequent invasion of spruce. On sites of average or
better than average quality, white spruce frequently comes in at the
same time the aspen is established, that is, shortly after a fire.
With a source of seed available, white spruce seedlings become
established on good sites. On the poorer, dry sites, white spruce
establishment immediately after a fire is difficult, and in such situ-
ations spruce slowly reenters the area under the canopy of the aspen
(fig. 15). This process is evidently very slow on steep slopes having
a south or southwest exposure. Associated with white spruce and
quaking aspen are balsam poplar and several. willows of which Bebb
willow is usually the most important. As a group, willows are present
to the extent of about 8,700 stems per acre; about 6,400 of these are
Bebb willow. Other willows encountered are Barclay willow, in-
cluding var. hebecarpa, blueberry willow, and Scouler willow. Initial
stand densities are high, with 1,000 to 2,000 white spruce and quaking
aspen stems per acre at 20 years. By the time the stands have at-
tained an age of about 100 years, the number pf stems per acre has
declined to around 400 to 600. White sprue~ gains in importance
with increase in stand age whereas the importance of aspen declines
(fig. 16). In one white spruce-quaking aspen stand 115 years old,
there were 210 living and 690 dead aspen trees per acre in diameter
classes above 3 inches. In this same stand there was essentially no
mortality in white spruce, and the trees appeared thrifty.
50 TECHNICAL BU LLET IN 113 3, U . S . DEPT. OF AGRICU LTURE
T A BLE 6.-Comp!lsiti m of white spruce-qu aking asp en starnds i n inter ior Alaska:
Numb er of tree s arnd ba sal are a p er acr e, by stand ag e, species, and diameter
(bre ast high) group
Trees Diameter 2
I
Diameter 5
I
Diameter 10
per acre inches a nd up inches a nd up inches and up
Stand age, plot numoer, and species 1 inch I a nd up rrrees rrrees
I
Trees in di am-Basal Basa l
I
B asal
eter per area per area per area f. ere acr e acre
------------
20 -year -old s tand s :
N o. N o. Sq . ft . N o. ."q.}t. No . Sq.ft. P49-24 :
White s pruce. ____________ --------------260 170 6. 9 0 0 0 0
Qua king asp en ____ ----------___________ 2, 040 850 18.1 0 0 0 0
B eh b willow __________ -----------------20 0 0 0 0 0 0
P 49-25:
White s pru ce. _________ ---------------250 140 8.1 20 2. 7
Quakiny, aspen ___ -----------___________ 870 490 18.0 0 0 Bebb w illow ___________________________ 700 0 0 0 0
P 49-26:
Whi te s pruce. _______________ ----------5i0 410 34. 5 120 19.5
Quaking asp en _______________________ --I , 610 710 20. 7 0 0
B lack cottonwood ... -------------------40 10 .5 0 0
P 49-27:
White spru ce ____________ --------------760 550 47.5 130 25.4 0 0
Qua king aspen ___________________ ------170 90 2. 8 0 0 0 0
B alsam po pla r ___________ -----___ ----· 70 40 1.7 0 0 0 0
60-year -old stan d. P 51-13:
200 140 10.6 40 7. 3 0 0 Whi te spruee _______________ ------------
Qua k ing aspen _________________________ 450 450 96 .4 360 90 .0 10 5. 5
B alsam p oplar ------------------------· 10 10 3. 5 10 3. 5 0 0
B ebb w illow ___ ------------------------410 150 (I) 0 0 0 0
6&-year-old stand, P 50-4 :
59.1 0 0 White spruee _________ . -----------------990 820 87.2 290 Qua k in g as pen _________________________ 370 360 59.4 190 49.6 0 0
B alsam pop lar. ________________________ 10 10 2. 7 10 2. 7 10 2. 7 B ebb w illow ___________________________ 270 270 (I) 270 (I) 0 0
90-year-old stan d, P 50-I 3:
White spruce ______________ -------------190 190 40.0 110 3-1.5 10 10.9
Qua king asp en . __________ --------------390 380 106.3 300 100.4 60 36.2
B a lsam p opla r. .. ----------------------130 120 25.0 80 21.9 10 11.0
B e bb w illow ___________________________ 90 10 (') 0 0 0 0
11 5-y ear-old s t and , P50-6: Whi t e s pruce ___________________________ 130 130 30.1 100 27. 9 10 11.0 Quaking asp en _________________________ 230 210 81.0 180 78.8 60 38. 7 B a lsam poplar. ________________________ 210 80 1.7 0 0 0 0
I B asal a rea not d e t ermined .
Forest-canopy density tends to be low in stands of this t y pe, espe-
cially when the aspen begins to drop out after about 100 years. In the
subordinate v egetation, d ensity is greater in stands less than 60 years
old than in older for ests . The ground lay er (0 to 2 inches in height)
has the highest density, and the layers 1 to 2.5 feet and 2.5 to 6.0 feet
in height have the lowest d ensity.
Maximum heights in. the mature and overmature stands of white
spruce-quaking aspen seldom exceeded 60 to 70 feet for spruce and 65
to 75 for quaking aspen . :Maximum diameters in spruce and aspen
were seldom more than 10 to 12 inches.
White spruce is uneven aged in most stands whereas the aspen is
essentially even aged . The spread of ages in spruce increases with in-
crease in stand age .
Spruce reproduction is present in all stands, but the number of trees
per acre is low, ranging from 200 to 6,800 per acre and averaging 1,100.
Aspen root sucker s averaged about 1,600 shoots per acre. These
shoots appear, live a few years, and then die. Birch reproduction is
very scanty and balsam poplar is only occasionally encountered. It
is obvious that, of these four species, white spruce is the only one
capable of surviving and developing under ·the forest canopy.
ECOLOGICAL EFFECTS OF FOREST FIRES rcN ALASKA 51
F -477367
FIGURE 15.-A 65-year-old quaking a s pen stand with an under story of black
spruce and white spruce. The dominant quaking aspen trees are 4 to 9 inches
d. b. h. and 45 to 50 feet tall. The spruce trees in the understory are 2 to 4
inches d. b. h . and 25 to 30 feet tall. Arrows point to aspen barked by moose.
Kenai Penins ula, 1950.
MosT ABuNDAN'r SHRUBs, OTHER THAN THE WILLows
Arctostaphylos uva-ursi
Cornus canadensis
Rosa acicularis
Shepherdia canadensis
Vaccinium vitis.~idaea ..
SHRUBs, OccASIONAL TO RARE
Arctostaphylos alpina ssp. rubra L. palustre ssp. gro enlancl?'cum
Betula glandulosa Potent?:lla fruticosa
Empetrum nigrum Vaccinium cespito sum
Ledum palustre ssp. decumbens Viburnum edule
The most prominent grass is Calamagrostis canadensis, which occurs
most commonly in the young stands. Agrostis scabra and F es tuca
altaica occm r arely. Grasslike plants are even more scarce than the
grasses; Carex concinna was about the only species enco unter ed .
FoRBs, :MosT ABUNDANT
Epilob ium angustijolium Pyrola secunda
Linnaea boreal?s var. americana '
Equisetum scirpoides
Lupinus nootkatens1:s
Moneses uniflora
FoRBs, CoMMON
Pyrola asarifolia var. incarnata
T1 ·ientalis europaea ssp . arctica
52 TECHNICAL BULLETIN 11 3 3, U . S . DEPT. OF AGRICULTURE
F-477369
FrG U RB 16.-A quaking a s p e n-\Yhi te s pruce stand in which t ho dominant quaking
aspen t r ees are approximate ly 115 years of age, 8 to 12 in ches d . b. h ., a nd 60
feet tall . The white s pruce t r ee are 5 to 11 inches d . b . h. and 40 to 50 feet
tall. :\Iuch of t h e quaking a s p e n is d ead or d ecad e nt.
FoRBs, O ccASIONAL TO R ARE
Achillea bor ealis
Aconitum delphinifoli um
Anna1·ia laterijlora
Ca stilleja pall ida ss p . m exi ae
Comandra lim.da
Dryopteris disjuncta
Eguise tum pratense
E. sylvaticum
Galium bor eale
Hab enari a obtusata
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 53
Lupinus arcticus
Lycopodium annotinum
lvlertensia paniculata
P edicularis labradorica
Pyrola viren s
Sanguisorba stipulata
S enecio integerrimus
Stellaria longipes
Fiola renifolia var. brainerclii
1v1osses are more prominent in the white spruce-quaking aspen type
than in the pure asp en forest. The most abundant species are
Drepanocladus uncinatus , Hylocomium splendens, and Polytrichum
commune. P. commune is most prominent in young stands whereas
H . splendens is most abundant in old stands.
:MossEs, OccASIONAL To R ARE
Ceratodon purpureus
Climacium dendroides
Dicranum clrummonrl ii
D. fragilifolium
D. fusc escens
Ditrichum jlexicaule
Eurhynchium praelongum
Pleuro zium schreberi
Pohlia nutans
Polytrichum strictum
Tom enthypnum nitens
Of the lichens , Peltigera aphthosa var. typica and P. aphthosa var.
variolosa are most abundant. In some y oung stands less than 25
years of age, Cladonia cenotea f. crossota and C. crispata var. injundi-
bul1fera are common.
LICHE NS, OccASIONAL TO RARE
Cetraria islandica
Cladonia cornuta f. cylindrica
C. crispata var. virgata
C. gracilis var. chordalis f. leuco-
chlorea
C. gracilis var. dilatata
C. gracilis var. elongata f. laontera
C. mitis
C. pyxiclata var. pocillum
C. sylva tica
Stereocaufon tom entosum
White spruce-quaking aspen communities may become established
immediately following fir es but more c haracteristically they arise as a
result of succession with the spruce gradually invading essentially pure
aspen communities. Spruce seeds can germinate and the seedlings
can survive and develop slowly under the aspen crowns. In the
absence of fire or other devastating disturbance, spruce gradually
replaces aspen and r elatively open spruce stands are the end result.
Garman (47) stated that in central British Columbia the elimination of
aspen from mixed stands becomes rapid after an age of 60 years is
reached. Millar (97) reported that in the "clay belt" "in Ontario
growth in aspen stands is balanced by mortality at about 100 years of
age Mel from then on the aspen begins to disappear. The spruce, on
the other hand, continues to grow. 1
Fires in the type are far more destructive of ' spruce than of aspen.
The reasons for the selectivity of fire have already been m entioned for
other types. They include principally such characteristics as thin
bark, flammable foliage carried well down toward the ground, and
imtbility of spruce to reproduce b y sprouting. The rapid height
54 TECHNI CAL BULLETIN 11 3 3, U. S . DEPT. OF AGRICULTURE
growth and early seed production of aspen root suckers gives it an
advantage over spruce in recovery from fir es. Severe fires in the
white spruce-quaking as pen type usually lead to pure aspen stands with
most of t,he r egeneration of root sucker origin .
Balsam Poplar Type
Balsam poplar in essentially pure stands is a forest type character-
istic of recently d eposited alluvium and is found along most of the
l arger rivers in the interior of Alaska. Many stands represent the first
forest stage in a primary successional series. For reasons that are not
apparent, balsam poplar is especiall y well adapted for reproduction on
a lluvial bars. These are a common feature a long most of the Alaskan
rivers that are fed by the melt water from glaci ers . Asp en , whi ch
might be ex pected in these habitats, is a rare species. Occasionally
b alsam poplar spread s from its characteristic stream vall ey habitat to
adjacent upland sites that have been swept b y fir es.
Forest composition in this t y p e is indicated by the few sampl es
presen ted in table 7. Balsam poplar stands are often pure but in
many of them white spruce b eco mes an important el ement, especially
in old stands (fig . 17 ). Alaska paper birch is a l ess important and less
common associate . Small understory species such as Sitka alder,
American green alder, thinleaf alder, littl etree willow, f eltleaf wi llo w,
and Scoul er willo w are oc casionally encountered. Initial densities
are commonly high, with as m an y as 3,500 trees per acre at 25 years
of age. D ensity tends to remain high even in mature fore sts . D ecay
appears co mmon in old stands.
Maximum h eights of balsam poplar in the stands studied did not
exceed about 70 fe et, and maximum diameters about 36 inches.
However , substantially larger trees occurred in some of the better
stands in the Susitna basin. Thomas (153) s t a t ed that in his journey
T ABLE 7.-Composition of balsam poplar stand s i,n i nterior Alaska: Number of
tr ees and ba sa L mea per acre, by st and ag e, species, and diamete1· (bre a.s t high )
group
Trees Diameter 2 Diameter 5 Diameter 10
per acr e in ches a nd u p inches and up inches and up
Stand age, plot number, and species 1 inch
a nd up
in diam-Trees Basal Trees Basal T r ees Basal
eter per are a per are a per ar ea acre acre ac re
------------
No. No . Sq .ft. No. Sq.f t . No . Sq.ft.
25-year·old stand, P51-10, balsam poplar ... 3, 480 360 8. 5 0 0 0 0
100-year -o ld stand, P50-17: Balsam poplar_ .. __________ . _________ .. 690 69 0 162.9 560 152. 3 20 10.9
White spruce ____ ----------------_______ 70 70 21.4 60 20.6 20 12.1
Sitka alder. .. ________ ---------... -----· 50 50 (1 ) 0 0 0 0
Ameri can green alder_ __________________ 30 0 0 0 0 0 0
Littletree willow----------------·------40 10 (1) 0 0 0 0
Feltleaf willow ________ ------------_____ 120 20 (') 0 0 0 0
150-year-old stand;P50-20: Balsam poplar _________________________ 510 510 171.4 500 170.5 110 74.1 Thinleaf a lde r __________________________ 320 100 (1) 0 0 0 0
Littletree w illow ____ -------------------40 40 (1) 0 0 0 0
200-year-old stand, P51-9 :
I
B a lsam popla r •. _______________________ 90 90 143.9 90 143.9 90 143.9 White spruce ___________________________ 250 250 84.0 200 81.8 80 56.1 Alask a paper b irch _____________________ 120 120 24.8 60 22.4 30 16.4
Sco uler w illow __ -----------------------10 10 (1) 10 (1) 0 0
I B asal area not d etermined.
ECOLOGICAL EFFECTS OF F ORES'r FIRES IN ALASKA 55
F -477370
FIGURE 17.-A bals am poplar-white spruce stand. The oldes t poplars are 200
years of age and are nea rly 30 inches d. b. h . and 75 feet tall. The oldest white
s pruce are 105 year s of age, 13 inches d . b. h., a ud 70 feet tall. On Matanuska
River, near Palme r, 1951.
along the Susitna River h e occasionally saw cottonwood trees from
3 to 6 f ee t in diameter. Balsam poplar stands are often even aged
but ma_v also exhibit a considerable range in age.
R eproduction within a stand is generally s parse with only oc casional
white spru ce, balsam poplar, and rarely paper birch seedlings.
SHRUBs, OccASIONAL TO R AH.E
Alnus crispa
Cornus canadensis
Elaeagnus commutata
L edum palustre ssp. gro enlanclicum
Potentilla jrutico sa
Rosa ac i cularis
Salix arbusculoicles
S. setche llian(L
Shephe1·clia oanaclensis
Vi burnum eclule
Grasses appear to b e rare, the only one encountered being Calama-
grostis pu1·purasc ens. Grasslike plants are practically absent. Of the
£orbs , Epilobium angustifolium is p erhaps the most abundant . Actu-
ally no species seems to b e outstanding.
56 TECHNICAL BULLETIN 11 3 3, . S . DE P T. OF AGRICULTURE
FoRBS,
Aquilegia bre vis tyla
O ccAS IO NAL •ro R ARE
ATtemisia aTctica
Comanclra livicla
Equisetum w ·vense
Goocly em Tepens var . ophi oicl es
H.abena1 ·ia obtusata
H.ecl y saTum alpinum ssp. amel'?·-
·eanufm.·-: , ,
H. mackeni i?·
11{ertensia paniculata
(Jxytropi s cam pes tris var. varians
Pyrola asarijolia var. incaTnata
P. se cuncla
lVIo sses are not prominent in balsam poplar stands. Seldom do es a
s p ec ies have a coverage of more t han 5 percent .
N iossEs, O ccAsiO NAL TO R ARE
Bryum caespiticium D repa11oc la clus U11C?·natu s
Oe ratoclon pur pureus H.yp num re vo lutum
D ic ranum clTummonclii H.ylo comium s pl enclens
D . .fragilijolium Pleuro zium sc h1·ebe1·i
D itrichum jl exic aule
Lichens are ver y poorly represented. Only occasionally are t he
fo llo wing speci es encountered: P eltigera canina var . 1'ufescens, Stereo -
caulon paschale var. alpinum , and S. paschale var. alpinum f . gracil en-
tum. As t h e stand s mat ure a nd as white spruce d evelops, P elti gera
ap htho sa var. typica and P. membmnacea appear.
The successional posit ion of t h e balsam poplar type is not entirel y
cl ear . Characteristically i t d evelop s on recently d eposi ted bars
along rivers but the p ermanen ce of t h e type is not known. On some
areas white spruce is gradually a ttaining dominance and will even-
t ually replace the balsam poplar. In other situations t h e poplar
a ppears t o b e a self-p erp etuating co mmun i ty without any clear t r end
t oward r eplacem ent b y s pruce or other species. P erhaps balsam
poplar may occupy flood plain areas indefinit ely if they are subj ecte d
to periodic overflow with d eposition of alluvium. Raup (1 25)
r egarded willows and alders as pred ecessors of balsam poplars on flood
plains in t h e southwestern Mack enzie r egion. Pulling (1 23) viewed
t h e roo t system of balsam poplar as more or l ess fl exible but not
adapted t o soils a s shallow as some of those in which white spruce can
thrive .
Fires occur in th e balsam poplar type but are no t nearly as common
as in o t h er forest communities . Based on limited eviden ce, it ma)-
b e said that following fir es the type r egen er ates b y m eans of root
s u ck er s, a nd, t o a l esser exten t, from seed . In his r es p ect t h e s p ecies
b ehaves in much t h e sam e way as aspen.
White Sprztce Type
The white spruce typ e is the climax forest community on upl and
areas in the interior of Ala ska (fi g . 18 ). It is widespread and is respon-
sible, more than any other fore s t. type , for the vegetational aspect of
t h e l a ndscap e . The dark, almost black , forest m a ntle s o charac teris ti c
of upland areas in t h e in terior is white s pruce . Only in reg ion s t hat
have esc aped r ece nt fir es is the cover of s pruce forest complete; com-
monly it is broken b y more or less exten sive areas of paper birch , as pen,
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 57
F-477359
FIGURE 18.-Ciimax white pruce forest along t h e Nelchin a River, m a rked b y
eroding bluffs. Along G lenn Highway, at mi le 143, lo ok in g eastward. 195 1.
or types transitional between t hes e and pure s pr u ce . Boundaries are
u s ually very sh arp , m arkin g the edges of fire s . These boundaries be-
tween white spruce for est and as pen or p ap er birch forest are a co m-
mon feature and appear as distinct lines t hat m ay b e seen for miles .
Generally the white s pruce type is pure with only occasional rep-
r esentatives of black s pruce, paper bir ch , and b al sam poplar (tabl e
8). The under stor y of small trees or l a rge s hrubs includes sever a l
s p ecies of will ows and alder. B ebb willow i s t h e most abundant
m emb er of t h e group, with 2 ,000 to 3,000 stem s 1 inch in diam eter ,
or l arger, p er acre in yo ung stands, t h at is, up to 20 to 30 years
old. With incr ease in stand age, the number of stem s of B ebb will ow
decreases 1.mtil t h ey b eco m e very s parse in stands older than 160
year s. O t h er will ows attaining diameters of 1 inch , or more, at
breast h eight include li ttl etree willow , feltl eaf willo w, Sco uler willow,
and Salix glauca var . aliceae. Like the B ebb willow , these s p ecies ar e
most ab undant in y oung stand s and d ec r ease in numbers rapidly with
incr easing stan d age , becoming scarce in stands older t han about 160
year s . The principal alder is Si t k a alder ; American gr ee n alder oc-
curs occasionall y. Unlik e t h e willow s, t he alder is most common in
t h e older stands, b ein g scar ce in for ests h aving an age of l ess than abou t
120 yeai's. t
Initial densities are commonly high , with 2:000 to 3,000 stem s 1
inch and l arger in diameter per acre in stands from 20 to 25 years of
age . fhe total number of stem s per acre de cr eases wi t h in cr easing
age , but even at 160 to 180 years there are usually 300 to 500 p er acre.
In stands around 160 to 18 0 year s of age, 100 to 150 trees p er acre
h ave diameters of 10 inch es or more.
BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
of ·white spruce stands in interior Alaska: Number of
per acre, by stand age, species, and diameter (breast high)
'stru:id age, plot numher, and species
20;year-old stand, P51-17:
White spruOO------------------· --
Bebb willOWc-----------------------.... Littletree willow __________________ ----
Brili:c glauca var. aliceae. _______________ _
35-year-old stand, P51-20: White spruce ____ . _____________ ----------
Bebb willow_--------------------------
Littletree willow.-----·----------------
40-year-old stand, P5Q-24:
White spruce ______________ ------------
Bebb willoW---------------------------
Littletree willow.----------------------
55-year-old stand, P5Q-14:.
White spruce---------------------------
Bebb .willow_---------______ -----------
75-year-old stand, P51-18:
White spruce ________ , ____ --------------
Bebb willOW---------------------------
105-year-old stand, P51-31, white spruce __ _
120-year-old stands: P5Q-10, white spruce ____________________ _
P5Q-18:
White spruce--------__ -___ -------------.Balsam poplar _____________________ ,_
125-~~l~p=~:-~~~~~-----------------
Black spruce.------------. _______ ------Alaska paper birch ____________________ _
American green alder .. ________________ _
130-year-old stand, P51-12: White spruce _____________ --------------
Bebb willow.--------------------------
Littletree willow -•---------------------
135-year-old stand, P51-33, white spruce ___ _
140-year-old stand, P51-34, white spruce __ _
15o-year-old stands:
P51-16:
White spruce.---------_______ ---------.
Bebb willoW---------------------------Srili:c glauca vat. aliceae ________________ _
Littletree willow-----------------------
P5I-26: White spruce _________________________ __
Alaska paper birch ____________________ _
Black spruce __________________________ _
Sitka alder _______________ . __ ._. _____ ...
Bebb willOW---------------------------
160-year-old stand, P51-19: White spruce __________________________ _
·Black spruce __________________________ _
Bebb willow __________________________ _
Littletree willow ______________________ _
Srili:! glauca var. aliceae ________________ _
165-year-old stand, P5Q-3:
White spruce ______________ -------------
Kenai paper birch _____________________ _
170-year-old stands:
P4!Hl: White spruce __________________________ _
Kenai paper birch _____________________ _
P5o-23: White spruce __________________________ _
Balsam poplar __ ------------------------Feltleaf willow----------__________ : ___ _
Little tree willow-----------------------
175-year-old stand, P49-2: White spruce __________________________ _
Kenai paper birch .. ·---------------____ _
Diameter 2 Diameter 5 Diameter 10
Trees inches and up inches aud up inches and up
Pf~c~e 1------~-----1------------:-------------
and up
indiam~
eter
No. a;oBo
2. 980
120
560
950
1,390
20
830
450
230
I, 620
490
3,040
20
2,210
920
I, 090
20
220
190
30
60
280
330
!50
I, 530
200
200
180
I, 240
90
385
55
15
llO
10
340
880
100
90
90
520
80
230
50
390
30
90
10
290
40
Trees
per
acre
No.
120
0
0
0
780
190
0
570
0
0
1,240
180
2,400
20
2,150
850
I, 030
20
220
190
30
10
250
100
30
1,410
200
160
0
0
20
335
25
15
15
0
330
360
0
10
0
510
80
230
50
360
30
0
0
290
40
Basal
area
Sq.ft.
2.6
0
0
0
88.fi
(')
0
75.3
0
0
94.1
(')
170.7
(')
224.9
140.4
353.2
8.9
79.5
38.4
II. 5
(')
171.7
(')
(')
183.9
85.3
98.6
0
0
(')
ll9. 7
1.8
5. 7
(')
0
69.0
47.4 o·
(')
0
159.0
22.2
192.4
34.9
121.2
6.3
0
0
195.3
25.4
Trees
per
acre
No.
0
0
0
0
360
0
0
240
0
0
220
0
400
0
I, 030
430
730
20
160
!50
30
0
250
10
0
610
175
!10
0
0
0
255
5
15
0
0
210
200
0
0
0
350
80
230
50
270
20
0
0
270
40
Basal
area
Sq.ft.
0
0
0
0
61.0
-0
0
62.7
0
0
48.8
0
73.6
0
165.3
ll8.6
337.4
8.9
76.4
35.7
II. 5
0
171.7
(')
0
141.0
83.5
97.3
0
0
0
ll6. 5
. 7
5. 7
0
0
62.2
39.3
0
0
0
147.0
22.2
192.4
34.9
ll4.5
5.5
0
0
193.9
25.4
Trees
per
acre
No.
0
0
0
0
0
0
0
30
0
0
20
0
0
0
0
30
300
10
70
0
0
0
130
0
0
40
65
60
0
0
0
90
0
0
0
0
30
0
0
0
0
130
0
170
50
60
0
Q
0
210
30
Basal
area
Sq.ft.
0
0
0
0
0
0
0
17.5
0
0
10:9
0
0
0
0
16.4
220.8
5.5
50.1
0
0
0
131.8
0
0
23.0
52.6
79.7
0
0
0
68.2
0
0
0
0
18.8
0
0
0
0
18.1
0
171.0
34.9
50.4
0
0 • 0
177.1
22.7
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 59
TABLE B.-Composition of white spruce stands in interior Alaska: Number of
trees and basal area per acre, by stand age, species, and diameter (breagt high)
group---<Jontinued
Trees Diameter 2 Diameter 5 Diameter 10
per acre inches and up inches and up inches and up
Stand age, plot number, and species 1 inch
and up Trees indiam-Trees Basal Trees Basal Basal
eter per area per area per area acre acre acre
------------------
180-year-old stands:
P49-10: No. No. Sq. ft. No. Sq. ft. No. Sq.ft.
White spruce _____ ------·----___________ 440 420 165.4 300 159.9 150 113.7
Kenai paper birch ______________________ 40 40 21.0 40 21.0 20 16.1
Sitka alder·-------------------_________ 500 170 (1) 0 • 0 0 0
Scouler willow-------------------------20 20 {I} 0 0 0 0
Quaking aspen _______ ----------·--_____ 10 10 .2 0 0 0 0
P50-16, white spruce _____________________ 570 550 183.5 360 174.9 180 126.1
185· year-old stands:
P49-1:
White spruce -------------------_______ 290 290 166.7 270 165.3 140 120.0
Kenai paper-birch ______________________ 50 50 23.9 50 23.9 30 17.5
Black cot~onwood ______________________ 20 20 28.4 20 28.4 20 28.4
P49-4:
White spruce ______________ -------------260 260 162.3 240 161.0 140 .129. 5
Kenai paper birch .. ____________________ 20 20 12.3 20 12.3 10 7.9
P49-9:
White spruce .... __ ---------------------520 510 194.5 400 188.4 170 120.5
Kenai paper birch ______________________ 40 40 16.0 40 16.0 20 12.1
190-year-old stands:
P49-ll: White spruce ___________________________ 680 670 202.6 460 192.6 140 100.9
Kenai paper birch .. -------------------40 40 19.0 40 19.0 20 12.1
Sitka alder-----------------------------30 10 (1) 0 0 0 0
P49-12: White spruce ___________________________ 210 210 134.1 180 132.2 120 116.3
Kenai paper bircJL _____________________ 40 40 43.6 40 43.6 40 43.6
Sitka alder __ : ___________ ---------------50 40 {1) 0 0 0 0
200-year-old stands:
P51-11:
White spruce ..... ----------------------54 42 14.4 30 13.8 12 8.9
Black spruce ___________________________ 42 18 . 5 0 0 0 0
P51-24, white spruce _____________________ 860 840 202.5 640 191.6 70 41.8
215-year-old stands:
P49-5, white spruce----------------------240 240 192.6 200 190.5 170 . 181.7
P49-14: White spruce ___________________________ 300 300 175.7 240 172.0 140 140.6
Kenai paper birch ______________________ 10 10 14.0 10 14.0 10 14.0
Sitka alder---------------------------·_ 380 250 (1) 0 0 0 0
220-year-old stands:
P49-7: White spruce ... ________________________ 240 240 171.2 240 171.2 200 156.2
Kenai paper birch ______________________ 30 30 10.6 10 9.2 10 9.2
P50-9: White spruce ___________________________ 770 730 64.4 180 33.9 0 0
American green alder ___________________ 1,190 80 (1) 0 0 0 0
225-year-old stand, P49-13:
White spruce.--------------------------410 410 226.0 370 223.3 180 157.5
Kenai paper birch ______________________ 10 10 4.4 10 4.4 0 0
Sitka alder-----------------------------230 l10 {I) 0 0 0 0
230-year-old stands:
P49-8: White spruce. ____ ----__________________ 190 190 125.3 170 124.6 120 110.9
Kenai paper birch ______________________ 20 20 6.2 20 6.2 0 0
P49-15: White spruce ___________________________ 290 290 194.2 280 194.0 190 169.6
Kenai paper birch. _____________________ 10 10 6.6 10 6. 6 10 6. 6
P50-15: White spruce ________ ... : .. _____________ 270 270 132.6 240 130.8 120 98.0
Black spruce ________ ------------------_ 245 235 26.1 120 19.3 0 0
Sitka alder---------------_______ .• _____ 310 70 (1). 0 0 0 0
P50-5, white spruce----------------------600 580 210.6 440 203.1 140 113.9
260-year-old stand, P49-6:
White spruce ... __ ----------------------370 370 225.4 270 221.2 170 195.9
Kenai paper birch-------------"·-------50 50 11.5 40 11.0 0 0
360-year·old stand, P51-21: White spruce ___________________________ 70 70 33.4 70 33.4 20 16.1
Black spruce _____ -----_________________ 700 380 14.6 10 1.4 0 0
1 Basal area not determined.
60 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Forest-canopy density tends to decrease with increasing st~nd age;
greatest density is usually encountered in forests less than 160 years of
age. In the subordinate vegetation the gTeatest density of cover is
found in the ground layer (0 to 2 inches) where values of 75 to 100
percent are usual. Lowest densities are found in the layers 1 to 2.5
feet and 2.5 to 6 feet above the ground where density is usually less
than 10 percent.
Maximum heights in the oldest spruce stands seldom exceed 85 to
100 feet and maximum diameters are seldom more than 20 to 24
inches. Average values are considerably less.
White spruce forests may be even aged or uneven aged, depending
on their histo_ry. Stands that seeded in burned areas are usually
even aged whereas those that originated as a result of entry of spruce
into other forest types, principally paper birch or quaking aspen,
more commonly are uneven aged. In all cases the number of age
classes increases with increasing stand age. Garman (4-7), working
in central British Columbia, wrote as follows: "The open nature of
the forest often found in the first generation after fire indicates that
eventually there will be an uneven aged forest, as a result of ·the
filling in process which will follow the elimination of aspen and birch
by spruce, but as the stands become older the age differences will
become less obvious."
Tree reproduction in most spruce stands was predominantly white
spruce. On the average there were about 3,700 seedlings per acre,
with a frequency of occurrence of approximately 50 percent on the
plots studied. Birch averaged about 600 seedlings per acre, with a
frequency of 40 percent. Spruce was the only tree species that re-
produced itself in numbers. Most of the birch seedlings and sprouts
died after a few years unless they were located in openings in the
forest canopy.
In addition to the willows already mentioned (Bebb willow, Salix
r;lauca var. aliceae, feltleaf willow, littleleaf willow, smooth littleleaf
willow, and Scouler willow) several other species were encountered
occasionally: Barclay willow, including var. rotundijolia, grayleaf
willow, S. glauca var. acutijolia, blueberry willow, park willow, net-
leaf willow, Richardson willow, and Walpole willow.
MosT ABUNDANT SHRUBS, ExcLUSIVE OF WILLows
Arctostaphylos alpina ssp. rubra
Cornus canadensis
Empetrum n1:grum
R?bes tr?ste
Rosa acicularis
Rubus pedatus (in stands more
than 160 years of age)
Faccinium vitis-idaea
Viburnum edule
These species have relatively high frequencies but relatively low
density of cover. An exception is Vaccinium vitis-idaea, which
commonly has coverage values in excess of 25 percent.
CoMMON SHRUBs
Ledum palustre ssp. decumbens
Shepherd1"a canadens1"s
V accinium uliginosum
,. -
'
'
.'
i./·
~
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA
OccASIONAL To· RARE SHRUBS
Arctostaphylos uva-ursi
Betula glandulosa
Cassiope tetragona
Menziesia jerrug1"nea
Potentilla jruticosa
Rubus alaskensis
R. chamaemorus
17 accinium cespitosum
Menziesia ferruginea tends to occur only in the oldest stands.
61
Grasses are scarce in spruce stands less than about 120 years old.
In general they are less well represented in spruce forests than in
stands representing earlier stages of succession. Calamagrostis can-
adensis is by far the most· prominent species, occurring widely but
sparsely. Density of cover is usually less than 5 percent.
GRASSEs, OccASIONAL To RARE
Agropyron lat1"glume
Agrostis scabra
Arctagrostis latifolia
Bromus arcth~us
Calamagrostis purpurascens
Festuca altaica
F. ovina
F. rubra var. lanuginosa
Phleum alpin?tm
Poa glauca
P. pratensis
Trisetum spicatum
Carex concinna is frequently encountered in the w.hite spruce forest.
GRASSLIKE PLANTS, OccAsiONAL To RARE
Carex bigelo1Vii
C. capillaris
C. disperma
C. media
C. scirpoidea
C. vaginata
Eriophorum vag1:natum
Juncus castaneus
Luzula parviflora
They are more often encountered in old than in young stands.
Many species of £orbs are found in the white spruce type.
FoRBs, MosT ABUNDANT
Comandra livida
Dryopteris disjuncta (in stands less
than 160 years of age)
Epilobium angustifolium
Equisetum arvense (in stands more
than 160 years of age)
E. pratense
E. scirpoides
Goodyera repens var. ophioides
Linnaea borealis var. americana
Listera cordata (in stands more
than 160 years of age)
Lycopodium annotinum (in. stands
more than 160 years of age)
Mertens1:a paniculata
Pyrola asarifolia var. incarnata
P. secunda
P. virens (in middle-aged stands)
Trientalis europaea ssp. arctica
(
FoRBS, OccASIONAL TO RARE
Ach~llea boreal1"s
Aconitum delphinifolium
Androsace lehmanniana
Arenaria laterijlora
Artemisia arctica
Aster sibericus
Astragalus alpinus
Boykinia richardsonii
62 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
FoRBS, OccASIONAL TO RARE-Continued
Castilleja pallida ssp. mexiae
Dryopteris austriaca (in old stands)
Equisetum sylvaticum
Erigeron purpuratus
Galium boreale
Gentiana propinqua
Hedysarum mackenzii
Lupinus arcticus
L. nootkatensis
Moneses uniflora
Orchis rotundifolia
Oxytropis campestris var. varians
Parnassia kotzebuei
P edicularis labradorica
Petasites jn'gidus
Pyrola grandijlora
Rumex arcticus
Sanguisorba stipulata
Saussurea angustijolia
Senecio atropurpureus ssp . .frigid11s
S. integerrimus
Solidago multiradiata
Stella ria longi pes
Streptopus amplexijolius
Tofieldia cocc~·nea
T. pus~·ua
V aleriana capitata
Zigadenus elegans
Mosses are characteristic of the ground cover vegetation in the
white spruce type. Two species are especially prominent in stands
over 50 years of age'; these are Hylocomium splendens and Pleurozium
schreberi. Commonly one or both of these species has a· coverage of
25 to 100 percent. Dicranum juscescens is also an abundant species,
usually appearing in stands between 50 and 200 years of age. Dre-
panocladus uncina.tus is most prom.inent in stands less than 120 years
of age, and Polytrichum commune and P. strictum occur most abun-
dantly in stands more than 150 years of age.
MossEs, CoMMON
Aulacomnium palustre
Brachythecium albicans
Ptilium crista-castrens1's
Mnium affine
Rhytidium rugosum
Tomenthypnum nitens
MossEs, OccASIONAL TO RARE
Brachythecium salebrosum
Bryum caespiticium
B. cuspidatum
Calliergon stram~·neum
Camptothecium lutescens
Ceratodon purpureus
Dicranella grevilleana
Dicranum bergeri
D. elongatum
D. fragilijolium
D. muhlenbeckii
Ditrichum fiex~·caule
Eurhynchium substrigosum
Hypnum imponens
H. lindbergii
Leptobryum pyriforme
Meesia uHginosa
Oncophorus wahlenbergii
Pohlia nutans
Polytrichum ,juniperinum
P. strictum
Rhytidiadelphus triquetrus
Sphagnum capillaceum
S. girgensohnii
Tetraplodon mnioides
Thuid~·um delicatulum
Timmia austriaca ·
Tortella fragilis
The liverwort Ptilidium ciliare is encountered occasionally.
The most abundant lichens in spruce forests are Peltigera aphthosa
var. typica, P. aphthosa var. variolosa, and P. membranacea. They
occur on the majority of plots. · ·
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA
LICHENs, CoMMON
Cetr:aria cucullata
C. nivalis
Cladonia .amaurocraea f. celotea
C. coccifera
C. cornuta f. cylindrica
C. gracilis var. dilatata
C. gracilis var. elongata
C. mitis
C. rang~ferina
C. sylvatica
Stereocaulon paschale
S. tomentosum
.LICHENS, OccASIONAL To RARE
Cetraria hiascens
C. islandica
C .. iuniperina
C. tilesii
Cladonia alpe~tris
C. amaurocraea f. jasciculata
C. amaurocraea f. oxyceras
C. cariosa
C. cariosa f. corticata
C. cariosa f. squamulosa
C. chlorophaea f. simplex
C. corn uta f. scyphcsa
C. dejormis
C. degenerans f. cladomorpha
C. degenerans f. euphorea
C. degenerans f. gracilescens
C. multiform~·s f. finkii
C. pseudorangiformis
C. pyxidata var. neglecta
C. rangiferina f. stygia
C. scabruiscula
C. scabruiscula f. surrecta
C. uncialis
C. verticillata f. evoluta
. Dactylina arctica
D~~ploschistes scruposus
Dujourea madreporiformis
Nephroma arcticum
N. expallidum
Ochrolechia .frigida
Peltigera canina
P. canina var. rufescens
P. malacea
63
C. jurcata var. racemosa f. corym-
bosa
C. gracilis var. chordal is
Stereocaulon paschale var. alpinum
f. gracilentum
C. gracilis var. chordalis f. platy-
dactyla
In the older stands the beard lichens Usnea comosa ssp. r;omosa,
Alectoria jubata, and Lobaria pulmonaria are commonly seen. Evi-
·dently about 40 years must elapse after a fire before the so-called
reindeer lichens reappear. In general, species of Cladonia tend to be
more common in stands less than 170 years old than in stands past
that age. Lichens are, for the most part, plants that :flourish in
relatively open habitats. Lynge (84-) mentioned the lack of lichens in
dense Picea excelsa forests in Norway.
Essentially pure stands of white spruce are regarded as the climax
type on reasonably well-drained soils in the Alaska interior (fig. 19).
This tree has all the attributes of a species characteristic of terminal,
self-perpetuating (climax) communities. Various stages of succession
to this climax may be observed.
MacKenzie recorded what is probably the earliest observation of
forest succession following fires in northwesterp America. On his
journey down the river which now bears his name he made the follow-
ing entry in his journal (87, p. 24-) in June 1789:
The current is very strong, and the banks are of an equal height
on both sides, consisting of a yellow clay, mixed with small stones;
they are covered with large quantities of burned wood, lying on
349169-56-5
64 TECHNICAL BULLETIN 1133 , U. S. DEPT. OF AGRICU LTURE
F-477373
FIGURE 19.-A 150-y ear-old climax white s pruce stand on a s outhwest slope.
The dominants are 9 to 16 inches d . b. h. and 70 to 85 feet tall.
the ground, and youn g poplar trees, that have sprung up since ·
the fire that destroyed the larger wood. It is a very curious and
extraordinary circumstance, that land covered wi th spruce pine,
and white birch, when laid waste by fire, should subsequentl y
produce nothing but poplars, where none of that speci es of tree
were previously to be found.
The curious and extraordinary circumstance which l\1acKenzie so
accurately observed was an example of forest succession now recognized
as most common. In 1889 Bell (11), also writing of conditions in
Canada, was even more explicit in his statement of vegetational
changes occurring following fires. He wrote:
The following is the course of events after a fire h~s run through
a tract of the full-grown northern coniferous forest, the fires
always occurring during the driest part of the summer: In the
next spring weeds and bushes (raspberry, huckleberry, r ed elder,
etc.) begin to spring up and partly occupy the blackened ground.
These increase for two or three years, and as they die out are
gradually replaced by the poplars, white birch, pigeon cherry,
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 65
willows, etc., with a few conifers. The willows and pigeon cherrv
are short lived. The poplars attain their full size and decay in
about seventy years, and the white birch shows signs of old age
in l ess than one hundred years. In the meantime the proportion
of conifers is constantly increasing from new individuals springing
up , so that by the time the deciduous trees have died out the
ground h as become compl etely occ upied by the former.
Chambers (31), in discussing the work of Dr. George M. Dawson in
the MacKenzie Basin, wrote as follows:
In its primitive state, the surface \<.ras probably covered with a
dense and heavy growth of coniferous trees, principally the spruce
(Picea en gelmanni and P. alba), but with scrub pine (P inus
contorta) in some localities, and interspersed with aspen and cot-
tonwood . These forests having been destroyed by fire , a second
growth, chiefly of aspen, but with much birch in some places,
and almost everywh ere a certain portion of coniferous trees-
chiefly spruce-had taken its place. The aspen being a short-
lived tree, whil e the spruce reached a great age and size, the
natural course of events, if undisturbed, would l ead to the
reestablishment of the old spruce forests.
From descriptions of Nuttonson (103) and others, it may be concluded
that forest succession in Siberia is similar to that in northern Canada
and Alaska.
Singl e light surface fires in a white spruce forest do not result in
complete destruction of the stand. Openings are created, however ,
and birch, and occasionally willows and aspen , appear. Changes in
forest composition thus induced are relatively small. Singl e light
surface fires usually do not result in a complete change in the forest
type. Saari (133) in Finland showed that the average damage per
unit area of fore s t burned, or the absolute destructiveness of fires , is
greatest in the spruce, because it is damaged very easily. He found,
as might be expected, that complete destruction of the main stand
was most common in young forests and, conversely, that in some
instances the main forest stand was undamaged .
Singl e severe fires generally result in compl ete destruction of the
existing stands and replacement by communities of sub-climax species.
The composition of the new stand is primarily dependent on the seed
sources adjacent to the burn. If t h e area burned was extensive and
if all white s pruce seed trees are killed, the reproduction will consist
largely of aspen, paper birch, and cottonwood. These species are
widely disseminated by wind . If aspen trees were present in the
stand destroyed, the species will be heavily represented in the new
stand because aspen reproduces abundantly by root suckers. Hol-
man and Parker (63) regard light spring or early summer fires in the
Prairie Provinces of Canada as less likely to result in good spruce
reproduction than severe l ate summer or early fall fires. They
stated: ,
Where fire or lo gging has oc curred and not removed moss , duff ,
or debris to a compact moisture-retaining seedbed no reproduc-
tion has occurred [in Alberta], even though s ufficient see d trees
have been left. ·where fire or lo gging has occurred and has re··
sui ted in the removal of moss, duff and debris, reproduction has
66 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
always occurred, if an adequate seed supply was available. In
late summer and fall fires the seed supply may be in the form of
cones on the trees that have been killed, but even this appears
in most cases to be adequate for the purpose of restocking.
Black spruce may be strongly represented in the reproduction follow-
ing fire in white spruce on upland areas. This migration of black
spruce from its normal lowland habitat to fireswept uplands has al-
ready been mentioned. Occasionally reproduction of essentially pure
white spruce may become established following fires in the climax
type. This occurs most frequently when the burned areas are rela-
tively small and are surrounded by, or are adjacent to, living trees
of seed-bearing age.
Shortly after a severe fire has swept through a spruce forest, the
dead trees begin to fall, creating a tangle of flammable material
that is difficult to penetrate. The result is that the fire hazard is
greatly increased. Fire-killed snags usually do not remain standing
as long in theN orth as in regions to the south. The trees are generally
shallow rooted with most of the roots in the forest floor and upper-
most horizons of mineral soil. Fires burn most intensely and deeply
around the tree bases with .the result that the prop roots are burned
off. Following a fire the/ hazard due to fallen snags gradually in-
creases for 5 to 10 years and then slowly decreases during the follow-
ing 10 to 20 years. The rate of decay varies with aspect and ground
conditions, as well as with the size of the material. In general, how-
ever, snags do not constitute much of a hazard 20 to 30 years after a
fire. Much of the timber killed by the great fire on the Kenai Pen-
insula in 1947 is already on the ground. There the fire hazard will
remain abnormally high for many years.
The frequency of burning has an important bearing on the compo-
sition of the plant communities that develop. Areas that once sup-
ported white spruce have become treeless as a result of repeated fires.
A dense cover of fireweed and grass (chiefly Epilobium angustijolium
and Calamagrostis canadensis) now occupies areas that previously
supported forests. The fireweed and grass, together with other
herbaceous plants, often produce an unbelievably rank growth, fre-
quently attaining a height of 5 to 6 feet. This presents an effective
barrier to the re-entry of tree seedlings. In the spring, before new
growth has started, the mat of litter representing the previous year's
growth may be 6 or more inches in thickness. Beneath this mat
may be found a layer of humus 8 or more inches thick, resting on
mineral soil. The mineral soil in such situations sometimes exhibits
the leached A2 horizon of a podzol profile developed under forest
cover. Fireweed-grass communities when well developed appear to
be relatively stable; natural reconversion to forest, where this occurs,
evidently requires 100 to 200 years. Pohle (119), in his studies on
the Kanin Peninsula in northern Russia, found that openings created
in the forest by fires supporteP. a luxuriant growth of herbaceous
plants. He pointed out that this growth may develop so early in
the spring that its density prevents the development of tree seedlings.
Another change in vegetation type is from a forest to a shrubby
cover of dwarf birch and willows. This community is evidently not
as stable as the fireweed-grass type. Re-entry of tree species, espec-
ially spruce, seems to occur more readily,
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 67
The effects of fire on forest vegetation are most severe on the
poorest sites. In general, the change in vegetation is most profound
and subsequent recovery most slow on steep slopes having southerly
or westerly exposures and on rocky or ledgy areas where mineral soil
is shallow or nearly lacking. Forest recovery from fire is dangerously
slow at the upper a.Ititudinal and latitudinal limits of forest growth.
Pohle (120) investigated the tree and forest limits in northern
Russia. He stated that if the forest at its northernmost limits is
opened up, tundra vegetation, which characteristically has high
light requirements, may enter and flourish. The tundra vegetation
can be held in check only if immediately following the disturbance
to the forest there is a good tree-seed year, that is, only if a new stand
of young trees again shades the ground: Prompt return of tree
growth .in such areas, however, is probably the exception rather than
the rule because near the limits of tree growth seed years occur very
infrequently. Pohle observed that in the majority of cases the
tundra vegetation becomes established as a relatively permanent
community. Hustich (64) issued a warning relative to the care needed
in managing the northern forests in Labrador, and referred to "the
warnings expressed by North-European forest scientists against an
exploitation of the northernmost forests, just because of their few
seed years and slow regrowth."
Fires in the northern forest have sometimes exercised a beneficial
effect in providing conditions for· establishment of rapidly growing,
healthy forest stands. Gilmore (48) stated that burned areas in
Newfoundland support better stands of spruce than do areas of
virgin timber where there has been no fire for a very long. time. He
found the percentage of spruce higher and the rate of growth better
on burned areas than where fires had not occurred. Rubner (132), in
discussing forest conditions in Finland, remarked that those familiar
with northern forest conditions recognized that fires may have favor-
able effects; he stated that the best spruce and pine stands occur on
former burns. After detailing the effects of fire in Scandinavia,
Tamm (151) wrote as follows: "The forest fire with its consequences
has thus in north Sweden usually been nature's own and very satis-
factory method of regeneration, especially in respect of the Vaccinium
forests but also of other forest associations."
Recognition of possible past benefits of fire, whether in the Coast
Douglas-fir region or in the white spruce forests of the high North,
does not mean that uncontrolled forest fires can now be condoned.
Fire is a-poor master but, under control, may be a good servant.
Black Spruce Type
Black spruce usually occurs in situations where drainage is poor
and permafrost is close to the soil surface. Stands of this species
are generally encountered in relatively fiat valley ,bottoms, on fiat to
gently rolling land, and on cold slopes having! a north exposure.
Raup (124), working along the Alaska Highway, thought that on the
more or less level terrain there was a fair coincidence between the
occurrence of black spruce and soils derived from clays or clayey
glacial tills. The species may also invade upland areas normally oc-
cupied by white spruce (fig. 20). This occurs following fires when a
6 'l'ECI:tJ\fiCAL BULLETIN 113 3, U . S . DEP'l'. OF AGRICULTURlil
F -47736 1
FI GURE 20.-A 55-year-old stand of black s pruce . Domina.nts are 2 to 4 inche . .;
d. b. h. and about 15 feet tall. Snags a r e r e licts of 2 fir e-kille d stands . The
last fir e killed a pole stand of black s pruce and an earlier fir e killed a stand of
white s pruce containing trees 10 t o 12 inches d. b. h . This is an example of
black s pruce replacing white s pruce, following repeated fires.
source of black spruce seed is available and white spruce seed is lack-
ing . Black spruce is regarded as a fire species because it reproduces
abundantly following fir es, mo stly from seed stored in t h e persistent
cones.
Tree composition in the black spruce type is shown in table 9.
Characteristically, black spruce forms pure stands. Normally it grows
in wet, poorly drained h abitats and competition from other tree
species is slight. P erhaps eq ually important in accounting for the
pure stands is the generally abundant supply of black spruce seed .
L ess important is the ability of black s pruce to reproduce vegetatively
by layering. Oc casionally one encounters individuals of ·white spruce
and paper birch, but they form a very minor component in most
black s pruce stands. Grayleaf willo w and littletree willow occasion-
ally attain a diameter of 1 inch or more and a h eight exceeding 6 feet
but their occurrence is limited.
Stand densities are very high in young black spruce stands; there
often are 5,000 stems 1 inch or more in diameter p er acre in stands
30 years of age and old er. Even in stands 100 years of age and older,
there may be a total of 2,000 to 3,000 stems per aere with 200 to 300
trees 5 or more inches in diameter.
Forest-canopy d ensity appears to d ec rease slightly after stands
attain an age of about 200 years; in stands up to 100 to 150 years old,
crown d ensity is high. In the s ubordinate vegetation, greatest
d ensity of coverage is seen in the ground layer (0 to 2 inch es) where
d ensities approaching 100 percent a r e us11al. Lowest densiti es are
:ECOLOG ICAL EFFECTS OF FOREST FIRES IN ALASKA 69
encountered in the layers 1 to 2.5 feet and 2.5 to 6 feet where coverage
is usually l ess than 5 p ercent.
Maximum h eights in mature black spruce fore s ts u su a lly do not
exceed 45 fe et and maximum diam eters are seldom more than 8 to
9 inches. Young black spru ce stands, originating following fir es,
a r e u sually even aged . In stands past 100 y ears of age, however ,
they tend to b ec ome increasingly more uneven aged.
T ABI,E 9.-Composition of black s pmce stands in interior Alaska: Nwn be1· of h ee><
and basal mea p er acre , by stand a ge, species, and diarneter (bre a s t high ) gro1tp
St:1 nd age , plot numher, and specie s
rr ree s
per acre
Diameter 2
inche' a nd up
Diameter 5
inches and up '
1 inch 1 --~---1 ---~-and up
in
diam-
eter
rl'rces B asal J~~~ a r e~ T r ees B a sa l
~c~~ area
---------------------1---------------
30 -yea r-old stan d s :
P49-28, black spruce --------------------------------------
P.>L-2~: Black s pruce . __________________________________________ _
White spruce .... ----------------------------------------55 -yea r-o!d stand, T 50-5: Black s pruce . __________________________ ·---____________ _
White spruce . ___ , _____ ----------------------------------
80 -year-old stand , P50-25:
Black s pruce . _______________ --------------___ ------____ _
White 'pruce .-------------------------------------------
Gray leaf willow. ______________ -------------------------
Littletree willow ____ ------------------------------------
85-year-old stand , P51-23:
B lack spruce . __ ._-----_-----__ -----____________________ _
White spruce. ________________ ------____________________ _
100-year-old stand, P51-28:
B lack s pruce . _________________________ ---------________ _
A lask a paper bir ch .-------------------------------------
200-ycar-old sta nd, P 50-19, b lack s p ruce ___________________ _
' No t r ees r eached 10 inch es in diameter.
No . No.
4, 900 2, 11 0
4, 64 0 44 0
20 20
1, 300 72.=)
25 2.1)
7~0 690
20 20
730 0
40 0
5, 960 3, 640
20 20
2, 910 1,8 10
20 20
1, 960 1, 825
S q.ft. No. Sq.ft.
82.9 40 G. 7
11 .3 0
1.0 0
20.8
1.2
Gl. 3 200 37. l
3. 5 10 2. 7
0 0 0
0 0 0
14?.1 20 2. 7
2. 7 20 2. 7
128. 6 300 51.2
1.0 0 0
122.4 195 28. 7
R epro duction is confined to black spruce. Practically all stands
have reproduction es tablished, with an average of around 4,100
s ee dlings and l ayers p er acre . Willows of all kinds (l ess than 6 f eet in
height) average about 4,700 stem s p er acre. No one speci es is pre-
dominant, exce pt lo cally. The follo wing species are represented.
Litt l etree willow , smoo t h B ebb willow, grayl eaf willow , its var.
acutijoli a , and var . alic eae, blueberry willow, diamondleaf willow , n et-
leaf willow, and Scouler willow.
MosT ABUNDANT SHRUBs, O THER THAN WILLows
Arctos taphylo s alpina ss p . rubra
Empetrum nigrum
L edum palustr e ssp. gro en la ndicum
Ro sa acicularis
V accinium ul·iginosum v. mtis-idaea
S HRUBS, O ccASIONAL ·ro R A RE
{
B etula glandulo sa
B. nana ssp. exi tis
Oassio pe tetragona
Oornus canadensis
L edum palustre ss p . decum be11s
Menziesia f erruginea
Oxycoccus m icroc arpus
Potentilla j ruticosa
Rhododendron lapponicum
Vaccinium cespitosum
70 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Grasses are unimportant in the black spruce type. Arctagrostis
latijolia is perhaps the most frequently encountered species. Oc-
casional to rare are Calamagrostis canadensis, Festuca altaica, and Poa
paucispicula. ·
Of the grasslike plants, the sedges are occasionally encountered but
are not at all common. Carex lugens perhaps is seen more frequently
than any other species. Carex canescens, C. vaginata, Eriophcrum
brachyantherum, E. vaginatum, and Luzula rufescens are occasiona.l to
rare. The grasslike plants appear to be slightly more frequent in
stands more than 60 years of age than in young stands.
The most abundant forbs in black spruce stands are Equisetum
scirpoides, Petasites jrigidus, and Pyrola secunda.
FoRBS, OccASIONAL To RARE
Astragalus alpinus
Chrysosplenium tetrandrum
Epilobium angustifolium
Equisetum arvense
Linnaea borealis var. americana
Mertensia paniculata
Pedicularis labradorica
Pyrola asarifolia var. incarnata
Rumex arcticus
Saussurea angustijolia
Saxifraga hieracifolia
Senecio integerrimus.
Mosses are a characteristic component of the vegetation in the
black spruce forest. They often completely cover the surface of the
forest floor. Most common is Hylocomium splendens.
MossEs, LEss CoMMON
Aulacomnium palustre
Dicranum drummondii
Drepanocladus uncinatus
Pleurozium schreberi
Sphagnum rubellum
Tomenthypnum m·tens
Sphagnum mosses, practically lacking in other forest types, are
characteristic of black spruce stands, especially in the older age classes.
MossEs, OccAsiONAL TO RARE
Aulacomnium turgidum
Dicranum elongatum
D. juscescens
D. majus
D. strictum
ll.7Jpnum dieckii
Polytrichum commune
P. juniperinum
P. strictum
Sphagnum girgensohnii
S. plumulosum
Although a considerable variety of lichens occur in the black spruce
type, they usually do not occupy appreciable areas of the forest floor.
Coverage is usually less than 5 percent.
LICHENs, MosT CoMMON
Cladonia coccifera
C. cornuta f. cylindrica
C. degenerans f. euphorea
C. gracilis var. dilatata
C. mitis
Peltigera aphthosa var. aphthosa
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 71
Cetraria cucullata
G. islandica
Gladonia alpestris
LICHENS, OccAsiONAL To RARE
G. rangiferina
G. amaurocraea" f. celotea
G. amaurocraea f. oxyceras
G. cenotea f. crossota
G. crispata var. i'tlfundibulifera
G. crispata var. V'irgata
G. deform1"s
G. degenerans f. cladomorpha
G. gonecha
G. rangiferina f. stygia
G. scabriuscula f. sublems
G. sylvatica
G. unc1"alis
Dactylina arctica
Nephroma arcticum
Peltigera aphthosa var. variolosa
P. can1"na
P. canina var. rufescens
P. pulverulenta
In the older stands, beard lichens such as Alectoria jubata and
Usnea comosa ssp. comosa occur commonly on the trees.
Black spruce represents a physiographic climax on cold, poorly
drained soils in the forested region of the Alaska interior. Here it
represents an essentially stable, self-perpetuating community, repro-
ducing itself by both seedling growth and layering. The type also
occasionally occurs on moderately well-drained uplands where, as
a result of fires, it has replacedwhite spruce. In these situations it
must be regarded as a temporary fire type which will, in the course
of time, give way to white spruce.
Fires in black spruce are often intense, completely killing the
vegetation and consuming the forest-floor material. The high stand
density and relatively low stature of the trees favor crown fires.
The flammability is often increased by the presence of beard lichens
(principally Alectoria jubata and Usnea comosa ssp. comosa) on the
trees. These lichens are tinderlike when dry.
The black spruce type usually regenerates itself following fires.
Millar (97) reported this tendency in Ontario, Canada. He found
that, following fires, the stands were not radically different from the
climax. type. Repeated burning at short intervals may result in
replacement of the black spruce by treeless communities such as
sedge-rush-grass or low shrub. These may persist indefinitely because
of the difficulty of establishment of spruce seedlings. In areas where
the. ground water is close to the surface, destruction of forest vegeta-
tion is lmown to result in a rise of the water table, producing swamp
conditions (22, 55, 164).
EFFECT OF FIRE 'oN SOILS
In a region such as the interior of Alaska, where forest fires each
year burn over extensive areas, it is natural that questions should
arise as to influence of fires on soils. The problem has attracted
attention in almost every country in the world. Investigators in the
Scandinavian countries and in the United Sta1ies, particularly, have
done much to improve our knowledge of the subject.
The interior of Alaska has many kinds of soil, how many no man
knows. Soil classification and inventory in Alaska are in their
infancy. The principal reports on Alaskan soils are specifically
designated as being of a reconnaissance character (12, 13) or of an
72 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
exploratory nature (68). Nevertheless, certain statements may be
made on the basis of present scanty information.
In general the soils in the interior of Alaska are shallow, both in the
sense of soil development and in a physiological sense; many are young.
Under forest vegetation, soil temperatures are low, even above the
frozen ground which, during August, may be encountei·ed at depths of
as little as 1 to 2 feet. This is especially true in dense spruce forests
having a well-developed forest floor. The low temperatures inhibit
chemical weathering of the soil material, reduce to a low level the
activity of soil organisms, and unfavorably affect physiological
processes in plant roots.
From the standpoint of mechanical composition, many, if not most,
soils contain relatively little clay. This is probably a reflection of the
slowness of chemical weathering and the youthfulness of the soils.
Many of the soils possess upper layers with a high proportion of very
fine sand and silt, fractions that appear to have been brought in by
wind. The surface soil is often fluffy when dry; cohesion is weak,
and aggregates, if present, tend to be small and soft. Weak platy
aggregates are sometimes seen. Internal soil drainage, under natural
conditions, is usually slow to poor. Frozen ground at shallow depths
commonly produces, in effect, a perched water table. Some soils
have developed over coarse gravelly or cobbly alluvium; these tend
to be so excessively drained that natural vegetation such as quaking
aspen and balsam poplar defoliates during the middle of the summer
because of water shortage.
In the majority of forest soils in the interior there appears to be
relatively little leaching due to low precipitation, and the depth to
frozen ground is relatively shallow. Leaching seems to be greater in
soils south of the Alaska Range than to the north. Well-developed
podzols occur in many places on the Kenai Peninsula, in the Susitna
Valley, and in the Copper River Valley. North of the Alaska Range,
podzols are weak and encountered only occasionally.
The organic matter tends to be unincorporated with the mineral
soil, resting on it as a mantle. Thickness of the unincorporated
organic matter varies from 2 to 4 inches in birch, quaking aspen, and
balsam poplar stands to 4 to 6 inches in spruce forests. Under old
white spruce, and especially in black spruce, the layers of organic
matter may be 12 inches thick. The general lack of incorporation
of organic matter into the mineral soil appears to result from the
scarcity of soil animals such as earthworms and large arthropods.
In fact, no earthworms were found in undisturbed forest soils in the
interior of Alaska. ·
The layers of unincorporated organic matter in undisturbed forests
are moderately acid; pH values are often about 4.5 south of the Alaska
Range. In sections where the precipitation is lower, values of around
6.0 have been found. An indication of the variation in Alaskan soils
is found on an aspen-covered southerly slope near Sheep Mountain
in the upper Matanuska Valley, where a gray or white zone of calcium
carbonate accumulation may be plainly seen. The material effer-
vesces vigorously when treated with dilute acid and has a pH of 8.32.
Acidity commonly decreases with increasing depth in the soil body.
In general,· the supplies of calcium are high. Potassium, phos-
phorus, and nitrogen appear to be adequate for normal forest pro-
ECOLOGICAL EFFECTS OF FO!l-EST FIRES IN ALASKA 73
d'iiction. . As might be expected, most of the nitrogen and available
phosphorus is associated with the organic matter. The available
phosphorus content is relatively high in the organic layers, low in the
mineral soil layers exploited by roots, and high in the subsoil below
the main root level. This distribution probably results from absorp-
tion of the element by plant roots in the upper mineral soil layers
and its return to the humus laver in the annual leaf fall. Root devel-
opment in most soils is shallow.
Water relations are especially important in the forest soils of interior
Alaska. If the topographic situation is such that the soils are sup-
plied with an abundance of water, subject to only very slow lateral
movement, unfavorable ecological conditions result. Frozen ground
is likely to be encountered at shallow depths, a waterlogged condition
exists, temperatures are low, and aeration is poor. Tree growth is
slow, if trees occur at all. On the other hand, soils that are supplied
with small amounts of water are likely to be excessively droughty.
It must be remembered that precipitation is scanty in the interior.
The most favorable conditions for tree growth are often found
adjacent to waterways where the depth to frozen ground is several
feet during the growing season, and where the ground water is moving,
aeration is favorable, and soil-temperature is adequate for normal
growth. Pohle (119) noted the occurrence of forests along streams
in northern Russia and suggested that the width of the timbered
strip was dependent on drainage. Drainage is better in relatively
coarse-textured soil materials (and the width of the timbered strip
is greater) than in fine-textured soil materials. Evidently the width
of the timbered strip along waterways becomes narrower with increas-
ingly high latitudes.
Frozen ground is a common feature in soils of the Alaska interior.
It is not present everywhere, however, and where it occurs its depth
below the soil surface varies considerably influenced by drainage,
topographic exposure, and vegetation type. Benninghoff (14) stated
that seasonal thaw under spruce forests usually ranges from 2 to 6
feet. Thawing extends to greater depths under paper birch, quaking
aspen, and grass. In general, it may be said that the existence of
permafrost is a most fortunate circumstance. Thawing permafrost
provides the vegetation with water that otherwise is not available
because of the scanty rainfall. Without this water source large areas
in.the Alaska interior would, in all probability, become desertlike.
Humus Layers
The effect of fires on the thickness of the layers of unincorporated
organic matter varies with the intensity and frequency of burning.
Light fires consume only the uppermost litter but severe fires may
expose the mineral soil surface over all, or nearly all, of the burned
area. Repeated light fires may be just as effect~ve in destroying the
forest floor as single severe fires. Complete destruction of the un-
incorporated organic matter was most frequently observed on well-
drained rocky slopes or ridges where fuel and atmospheric conditions
favor intense burning. It was also observed around the bases of
spruce trees where the forest floor was dry because of interception of
precipitation by the crowns (fig. 21). As explained earlier, accumula-
7 4 TECHNICAL BULLETIX 113 3 : U . S . DEPT. OF AGR ICULTURE
F -477375
FIGURE 21.-D eep burning a round the bas e s of "·hite s pruce con s umed all unin-
corp orated organic matter. The mineral s o il is covere d with a layer of nearl y
pure a s h .
t io n of co n e scales a nd other highly flammable debris around t h e bases
of spruce t r ees is a factor favoring hot fir es . D estruction of t h e for est
floor to mineral soil varied from 0 to 100 percent in different fir es and
on diff er ent areas within a given burned tract. Examination of r ecen t
burns indicated that de ep burning to mineral soil involved about 30
to 40 p ercent of th e surface, even in fires so sever e as to kill all t r ees .
Physical Properties
Temperature
No m eas urements of temperatures attained during forest fir es are
available for Alaska but indications are that they a re high. Living
spruce roots up to about 10 in ch es in diameter have been burned off
and high temperatures have reddened both surface soil and rock s .
Following fires, minenJ so il temp eratures are generally incr eased b e-
ca us e of the reduction or elimination of the uninco rporated organic
matter. In undisturb ed co ndition, this material is eff ec tive insulation.
Another r easo n for high er temp er atur es on burned areas is the fre-
quently darker co lor of t h e so il caused by ch a r coa l. The higher soil
temp er atures that occur following burning a r e a lmo st invariably re-
flected in a downward retreat of t h e permafrost layer. Frozen ground
often o cc urs at d epths of 12 to 18 inches under spruce fores t in mid-
summer whereas in adj acent burned a.r ea.s the depth may be greater
than that reached b y a 3-f oot soil auger. The increases in so il tem-
p erature following fires a r e regarded as eco logically favorabl e although
l ethal levels may b e r eac h ed at the so il s urface occasionally and tree
see dlings may b e killed.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 7 5
Moisture Relations
Complete destruction of the for est floor on steep slopes, particu-
la rl y those with southerly exposures , increases surface runoff and con-
sequently decreases the amount of soil water available to plants.
Increased evaporation losses also reduce the amount of available water.
Reestablishment of forest growth on such sites is slo w.
On land with gentle topography and on fiat areas soil moisture rela-
t ions do not appear to b e altered a pprecia bly by fires. The field
capacity of the mineral so il layers , as judged by moisture equival ent
values, is not much ch a nged. In burned areas the supply of moisture
available to plants is more st-able, and hence more favorab l e, in spots
where mineral soil h as b ee n exposed than where a mantle of charred
organic matter remains. Organic matter on the mineral soil surface
can hold large quantities of water, but this water is readily lo st
t hrough evaporation. This results in wide fluctuations in moisture
content that are very unfavorable to seedlings. Another considera-
tion of ecological importance is the fa ct that a l arge proportion of the
water held in organic m atter is so tightly bound that plants cannot
remove it; thus the wilting p ercentage is mu ch higher in organic ma-
terial than in most mineral soils.
In many areas of interior Alaska the froz en ground contains bodies
of ice in the form of l enses , veins, and blo cks. These ice masses are
often l arge and o ccur under extensive tracts. When the natural vege-
tation is removed , as in clearing land for farming, the ice melts and
the settling and caving produce a n unstable, pitted surface. Mull er
(100) and others employed the term thermokarst for irregular land
surfaces thus produced by the m elting of ground ice. He r eported
that "Thermokarst land forms a 1;e commonly produ ced by forest
fires, grass fires, d efo r estation, and stripping of the surface by man.
Removal of the vegetative cover results in a more intense so lar heating
of the ground, melting the ground-ic e and causing settling and caving
of the ground-"
Wall ace (163 ) investigated cave-in l akes in the Nabesna, Chisana,
and Tanana River valleys and r emark ed that "The effect of r emoval
of the vegetal cover has been d emonstrated in many places where
caving has taken place in ground that had b een cleared for construc-
tion purposes . In nat ure the initiation of a lake could result from
such an event as the overturning of a tree b y wind, with resulting
uprooting of the vegetal mat." Forest fire s mu::t b e a far more com-
mon cause of the melting of ground ice than windthrow of trees .
Texture and Structure
If any changes in soil texture occur as a result of fir es, the changes
are slight. To al ter texture there would necessarily· have to be
either fusion or baking of particles into l arger stable units or a break-
down of particles into small er units . Only rarel5r does either happen.
Mechanical analyses indicate that the surface soil material , often
deposited by the wind, has undergone little change in particle size
since its deposition . Structural changes in the mineral soil as a resul t
of forest fires also appear to b e slight or lacking. Aggregate develop-
76 TECHNICAL BULLETIN 113 3, U . S. DEP1'. OF AGRICULTURE
ment in most undisturbed mineral so ils is slight because of t h e lo w
co ntent of organic and inorganic co lloid s. The aggregates tend to be
both small and weak.
Rtmo./J and Erosion
Although quantitative information is lacking, i t a pp ears certain t h at
runoff is increased on steep slop es that have b een severely burned.
This r es ults from a combina tion of d ecr eased in£ltration rates and lo ss
of t h e forest floor t h at reduces the rate of overland flow. This matter
is examined in more detail in t h e section , Effect of Fire on Hydro-
lo gic Relations.
Erosion on burned-over forest l and is surprisingly small in s pite
of the fact that the so il properties would l ea d one to conclude that they
wer e eas il y eroded. Lack of extensive and severe ero sion may b e due
to the low precipitation, t h e lo w intensity of rainfall in individual
storm s, the long p eriod each year that the soil s ar e fro ze n and snow
cover ed , and the rapidity of revegetation of burned l ands. Within a
year or two following fires, mosses, liverwor ts, lich en s, and high er
plants usually d evelop , binding the min eral so il and pro tectin g it from
wind and water erosion.
Stream bank slumping following forest fires has been observed in the
N ort h by Preble (12 2), McKenna (86), and others. However, fir es
are no t a major cause of bank slumping along northern rivers ; bank
c u tting and slumping are common features on streams flowing t hrough
country long lmburned (fig. 22 ).
F -477376
FrG URE 22 .-Bank cutting along the T az lina River. Erosion of this type is very
co:nmon and is not r elated to forest fires. It contri butes to the silt load of the
rive r s. Vi e w upstream from a h igh bluff on t h e north s ide of the rive r, about
V2 mile above the Richardson Highway crossing. .June 1951.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 77
Locally, steep slopes may be subject to landslides and slumping after
the removal of forest vegetation. Muller (100) pointed out that a
common cause of such mass movement ". . . is the concentration of
ground moisture at shallo w depth, immediately above t he impervious
permafrost or over the frost table prior to the complete thawing of
the active l ayer." Safeguarding measures that Muller recommends
include avoiding deforestation and the planting of trees and grasses.
At least two areas of drifting sands are known to occur in Alaska,
one in the Kobuk River Valley and one north of Tok in the Tanana
Valley. Neither of these areas was examined. Consequently it is
not possible to judge whether destruction of natural vegetation by
fire may have been a factor in initiating the erosion cycle.
Chemical Properties
Soil acidity in the surface layers is invariably reduced by burning.
Where the humus layers have been consumed and mineral soil exposed
pH values of 6.5 to 7.5 are common. This results from ashing of
the organic matter, which is relatively rich in the alkaline earths,
calcium, and magnesium. Samples of pure ash from a burned white
spruce forest had pH values of approximately 8.4. Reduction in soil
acidity is a usual accompaniment of burning, as shown by the work of
Eneroth (44), Isaac and Hopkins (66), Kivekas (72), and many others.
Exchangeable calcium in the upper layers of the mineral soil is
greatly increased by burning, the increase often being severalfold .
This tendency is almost universal, having been reported by investiga-
tors in nearly all parts of the world. Exchangeable potassium and
readily available phosphorus in the upper mineral soil layers are also
increased by burning and this, too, has been reported by many
investigators.
Nitrogen contained in organic matter that is consumed by fire is, of
course, vol atilized and lost to the site. Consequently it is certain
that immediately after a fire the total nitrogen capital shows a re-
duction. However, all, or nearly all, evidence from northern forest
regions points to an increased availability of nitrogen to vegetation
following fires (59, 60). Burning usually induces nitrification in mor
humus layers . Even total nitrogen may increase to l evels higher than
before the fire. This may result from development of wild legumes
with nodules containing symbiotic nitrogen-fixing organisms or it may
result from increased activity of the free-living, non-symbiotic
Azotobacter and Clostridium bacteria. The favorabl e nitrogen
relations in most burned areas are confirmed by the dark green color
of the plants, their vigorous growth, and the abundance of nitrate
plants, such as fireweed and red raspberry.
Fires quickly make available the nutrient materials bound in organic
matter. Thus immediately after burning a large part of the nutrient
capital of the site is concentrated in the ashes r on and in the upper
mine:ral soil layer. A similar effect would result from adding fertilizer
material. Microorganisms become active and seedlings which b ec ome
established grow rapidly. Spruce seedlings established in burns may
actually grow faster than seedlings of the same age in nursery b eds.
78 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICULTURE
Soil Productivity
On most sites in Alaska, fire does not exercise a damaging effect on
the soil. If it did, a large proportion of the forest soils in the Alaska
interior would already be seriously damaged.
Certa.in categories of site are, however, unfavorably influenced and
the effects may be of a lasting nature. Rocky, ledgy sites, especially
on steep slopes, may be seriously harmed. Here the forest that existed
prior to the fire was rooted not in mineral soil but in humus that had
been built up over a long period of time. Destruction of the humus
means destruction of the soil itself. Following fires, steep slopes with
southerly or westerly exposures become critical sites for tree growth.
Surface runoff is increased, the p~rmafrost table is considerably
lowered, surface soil and air temperatures are raised, and water losses
through evaporation are increased. Such sites, for a long time, can
support only the hardiest of plants. They may remain treeless
indefinitely or bear open stands of slow-growing aspen. Re-entry of
spruce is an extremely slow process even though spruce may have
been the type present before the fire occurred.
No possible justification of uncontrolled wildfires can be found in
the realm of soil sc.ience. Such fires can never be justified or even
excused on the basis of beneficial effects on the soil, despite the fact
that fires may have favorable effects on certain properties. Con-
trariwise, the writer regards uncritical allegations of d~:struction of
the soil and deterioration of the soil as less than strong arguments
against uncontrolled fire~. Occasionally destruction of soil by forest
fires does literally occur but on the majority of burns destruction or
deterioration of the soil would be impossible to prove.
EFFECT OF FIRE ON HYDROLOGIC RELATIONS
The relation of forests and other vegetation to hydrology in the
interior of Alaska is poorly understood. Although quantitative data
bearing on the subject are very scanty, vegetation probably exercises
a considerable influence on the water regime.
Runoff in rivers draining areas of permanently frozen ground
represents a high proportion of the total precipitation. Alter (7)
stated that discharge measurements made by the Geological Survey
on the Yukon River indicate that the runoff exceeds 60 percent of the
precipitation. Shimkin (14-3), in his report on the Fort Yukon area,
remarked that "An outstanding characteristic of Arctic rivers draining
areas of permanently frozen ground is that the runoff from their
basin~ approximates 55 to 65 percent of the precipitation as opposed
to 15 to 18 percent for rivers in tempera.te area~, such as the Missis-
sippi." Shimkin noted that "This means that the flooding, eroding
and silt-carrying capacities of these rivers . . . are nearly four times
as great as might be indicated by normal experience."
Removal of the vegetation mantle as a result of fire may be expected
to increase the already high ratio of runoff to precipitation. Increased
amplitude between high and low water stages may also be expected.
The qualitative effects of vegetation removal may be anticipated
even though quantitative information is not available. Ellswbrth
and Davenport (4-3), in discussing the surface water supply in the
Yukon-Tanana region, wrote as follows: ·
ECOLOGICAL EFFECTS OF FOREST FIRES rN ALASKA 79
The moss that forms a heavy coating over most of the country
probably regulates the distribution of the run-off during the
summer as much as any factor. It is quite generally the opinion
among the older residents of the country that the flow of the
creeks does not hold up as well after a rain now as when work
first commenced. That probably is due in part to the fact that
the moss covering on the older creeks has been largely removed
by fires and other agents.
The same authors in their discussion of the Crooked Creek drainage
basin in the Circle district observed that:
The run-off from the area is less than from adjoining areas.
The creeks are liable to a very low minimum discharge and, owing
to the steep barren slopes, are flashy in character. Nearly all
the timber in the headwaters has been cut off and much of the
basin has been burned over.
Marshall (90) in describing placer mining in the Koyukuk region,
stated that the water problem was exceptionally serious because most
of the creeks are small and their vohime of water has been decreased
by removal of the forest vegetation. Marshall (90, pp. 173-174)
quoted at some length the views of an old timer on the upper Koyukuk
to the effect that carelessness with fire had resulted in widespread
burning of the forest and that, with its destruction, water supplies
for mining became scarcer.
Tundra and bog vegetation, as well as forested areas, must exercise
a regulatory influence on runoff. Auer (8), in his investigations of
peat bogs in southeastern Canada, noted that "The burning off of the
moss covering may have the effect that the surface of the peat bog
is no longer capable of detaining water of sudden rain, but the water
breaks through the peat bog in many places and flows away as rapid
rivulets."
The problem of water supplies in the Alaska interior will probably
become more acute as population increases and the Territory is de-·
veloped: With increased demands for water, it seems certain that
increased attention will be given to the hydrologic role played by
vegetation.
EFFECT OF FIRE ON ANIMAL POPULATIONS
One of the important resources of the Alaska interior is the wildlife,
especially the fur bearers and the big game. From it both the white
population and the natives derive very substantial economic benefits.
As early as 1908 Osgood (1 06) recognized this fact and expressed
himself as follows:
In addition to its inherent values game is of great pecuniary
importance to the country it inhabits on account of the money
spent there by visiting sportsmen. Not only are substantial
revenues derived through the direct sale ofihuntiJ;J.g licenses, but
considerable sums are distributed in the payment of travelling
expenses and in the employment of guides, packers, boatmen,
and others. To Alaska and Alaskans such considerations are
not without importance, for the development of this northern
Territory will in the long run require the utilization of every
349169-56-6
80 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICULTURE
resource. If lands unsuitable for mining or agriculture can, by
reason of the wild game inhabiting them, be made a part of the
permanent resources of the country, they have a substantial
value. If properly husbanded the game becomes a perpetual
source of pleasure and profit, whereas if ruthlessly sacrificed to
immediate desires the region now made attractive by it will lapse
into a comparatively uninteresting and useless waste.
More recently, the Canadian Bureau of Northwest Territories and
Yukon Affairs (25) published the following statement:
As the fur trade has been and will continue to be the main support
of the Indian population, and as forest-dwelling animals supply
the Indian with meat, it is felt that one of the greatest values of
the forests of the Northwest Territories lies in the habitat which
they provide for game and fur bearing animals.
The effects of fires on the wildlife resource are of vital importance to
the future of Alaska and its citizens.
The subject of forest fires in .relation to wildlife has many contro-
versial aspects. Much of the controversy appears to stem from failure
to distinguish between accidental wildfires, whose occurrence with
respect to time, place, and intensity is largely fortuitous, and pre-
scribed fires which may be used as a management tool. Although
generalizations are admittedly hazardous, informed opinion seems to
be that accidental fires, whose time of occurrence and geographic
location is determined by a chance lightning strike, a cigarette disc.
carded before it was out, or by the campfire of a careless individual,
cannot be regarded with favor.
In 1933 Aldo Leopold (81), the leading exponent of game manage-
ment in the United States at that time, wrote, "Any fire, however
light, of course makes a clean sweep of all ground nests and helpless
young. This loss of .nests and young is undoubtedly the heaviest item
in the direct mortality from fire. The peak of the fire season in
most regions is the peak of the nesting and fawning season." In 1923
Leopold (80) stated that" ... fire does no good to ganie which forestry
would not likewise do, and fire does enormous damage ·to game which
forestry would avoid." The significance of this observation is not
widely enough appreciated. In 1934, Dymond (41), in discussing the
conservation of game and fur-bearing mammals, expressed the view
that "The necessity of preventing forest fires is now universally
recognized, but it may be worthwhile adding that fire not only destroys
the forest as such, but eliminates the wild life and renders the burned
area unsuitable for a long period as a home for many species of game
and fur-bearing animals." Gabrielson (46) stated,
Rapid running forest fires, particularly crown fires, may be
very destructive to wildlife. If they occur in the nesting season
of birds, the broods of the year and often the breeding stock are
destroyed. Many parent birds, particularly those sitting on
eggs that are nearly ready to hatch, 'will stay on the nests until
suffocated or burned. . . . Generally speaking, however, on the
basis of present knowledge, fire is so great an enemy of both
wildlife and forests that there is an increasing amount of fire
patrol, both on public and on private forest lands. This should
in the long run be exceedingly beneficial to wildlife.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 81
Fur-Bearing Animals
Fur-bearing animals in general appear to be adversely affected by
most severe fires. This applies particularly to animals that are unable
to take refuge in water and in situations where the fires are repeated.
Small mammals, many of which serve as food for fur bearers, are
killed when fires destroy their habitats (4-5). The marten (Martes
americana) one of the most valuable fur-bearing animals in northern
forests, probably is more menaced by forest fires than any other fur
bearer. Seton (14-1, pp. 4-91-4-93, 4-97) regarded fires as especially
damaging to marten and expressed himself as follows: "A forest fire
of 100 square miles means the destruction of all martens within that
100 square miles. They cannot escape. The smoke pursues the
fugitives, and overcomes them. Their food is destroyed in the stricken
area." In 1922 representatives of one of the great fur-trading com-
panies in Canada, presumably the Hudson's Bay Company (1)
stated,
It is a common complaint of the Indian that fires have crossed
his 'marten,' or hunting grounds, with the consequent destruction
of all such game as marten, fisher [Martes pennanti], fox [Vulpes
julva], ermine [Mustela erminea], and lynx [Lynx canadensis].
This necessitates a 'change of venue' for his activities, or the
confining of his attention to the trapping of beaver [Castor
canadensis], otter [Lutra canadensis], etc., thereby reducing the
numbers of these animals more rapidly.
During the summer of 1950 the extensive fires northeast of Fort
Yukon were frequently lamented by Alaskans because they destroyed
the forests in what was reportedly some of the finest marten country
in the Territory.
Of particular interest in this connection is a report by Angus
Brabant (18), Fur Trade Commissioner of the Hudson's Bay Com-
pany, published in 1922. Brabant expressed the view that recurrent
forest fires were a threat to the fur trade. He observed,
Our returns from certain districts that have experienced the
devastation of forest fires, over what is but a comparatively
small part of the total area, have indicated a marked decline
in fur production for many years after the occurrence of fires.
These conflagrations have not only destroyed magnificent
stretches of Ca-nadian forest, sweeping away valuable timber
that will require a generation to reproduce, but they have
wiped out the food supply and the shelter of the fur bearers.
Brabant also stated, "The Company's experience is that the finest
furs are obtained in the most densely wooded districts." This inter-
esting observation is confirmed by others (1). Brabant (18) pointed
out that "The appalling losses to the fur trade which are traceable
to forest. fires affect a very considerable portion of our population,
the many thousands who earn a living as trappers, traders, fur
dressers and dyers, garment makers, merchants and salespeople."
Exceptions doubtless occur but it seems reasonable to assert that
the general effect of uncontrolled fires on fur bearers is unfavorable.
82 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICUL'l'URE
Moose
The opmwn is frequently expressed that forest fires create more
favorable conditions for moose (Alces americana) by destroying climax
stands of white spruce or stands of black spruce and permitting the
establishment of subclimax communities of willows, aspen, and birch,
together with other browse species. That changes in vegetation
almost invariable follow fires is readily observed. It is not nearly
so certain, however, that the species composition of the vegetation
which follows wildfires will be that most desired.
In 1953, Leopold and Darling (82), writing of Alaskan conditions,
observed, "The mere passage of a fire through timberland does not
necessarily create optimum conditions for moose. Some burns pro-
duce a grassland stage; others come back in pure spruce; many pro-
duce aspen with little birch or willow which are the most palatable
and productive browse plants." Already it appears that the great
burn of 1947 on the Kenai Peninsula, involving a net area of perhaps
one-quarter million acres, will have a short-lived value as a wintering
ground for moose because of the entry of spruce reproduction in quan-
tity, the failure of willows to appear in numbers sufficient to with-
stand heavy use, and the fact that most of the browse is aspen sucker
growth, which does not successfully withstand heavy browsing.
This situation is not unique. Although most often aspen and birch
come in after fire as pointed out earlier it is not uncommon for burned
areas to reproduce to essentially pure spruce forest. It should also
be recognized that establishment of browse species following severe
fires is not immediate; years may pass before burned areas again
support an appreciable amount of food for moose (109). It is doubtful
that moose can reproduce rapidly enough to utilize fully the browse
in extensive burns before it grows out of their reach. This would be
a problem in tree species such as aspen, birch, and the larger willows
such as Scouler and Bebb.
The studies by Cowan, Hoar, and Hatter (35) in British Columbia
led them to the conclusion that it is desirable for moose to have access
to " . . . older stands bearing well grown coniferous trees . . . "
in order that they may obtain certain nutrients. These investigators
reported that their study pointed "to the desirability of winter range
for browsing ungulates upon which there is a variety of palatable
species predominantly in an early stage of growth, but with an
intermixturec_of stands of other ages including areas bearing sub-
climax or climax associations, including palatable coniferous species.
The most desirable winter range for moose will be one well diversified
as to species composition and age of stands, but predominantly of
new growth following deforestation."
The preponderance of evidence favors the conclusion that moose
are today common or abundant in some regions throughout the
North where formerly they were rare or not known to exist. This has
been repeatedly asserted with regard to the Kenai Peninsula, a region
now famous for both the numbers and size of its moose. In 1901
Osgood (105) stated, "According to report the moose has but recently
appeared in the Cook Inlet region; the older Indians say no moose
were there when they were boys." Similar statements were made by
Roosevelt and others (131), Niedieck (102), Osgood (104), Dufresne
i:
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 83
(39), and Camp (24). Dufresne (39) described the situation as
follows:
In the year 1883 a forest fire raged for months on Kenai Peninsula.
Shortly thereafter the caribou herds vanished. Coincident with
this rapid passing of the caribou appeared the moose which were
practically unknown on the Kenai before the big fire. Today,
not a single caribou exists on the Peninsula, but the place is
famous for its moose herds. The explanation is riot complex.
Fire destroyed the lichens on which the caribou feed; fire produced
in its wake abundant growths of willow, birches, and cotton-
woods r~lished by the moose.
That moose were practically unknown on the Kenai Peninsula
before the fire_ of 1883, mentioned by Dufresne, may be doubted.
In the Tenth Census of the United States, 1880, Petroff (116) described
certain delicacies served at a native feast in Chkituk (on the north
side of the Kenai River, above the village of Kenai) and specifically
mentioned dried moose nose. In addition, he stated, "The variety
of native animals is very great .... The deer here is apparently a
larger cousin of the reindeer, the woodland caribou. Moose, single
and in family groups, can be found feeding through the low brushwood
and alder swamps." Abercrombie (4), in his report of 1884, quoted
Ivan Petroff, who was then in the Customs Service at Kodiak, as
follows: "Forage can be gathered in the vicinity of Fort Kenai during
the summer to keep the stock during the winter. The climate is not
more rigid than that of Montana. Moose abound, furnishing an
article of food preferable to beef." Petroff was familiar with the
Cook Inlet region and must have written the above statement not more
than a vear or two after the fire of 1883.
Karr1s 1887 report (67, p. 237) included a map with the Kenai
Peninsula labeled as supporting bear and moose. The Eleventh
Census of the United States, 1890 (159, p. 70), only 7 years after the
fire of 1883, contains a statement~ on the Kenai Peninsula, as follows:
"The forests and valleys of this region are still filled with numerous
droves of moose ... and furnish a rich hunting ground for the
Tnainas of Nikishka and Kenai." That moose were actually present
on the Kenai Peninsula at a very early date is demonstrated by the
findings of Laguna (75) in her excavations on Yukon Island in
Kachemak Bay on the south end of the peninsula. Moose bones
were found in four layers (Period I, II, sub-III, and IV) representing
four periods of habita;tion. ·
Fires, through their effect on vegetation, probably favor an increase
in the population of moose, but there is no proof that burning was
uncommon on the peninsula prior to 1883. Apparently the earliest
written record of a forest fire in Alaska is that of the Russian mining
engineer Doroschin (37), who ascended the Kenai River in 1850.
He encountered a forest fire which prevented him from completing his
investigations of the gold resources of the regi<jn.
The available history of moose on the Kenai Peninsula was in-
vestigated because the presence or absence of fires does not satisfac-
torily explain the appearance and disappearance, or the existence of
large or sparse populations of these animals. In this connection it may
be pointed out that in the discussion of the paper by Chatelain (32)
84 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Urban C. Nelson remarked, "I think probably the conclusion that
the moose abundance there [on the Kenai Peninsula] is purely the
result of burns might be open to question."
Movements of moose into areas where they were previously rare
or not known to exist has extended to sections not influenced by fire.
Leopold and Darling (82, p. 87) stated,
On the northern and western fringes of the Alaskan moose range,
willow is not a secondary plant invader but rather it is part of the
riparian climax vegetation, the uplands being tundra. The
factor which governs the abundance of willow here is not fire,
as in the central and southern spruce forests, but probably
temperature. We" postulate that the recent spread of moose
into predominantly tundra areas must be correlated with the
gradual Holarctic warming that is known to have occurred
in the past half century.
Turner (157) recorded the killing of a moose in the vicinity of
Pastolik, near Saint Michaels, in the early winter of 1876. This
was said to be the first instance of moose occurrence, on the seacoast,
north of the Yukon River. In 1887 Nelson (101) remarked that
"[moose] lead a roaming life, and where they may be numerous one
season none may be found the next. The fur traders and Indians
claim that the moose has been found west of Fort Yukon only within
the last twenty-five or thirty years, and that only within the last
ten years have they been killed below Anvik and Mission, on the
Lower Yukon." Evidently the movement westward and northward,
into unburned country, is continuing at the present time. The
movements of the moose, as they extend their range, are most
perplexing.
In the treatise on the deer family by Roosevelt and others (131),
Andrew J. Stone prepared the section on moose. He offered an
interesting explanation for the increase in the moose population in
various areas, including the Kenai Peninsula, as follows:
They are now numerous in a very large territory in northwest
British Columbia, through the Cassiar Mountains, on Level
Mountain, and throughout the head waters of the Stickine
River, where thirty years ago they were unknown. They are now
abundant on the Kenai Peninsula, Alaska, and in other sections
of the North where at one time they did not exist. Acquisition
of territory by so wary aJJ. animal as the moose can only be
accounted for in one way. Many years ·ago the Indian tribes
occupying these sections were very numerous and inimical to
moose life, but, since the Indians have dwindled from thousands
to insignificant numbers, the moose finds comparatively un-
molested life. This I know to be the case on the Kenai and
in the country referred to in northwest British Columbia; and
there are many similar changes in conditions in other parts of
the North, notably in the Nahanna River country, north of the
Liard, where the entire tribe of Indians that once hunted the
country have died out, to the very great increase of moose.
Fires have, in numerous instances, resulted in the establishment of
rapidly growing, healthy forest stands of desired tree species. Silvi-
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 85
culturists in some regions have already learned how to use fire as a tool
to achieve their objectives. The gradual recognition among foresters
of the useful role that prescribed burning may play in forest manage-
ment has been accompanied by increased attention to protection
against accidental wildfires. The relationship between fire and game
management is in many respects analogous to that of fire and forest
management. In both fields fire may be used as a tool to favor
establishment of new vegetation, to influence or control species
composition, and for various other purposes. But neither in forest
management nor in wildlife management can uncontrolled fires be
justified. .
The solution of the problem is one that requires a strictly objective
approach. After the forester or the wildlife manager has ascertained
that fire is the most economical and effective means of attaining the
objectives of management, he should use it, and be prepared to accept
the same professional responsibility for results as a silviculturist
marking timber in a cultural operation or in a harvest cutting to
obtain natural reproduction. Leopold and Darling (82, p. 89) stated,
The wildfires of the past inadvertently improved many Alaskan
ranges for moose at an exorbitant cost in timber, watershed
cover, and caribou range. It is unthinkable that we can permit
unregulated burning to continue. The ambitious, but sadly
underfinanced fire control program of the Bureau of Land
Management (Division of Forestry) is the first positive step to
curb this destruction. Assuming that wildfire can be arrested in
the future, there remains the opportunity for the controlled use
of fire to improve selected winter ranges for moose where other
values may be considered subservient.
Caribou
The problem of fires and caribou is in a category wholly different
from that of fires and moose. Unlike the moose, which prefers
pioneer plant communities or at least vegetation representing early
stages of successional development, the barren ground caribou normally
lives in environments characterized by climax plant communities,
tundra, and forest-tundra transition.
Movements of caribou exhibit some of the same vagaries noted in the
movements of moose. In early times, for example, caribou were
known on the Kenai Peninsula (116, 79, 6), but are not now present.
Perhaps the last caribou observed in the region is that mentioned in
1912 by Shiras (144) who wrote "a good-sized stag was seen south of
Benjamin Creek by a party of surveyors last July [1911 ?]." Dufresne
(39) associated the disappearance of caribou from the Kenai country
with a forest fire that burned in the region in 1883. Other reasons for
their vanishing have been suggested by earlier writers.
Daniel G. Elliott (131, p. 279) observed "On ~he Kenai Peninsula
and surrounding districts head hunters, both white and red, have
nearly exterminated the species, and the increased means of transporta-
tion to and through their country, the large number of hunters, greatly
added to annually, and the improved firearms, would seem to foretell
the extinction in a brief period of this fine animal in the regions where
he is accessible."
86 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Allen (6), writing of the specimen of caribou that Andrew J. Stone
collected on September 24, 1900, quoted Stone as follows: "Cari-
bou . . . are already very scarce on the Kenai Peninsula, and will
doubtless soon be exterminated, the region being greatly frequented
by visiting sportsmen, while native hunters kill the moose and caribou
for their heads, disposing of them at good prices for shipment to
San Francisco." And Phillips (118) remarked that the caribou on the
Kenai Peninsula "vanished as rapidly as the buffalo when modern
rifles were sold to the natives by enterprising American traders."
As late as 1898 large bags of caribou were at least occasionally taken.
Thomas C. Dunn, President of the Murrina Alaska Gold Mining Co.,
in an account of a hunting expedition in 1898 of Harry·C. Lee (79),
stated that Lee found game abundant between the head of Chugachik
Bay (at the upper end of Kachemak Bay) and Tustumena Lake.
Lee killed three caribou.
It seems reasonably certain that the increased tempo of burning by
forest fires in Alaska since 1890 unfavorably affected caribou popula-
tions. Extensive forest fires, particularly in the lichen-rich forest-
tundra transition or woodland areas, have without doubt destroyed
large portions of the caribou range. Unlike moose browse, which in
favorable circumstances may develop in a few years following fires,
caribou range requires very many years for recovery after it has
been damaged by fire or by overgrazing.
Fruticose lichens of the Cladonia group, Cetraria spp., and Stereo-
caulon spp., together with certain beard lichens such as species of
Usnea and Alectoria growing on trees, form the principal winter food
of caribou and reindeer (40, 2, 84, 142, 113, 65). These lichens are
all readily killed by forest fixes and their recovery is extremely slow
as already noted in the section Herbaceous Plants. Aaltonen (2)
reported that even 20 to 30 years following fires the reindeer lichens in
Finland (chiefly Cladonia alpestris, C. rangiferina, C. sylvatica, and
C. uncialis) occurred only sparsely and attained heights of only a few
centimeters.
Lynge (84) noted that Cladonia alpestris and C. sylvatica grow very
slowly inN orway; he estimated that they would require a minimum of
25 to 30 years for full development, even under favorable conditions.
Lynge observed burned areas where, after 50 years or more, Cladonia
alpestris was scarcer and less well developed than in adjacent unburned
areas. In 1926 Palmer (108) stated,
It may take a burned-over lichen area as much as 25 years to
come back; or where so badly burned that the cover of humus
is destroyed, the changed site conditions may result in a recovered
stand of inferior species, or virtually in a permanent removal of
the lichens, so far as practical grazing use is concerned. In view
of the importance of the lichen areas for winter grazing, it is
vital to all reindeer men to guard against fires; and because of the
damage to game and fur animals and to tree growth, it is the con-
cern of everyone that fires be prevented and fire protection sought.
In 1945 Palmer and Rouse (11 0) expressed the view that "A de-
pleted lichen range under complete protection requires from 20 to 40
years for restoration to the original density and height growth." These
authors studied the recovery of tundra range after various treat-
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 87
ments intended to simulate grazing by reindeer. In an unpublished
report on burned woodland or timbered range, Palmer 6 stated, "A
full recovery in lichen composition comprising chiefly short growth
forms takes place in about 50 years, following destruction by fire.
For full return to the original cover of tall growth lichens it is indi-
cated that considerably more than 100 years will be required.."
Manning (89) believed. that complete recovery would require 30 years
in the country on the east side of Hudson Bay. Hustich (65) quoted.
the following estimates of the length of time required for r~covery
of reindeer lichens following fires: Itkonen, 40 to 50 years; Sarvas, 30
to 40 years. Hustich estirr:ated at least 40 years for recovery in
northeastern Canada.
Variations in estimates of the length of time required for redevelop-
ment of the lichen vegetation after fires are influenced by differences
of opinion of what constitutes recovery, by differences in the intensity
and extent of fires, and by differences in site and microclimate. A
conservative estimate of the usual length of time would appear to be
40 to 50 years, but in some instances it may be much more. A half
century, more or less, is a very long time for caribou range to be out
of production. Burned areas are avoided by caribou and, as Schier-
beck (136) has pointed out in Nova Scotia, the return of lichens to
such regions does not necessarily mean the return of caribou. Even
though the caribou are great travelers it seems reasonable to suppose
that they are adversely affected when their range is broken up into
small, often isolated, fragments by recurring fires. It also appears
probable that under these conditions excessive local overgrazing is
more common than on more extensive, continuous range.
The effects of severe fires on fur bearers may be summarized as
generally unfavorable. The effects of most fires on moose are generally
favorable, but caribou are adversely affected by all fires. Judgment
of whether forest fires are good or bad must usually be based on a
consideration of the sum total of values involved. These values are
tl.mber, wildlife, soil, water, and aesthetic or recreational values. In
management, priority may be given to one or a. combination of these
values, but only after due consideration of the others. The principle
of multiple use should be applied to the extent that it is consistent
with efficient resource management. Uncontrolled wildfires have no
place in either forest or wildlife management. The ultimate place of
prescribed burning in Alaska. cannot now be stated.. Neither the
forester nor the wildlife specialist in Alaska today has the requisite
knowledge to enable him to use prescribed burning on anything more
than a purely experimental basis. There is a great opportunity and
need for research on this problem. ·
EFFECT OF FIRE ON ECONOMIC DEVELOPMENT
The available natural resources will, in the long run, determine the ·
economic development of the Alaska interior. ,Without reasonably
complete information on these resources, prophecy on future develop-
ment becomes particularly hazardous.
6 pALMER, L. J. CARIBOU VERSUS FIRE IN INTERIOR ALASKA. (A STUDY OF
BURNED-OVER LICHEN RANGES.) U. S. Fish and Wildlife Service. 33 pp. 1941.
[Typewritten report.)
88 TECHNICAL :BULLETIN 1133, U. S. i>EPT. OF AGRICUV!'UREl
The nature and extent of Alaskan resources has long been a subject
of warm dispute. Ivan Petroff (115), writing in 1880, prefaced his
statement on the agricultural and pastoral resources of Alaska as
follows: "So much has been said upon this topic, of frantic declamation
on one hand, and indignant remonstrances on the other, that we
shall be very cautious in our presentation of what we believe or know
to be a fact." There is a tendency toward extreme views when
Alaskan resources are under consideration. At one pole are the
extreme pessimists who would "give it back to the Indians"; at the
other pole are the extreme optimists to whom the expression "land of
milk and honey" is a. fitting characterization of even the leanest of
regions. More temperate and more realistic would seem to be the
view that interior Alsska possesses important natural resources that
will one day be a firm basis for economic development but that these
resources are relatively modest and need to be carefully conserved
and used.
Among the resources that, wisely used, can support an economy
in perpetuity, the forests, with their great potential production of
cellulose, occupy an important place. They are of direct importance
as a source of forest products and of indirect importance as a habitat
for wildlife and as a feature of the tourist trade.
The threat of forest fires to the economic development of Alaska
has been recognized for years. The earliest and strongest condemna-
tion of fires did not come from professional conservationists but from
members of the Geological Survey. In 1911 Brooks (21) deplored
the widespread forest fires that he saw every summer as follows:
"It appears to the writer that at the present rate of consumption and
destruction by forest fires the timber of the Yukon-Tanana region
will not be sufficient for the placer-mining industry, let alone any
possible development when this stage has been passed."
In 1915, Ellsworth and Davenport (43) pointed out, "One of the
determining factors in the mining industry is the timber supply, not
only for fuel but for constructing flumes, mine supports, and buildings.
So far demands have been fairly met by the local growth, but large
inroads have been made by both legitimate use and by forest fires, and
the distance timber has to be transported is gradually increasing with
a corresponding increase in cost."
· In 1915 HenryS. Graves, then Chief Forester of the Forest Service,
visited the interior of Alaska. He was impressed with the appalling
losses resulting from fires and in 1916 made the following state-
ment (54):
The value of the interior forests should not be gauged by the size
and quality of the trees for lumber, or their place for possible
use in the general lumber markets of the Pacific coast. They
have rather an economic value as a local necessity-that can be
measured by contrasting the developments that will take place
with their aid, with the conditions that would exist without them
and will exist if they are destroyed. Nor can the economic
position of the forests be judged by their aggregate extent and
total volume of wood and timber. In a country of vast distances,
sparse population, high cost of labor, and meagre facilities for
transportation, it is the presence of forest supplies immediately
1: ' .
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 89
at hand that may make the development of industry and the estab-
lishment of homes in a given locality possible.
Drake (38), investigating the birch forests in the Susitna Valley,
noted the slight value which the people of the region placed on the
timber resources. In 1923 he observed,
The attitude that the local forests are of little value is detrimental
to the region's development, and public-spirited citizens should
endeavor to bring before the public mind the necessity of con-
serving the timber that will be needed for dwellings, farm build-
ings, bridges, telephone poles, mine props and that will attract
wood-using industries. . .. while no extensive market for this
timber has been found to date, one will eventually be secured
and steps should be taken to protect the forests until the time for
this exploitation is at hand.
What is needed is an awareness of the public that when uncontrolled
fires sweep through forest stands damage is done to the community
and Territory of which they are a part. What harms a country also
harms its citizens.
Interior Alaska simply does not have "timber to burn." Following
a severe fire, a minimum of 100 years and an average period of about
160 years must elapse before timber suitable for sawlogs again develops
on the burn. It is doubtful if the development of the Territory can
wait that long! Occasionally uncontrolled fires are condoned because
they burn in young timber not of commercial size or because they burn
in areas supporting growth that even the most optimistic forester
would admit had no present or future commercial prospect. Two
obvious facts may be pointed out in this connection. First, young
trees are always small and all large trees were once young. Second,
fires show no respect for values; seldom, if ever, does an extensive fire
burn solely in scrub growth. Some potentially valuable timber is
destroyed in every extensive burn.
The relation of uncontrolled fires to the wildlife resource has already
been discussed. It seems apparent that the widespread burning
that has occurred during the past half century or more has not resulted
in a land teeming with fur bearers and big game. It may be doubted
that more burning will produce such a result in the future.
Many thoughtful observers believe that the tourist trade, based
on recreational resources of all kinds, may well become one of interior
Alaska's most important sources of income. Here, again, unburned
landscapes are an asset and extensive burns are a liability. Few
persons intent on developing tourist or other recreational facilitiel'i
would choose a recently burned area. An extensive fire in the vicinity
of an established lodge would certainly not be a business asset.
The nuisance of forest fires extends far beyond the immediate
limits of the area burned. Smoke, spreading over wide areas, is a
source of annoyance to say the least; it may actu~lly disrupt air travel
and become a hazard to human life. MacDonald (85) gave an
eloquent description of the restrictions which smoke from forest fires
imposes on plane traveL For three days his plane was grounded at
Edmonton. In Alaska where plane travel is commonplace, smoke has
more than once prevented normal operations.
90 'l'ECHNICAL BUL:LETIN 1133, D. S. DEPT. OF AGRICULTURE
SUMMARY AND CONCLUSIONS
Of the land area of 366,435,000 acres in Alaska, about 60 percent
or approximately 219,861,000 acres, is in the interior. In this vast
area, tree growth is the dominant vegetation on most of the land below
an altitude of about 2,500 feet. Nearly 120 million acres bear sufficient
tree growth to warrant· designation as forest land.
The Alaska interior has a continental climate with great extremes
of temperature. Summer temperatures as high as 100° F. are known
and in the winter temperatures as low as -78° F. have been recorded.
Long days prevail during the short summer. Precipitation is light
north of the Alaska Range, amounting to about 10 to 15 inches
annually; south of the Alaska Range it averages around 20 inches.
The growing season is usually less than 90 days.
The forests of the interior present a mosaic of types resulting from
the .effects of forest fires and from variations in site. The latter are
associated with differences in water relations, permafrost conditions,
and soil aeration. Of the 120 million acres of forest land, some 40
million acres are believed to be commercial or potentially commercial.
Some 80 million acres of the interior bear sparse forests of open
woodland.
Sample plots indicate that at a rotation age of around 160 years
white spruce stands may average about 15,500 board-feet or 3,900
cubic feet per acre. Indications are that at 160 years of age, 80
percent of the trees would be 5 inches in diameter and larger and that
20 percent would exceed 12 inches in diameter; some of the trees
would then be 18 to 20 inches.
On the 40 million acres of commercial or potentially commercial
interior forest land it is estimated that there are some 32 billion cubic
feet or around 180 billion board-feet of timber. The forest resource is ·
so tremendous and so important to the future economy of Alaska
that it merits full consideration in the national program of forest
conservation.
Alaska has been subject during prehistoric and historic time to
extensive and repeated fires. Northern forests are highly flammable
when dry. The branches of dominantly coniferous trees frequently
persist nearly to the ground and often support beard lichens, which
have a tinderlike quality. The ground is commonly covered with
lichens, mosses, and small shrubs that readily carry fire. Man is the
principal cause of fires but lightning is also an important agent. An
average of at least a million acres of forest land has burned annually
for the last half century.
-As a result of :fires, the climax white spruce stands on moderately
well-drained sites have been replaced, over wide areas, by stands of
paper birch and quaking aspen. Both of these species are shorter
lived than white spruce, both have shorter pathological rotations, and
their timber cannot be stored on the stump as it can in white spruce
forests. Fires have had le&s effect in changing forest composition on
the forested lowland areas where black spruce represents a physio-
graphic climax. In the absence of repeated burns occurring at short
intervals, black spruce tends to perpetuate itself.
Revegetation of recently burned areas by forest trees is usually
prompt. Few, if any, areas can be found that are literally barren as a
ECOLOGICAL EFFECTS OF FOREST FIRES ~ ALASKA 91
·result of single fires even though the burning may be severe. Two
conditions are necessary for restocking of burned areas by forest
growth-supply of viable seed and exposed mineral soil. Both of
these conditions are fulfilled on most of the burned· areas and paper
birch, quaking aspen, or spruce-either pure or in mixture-are
developing. , Only on critically dry sites, such as steep slopes with
a southerly or westerly exposure, excessively drained alluvium, or
rocky slopes without mineral soil, has natural reforestation failed
in any important degree. In burned areas seedling reproduction tends
to be restricted to exposed mineral soil; charred forest floor material
represents a very poor seedbed, presumably because of the unstable
moisture supply and high surface temperatures. The outstanding
effects of fires are that vast amounts of existing timber are destroyed
and that the subclimax types (principally quaking aspen and paper
birch) are greatly increased at the expense of the white spruce type.
Paper birch is an early stage in forest succession, comparable to the
quaking aspen type. Paper birch produces large numbers of light,
easily disseminated seeds and forms even-aged stands. By the time
paper birch stands are about 80 years old, white spruce frequently
becomes prominent as an understory component. At 100 to 120 years
of age the paper birch declines and the spruce increases. Barring
major disturbances, such as fire, paper birch stands are gradually
converted to white spruce-paper birch forests. Fires tend to perpet-
uate the birch and reduce the representation of spruce. Following
fires, there is usually some sprouting of birch stumps, but the main
reason for the decline in spruce is that seed of that species is lacking or
in scanty supply.
The white spruce-paper birch type represents a stage of succession
comparable to the white spruce-quaking aspen type. It is more
advanced than either the paper birch or quaking aspen types. White
spruce-paper birch stands may develop immediately after fires or they
may result from gradual entry of white spruce into stands that were
initially pure paper birch. Spruce in mixture with birch suffers con-
siderably from crown friction. Even so, spruce gradually develops
into a dominant position. Defect becomes high in birch at about 100
years of age and the basal area of spruce is likely to exceed that of
birch in stands over 130 years of age. In the absence of disturbance,
white spruce-paper birch stands gradually change into essentially pure,
relatively open stands of white spruce. Fires tend to perpetuate the
birch and reduce the proportion of spruce. Here, however, the birch
is not favored as much nor is spruce repressed as greatly as in young
stands.
The quaking aspen type is a stage of forest succession analogous to
the paper birch type. Aspen regeneration after fires is often abundant,
from both root suckers and seed. . 'fhe stands tend to be even aged.
In the absence of fire or other disturbance, aspen occupies the land for
one generation only except on excessively dry southerly or westerly
slopes where it may persist indefinitely. White spruce, which may
have started with the aspen immediately after fl. fire, or which usually
enters the stand later, gradually dominates the site. White spruce in
aspen stands is subjected to less suppression and crown deformation
than in paper birch forests. Aspen is a short-lived species; decay is
92 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
common in 60-year-old stands. Fires in aspen stands perpetuate
aspen and destroy practically all the white spruce.
The white spruce-quaking aspen type is a stage of development
analogous to the white spruce-paper birch type. White spruce-
quaking aspen stands may become established immediately following
fires, but more characteristically they arise as a result of succession,
with the spruce gradually invading essentially pure aspen communities.
In the absence of fire, spruce gradually replaces the aspen, and rela-
tively open stands of spruce result .. Elimination of the aspen is rapid
in stands older than 60 years. Fire perpetuates aspen, largely because
of the capacity of the species to produce root suckers.
Balsam poplar forms essentially pure stands on recently deposited
alluvium. Many stands represent the first forest stage in a primary
successional series. Following fires, the species also invades upland
areas adjacent to large streams. Evidently balsam poplar may
occupy flood-plain areas indefinitely if they are subjected to periodic
overflow with deposition of silt and other alluvium. On relatively stable
sites, white spruce gradually assumes dominance, replacing the poplar.
Fires are not as common in the balsam poplar type as in other forest
communities but they are known to occur. Following fires, balsam
poplar reproduces by both root suckers and seeds. In many ways the
species behaves like quaking aspen.
The white spruce type is the climax forest on well-drained lands in
the interior. It is of widespread occurrence and is primarily responsible
for the vegetational aspect of the landscape. Young stands are often
essentially even aged but become uneven aged as they grow older.
High density is characteristic of white spruce forests established
immediately after fires. If the stands develop as a result of replace-
ment of aspen, paper birch, or balsam poplar, they are likely to be
relatively open. White spruce is probably longer lived than any other
tree in the Alaska interior. Ages of over 300 years have been deter-
mined. Diameters of occasional trees on especially favorable sites
may exceed 36 inches, and total heights may exceed 100 feet.
Single light surface fires in white spruce do not result in complete
destruction of the stands. Such fires create small openings where
seedlings of spruce, paper birch, and occasionally aspen and willows
develop. Single severe fires generally result in complete destruction
of existing stands and their replacement by subclimax communities,
chiefly quaking aspen and paper birch. Occasionally stands of essen-
tially pure white spruce develop following fires in the climax type. This
occurs most frequently when the burned areas are relatively small and
are surrounded by living trees of seed-bearing age. When the burns
are extensive the light-seeded birch and quaking aspen are more likely
to become established. Following fires, the fallen and standing snags
constitute an increased fire haza:.:d for 20 to 30 years.
As a result of repeated severe fires, areas formerly in white spruce
may become essentially treeless, supporting herbaceous or shrub
communities. Fireweed-grass and dwarf birch-willow may become so
firmly established that it is difficult for forest-tree seedlings to become
established. Natural reconversion of such lands to forest may require
100 to 200 years. Fires are most likely to result in replacement of
white spruce forest by relatively permanent treeless communities at the
upper altitudinal and latitudinal limits of fo.rest growt~
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 93
Black spruce is a physiographic climax on poorly drained situations,
in relatively fiat valley bottoms, on fiat to gently rolling land, and on
cold slopes having a northern exposure. It forms pure stands of usually
small, slow-growing trees. Permafrost is commonly encountered at
the shallow depth of 12 to 18 inches. In the absence of fire, black
spruce is a self-perpetuating type, reproducing by layering as well as
seed. Fires in black spruce are often intense, killing the vegetation
and consuming the forest floor. Even so, black spruce usually regener-
ates and another pure stand results. There is some evidence that
severe fires in black spruce, repeated at short intervals, may lead to
conversion to treeless communities such as sedge-rush-grass or low
shrub. Re-entry of black spruce may then be a very slow process.
The forest soils of interior Alaska are shallow in both a develop-
mental and a physiological sense. Excessive drainage may result in
deficient soil moisture in coarse-textured soils. On the other hand,
fine-textured soils may retain large amounts of water and become
poorly aerated and cold. Organic matter tends to remain unincor-
porated in the mineral soil, for the most part resting on it as a mantle.
Under old white spruce stands, and especially in the black spruce type,
the forest floor may become as thick as 12 inches.
The degree to which the forest floor material is removed by fires
varies with the intensity of the burn. It varies from slight charring
of the uppermost litter to complete consumption down to mineral soil.
In the recently burned areas examined, mineral soil was exposed over
only 30 to 40 percent of the surface, even after fires so severe that all
trees were killed. Practically none of the organic matter in the mineral
soil was destroyed.
Partial or complete removal of the forest floor by burning leads to
increased soil temperatures. In undisturbed condition, the moss and
lichen cover is an effective insulator in the summer period. It is dry
much of the time and effectively insulates the soil against the heat of
the sun. Removal of this cover results in higher surface temperatures
and a lower permafrost table. In general, the effects of fires on soil
temperature are ecologically favorable. Moisture relations on steep
southerly slopes are unfavorably affected by fires. In general, how-
ever, soil moisture relations do not appear to be greatly altered.
Soil texture and structure, so far as is known, are not changed by
burning. Runoff from steep slopes is increased as a result of forest
fires; the rate of infiltration apparently is reduced and the rate of
overland flow is increased. Erosion by wind and water do not appear
to be appreciably increased as a result of forest fires. The lack of
extensive water erosion seems to be explained by the low total amount
of precipitation, the normally low intensity of rainfall in individual
storms, the long period each year that the soils are frozen and snow
covered, and the rapidity of revegetation on burned lands.
Chemical changes in forest soils resulting from fires appear to be
ecologically favorable. Acidity is decreased, and exchangeable calcium
and potassium and readily available phosphorus 1are increased. Al-
though the total nitrogen capital of the site is reduced by fires that
consume the forest floor material, the amount of nitrogen available to
plants appears to be increased.
Burning has an effect similar to fertilization. The nutrient capital
in the forest floor, much of which may be regarded as a frozen asset,
94 TECHNICAL BULLETIN 11 3 3. U. S. DEPT. OF AGRICULTURE
is liberated in available ·form for use by the new plant growth. On the
majority of forest sites, the productivity of the mineral soil body does
not appear to be reduced by burning. From the standpoint of the soil
alone, fires may have a favorable effect on certain properties.
Effects of forest fires on the hydrologic regime in Alaska cannot be
stated with finality. Available evidence does point, however, to an
increase in the normally high ratio of runoff to precipitation and to
increased amplitude between high and low water stages. Watersheds
having steep slopes, from which the vegetation has been removed by
fire, have been reported to have very low minimum discharge rates and
flashy runoff.
The wildlife of interior Alaska is one of the important renewable
resources of the region. From it both the white population and natives
derive very considerable economic benefits. It is a resource which
has great attraction for hunters and for the even larger number of
tourists who merely wish to see and photograph wildlife in its natural
environment. Exceptions may occur, but in general .the effect of
uncontrolled forest fires on fur-bearing animals is unfavorable. This
view is in agreement with those expressed repeatedly by many wildlife
specialists.
The effect of uncontrolled forest fires on the moose population is
still not entirely clear. In certain areas following fires there has been
an increase of the moose population. It is only natural that this re-
lation be interpreted in terms of cause and effect., However, it is
doubtful that the relationship is a simple case of more browse, more
moose. There are extensive areas in the interior which have been
burned repeatedly and which support much .browse but few moose.
Moose in Alaska also have been moving westward and northward for
over 75 years and this movement has taken the animals into areas
where burning has not occurred. Thus the appearance and disap-
pearance or the presence of large or sparse populations of moose are
not to be explained simply and solely on the basis of fires or lack of
fires. The possibilities of prescribed burning are recognized.
The effects of fires on caribou are generally agreed to be harmful
or even disastrous. This animal normally lives in environments
characterized by climax communities, tundra and forest-tundra
transition. Fruticose lichens of the Cladonia group, together with
certain beard lichens (such as species of Usnea and Alectoria) growing
on trees, form the principal winter food of the caribou. These lichens
are highly flammable when dry and readily susceptible to destruction
by fire. Recovery is excessively slow. The length of time required
for full recovery varies with the extent and intensity of the fires and
site and microclimatic conditions, but an average of 40 to 50 years
appears to be a conservative estimate.
Uncontrolled fires, sweeping over vast areas of the interior nearly
every summer, place in jeopardy the future economic development of
that portion of Alaska. The area involved is vast but the resources
that can be used in perpetuity, even under wise management, are
relatively modest-certainly there is no excess to be wasted. Po-
tential production of cellulose on the better forest lands in the interior
is considerable. On the 40 million acres of commercial or potentially
commercial forest land, it is estimated that net annual growth is
about 960 million cubic feet. Following a severe fire, a minimum of
ECOLOGICAL EFFECTS OF FORES'l' FIRES IN ALASKA 95
100 years and an average period of perhaps 160 years must elapse
before spruce sawlogs can again be obtained from the burned area.
The important wildlife resource and the rapidly developing tourist
trade (whose potential can scarcely be judged at this time) are closely
related to the forest resource. What damages the forests of the
interior also damages these great economic assets.
The destiny of Alaska can be a great one only if her resources are
wisely used. Widespread destruction of forest and other vegetation
by fire, with all its harmful effects, cannot be judged wise use. The
citizens of the Territory have a serious responsibility to be good
stewards if the future Alaska is truly to become the "Great Land."
LITERATURE CITED
(1) ANONYMOUS.
1922. FOREST FIRES THE PLAGUE OF THE FUR TRADE. Jllus. Canad.
Forestry Mag. 18 (2) : 603-604.
(2) AALTONEN, v. T.
1919. [UBER DIE NATURLICHE VERJUNGUNG DER HEIDEWALDER IM FIN-
NISCHEN LAPPLAND, 1.] KANGASMETSIEN LUONNOLLISESTA UUDIS-
TUMISESTA SUOMEN LAPISSA, I. Inst. Quaest. Forest. Finland,
Commun. 1: 1-319, 1-56. [German summary, pp. 1-56.]
(3) ABERCROMBIE, w. R.
(4)
1900: ALASKA.-1898. COPPER RIVER EXPLORING EXPEDITION. In Com-
pilation of Narratives of Explorations in Alaska. U. S. Senate
(5.6th Cong., 1st Sess.) Rpt. 11 (1023): 561-591, ill us.
1900. REPORT OF A SUPPLEMENTARY EXPEDITION INTO THE COPPER RIVER
VALLEY, ALASKA, 1884. In Compilation of Narratives of Explora-
tions in Alaska. U. S. Senate (56th Cong., 1st Sess.) Rpt. 11
(1023): 381-408.
(5) ALLEN, HENRY T.
1900. REPORT OF A MILITARY RECONNAISSANCE IN ALASKA MADE IN 18!!5.
In Compilation of Narratives of Explorations in Alaska. U. S.
Senate (56th Cong., 1st Sess.) Rpt. 11 (1023): 409-488, illus.
(6) ALLEN, J. A.
1901. DESCRIPTION OF A NEW CARIBOU FROM KENAI PENINSULA, ALASKA.
Amer. Mus. Nat. Hist. Bul. 14: 143-148.
(7) ALT;ER, AMOS J.
1950,. ('i;)~~~~~~~~Y IN ALASKA. Amer. Waterworks Assoc. Jour. 42
(8) AUER, VAINO.
1928. [PRESENT PEAT BOGS IN SOUTHEASTERN CANADA.] NYKYISISTA
KAAKKOIS-KANADAN soisTA. Inst. Quaest. Forest. Finland,
Cominun. 13: 1-55.
(9) BARNARD, E. C.
1900. FORTYMILE QUADRANGLE, ALASKA: In Classification of Lands, by
Henry Gannett and others. U. S. Geol. Survey (1899-1900)
Ann. Rpt. 21 (Pt. 5): 569-601.
(10)
(11)
(12)
(13)
BEDELL, G. H. D.
1948. WHITE SPRUCE REPRODUCTION IN MANITOBA. Canada Forest
Serv., Silvicultural Res. Note 87, 16 pp.
BELL, R.
1889. FOREST FIRES IN NORTHERN CANADA. Reprinted from the Report
of the American Forestry Congress, Atlanta Meeting, 1888, 7 pp.
BENNETT, H. H. I
· 1914. SOIL RECONNAISSANCE IN ALASKA, WITH{" AN ESTIMATE OF THE
AGRICULTURAL POSSIBILITIES. U. S. Dept. Agr., Bur. Soils Field
Operations Rpt. 16, 202 pp.
1916. REPORT ON A RECONNAISSANCE OF THE SOILS, AGRICULTURE, AND
OTHER RESOURCES OF THE KENAI PENINSULA REGION OF ALASKA.
U. S. Dept. Agr., Bur. Soils Field Operations Rpt. 18, 142 pp._
349169-56-7
96 TECHNICAL BULLETIN 1133, U. S. DEP'l'. OF AGRICULTURE
(14) BENNINGHOFF, w. S.
1950. USE OF AERIAL PHOTOGRAPHS IN MAPPING VEGETATION AND SUR-
FICIAL GEOLOGY IN SUBARCTIC REGIONS. Photogrammetric
Engin. 16: 428-429.
(15) BENSON, MARGARET, and BLACKWELL, ELIZABETH.
1926. OBSERVATIONS ON A LUMBERED AREA IN SURREY FROM 1917 TO
1925. Jour. Ecol. 1-l: 120-137.
(16) BoRG, L. E. T. .
1936. [DIE 1913-1930 AUSGEFUHRTEN SCHNEESAATEN IM REVIER TUO-
MARNIEMI.] HANKIKYLVOT TUOMARNIEMEN HOITOALUEESSA VV.
1913-1930. Silva Fenn. 38: 1-136. [German summary, pp. 125-
136.]
{17) Bouyoucos, G. J.
1936. DIRECTIONS FOR MAKING MECHANICAL ANALYSES OF SOILS BY THE
HYDROMETER METHOD. Soil Science 42: 225-229.
(18) BRABANT, ANGUS.
1922. THE FIRE FIEND'S THREAT TO THE FUR TRADE. FINEST PELTS
COME FROM THE MOST DENSELY WOODED DISTRICTS-FOREST FIRES
DESTROY SHELTER, SHADE AND FOOD. Illus. Canad. Forestry
Mag. 18 (12) : 1204-1205.
(19) BROOKS, A. H.
(20)
(21)
1900. A RECONNAISSANCE IN THE TANANA AND WHITE RIVER BASINS,
ALASKA, IN 1898. U. S. Geol. Survey Ann. Rpt. (1898-99) 20
(Pt. 7) : 425-509.
1906. THE GEOGRAPHY AND GEOLOGY OF ALASKA, A SUMMARY OF EXISTING
KNOWLEDGE. U. S. Geol. Survey Prof. Paper 45, 327 pp.
1911. THE MOUNT MCKINLEY REGION, ALASKA. U. S. Geol. Survey
Prof. Paper 70, 234 pp.
(22) BuHLER, ANToN.
1918. DER WALDBAU NACH WISSENSCHAFTLICHER FORSCHUNG UND
PRAKTISCHER ERFAHRUNG. Bd. 1. 662 pp. Stuttgart.
(23) CAIRNES, D. D.
1912. GEOLOGY OF A PORTION OF THE YUKON-ALASKA BOUNDARY BE-
TWEEN PORCUPINE AND YUKON RIVERS. Canad. Geol. Survey
Ann. Rpt. 1911: 17-33.
(24) CAMP, RAYMOND R.
1948. THE HUNTER's ENCYCLOPEDIA. 1152 pp. New York.
(25) CANADIAN BUREAU OF NORTHWEST TERRITORIES AND YUKON AFFAIRS.
1944. THE NORTHWEST TERRITORIES (ADMINISTRATION, RESOURCES,
DEVELOPMENT). Canad. Bur. Northwest Territories and Yukon
Affairs, Ottawa. 59 pp. [Processed.]
(26) CAPPS, STEPHEN R.
1919. MINERAL RESOURCES OF THE WESTERN TALKEETNA MOUNTAIN5.
In Mineral Resources of Alaska, Report on Progress of Investiga-
tions in 1917. U.S. Geol. Survey Bul. 692: 187-205.
(27) CAPPS, s. R.
1929. THE MOUNT SPURR REGION, ALASKA. U. S. Geol. Survey Bul.
81Q-C: 141-172.
(28)
(29)
(30)
(31)
(32)
1931. GLACIATION IN ALASKA. U. S. Geol. Survey Prof. Paper 17Q-A,
8 pp.
1935.. THE sou·rHERN ALASKA RANGE. U. S. Geol. Survey Bul. 862,
101 pp.
---and TucK, RALPH.
1935. THE WILLOW CREEK-KASHWITNA DISTRICT, ALASKA. U. S. Geol.
Survey Bul. 864-B: 95-113.
CHAMBERS, ERNEST J.
1908. THE GREAT MACKENZIE BASIN. Reports of the Select Committee
of the Senate, Sessions 1887 and 1888. 80 pp. Ottawa.
CHATELAIN, EDWARD P.
1950. BEAR-MOOSE RELATIONSHIPS ON THE KENAI PENINSULA. North
Amer. Wildlife Conf. Trans. 15: 224-234.
f .
r
I
~
I
' I
I
" I
mcoLOGICAL EFFECTS OF FOREST FIRES ~ ALASKA 97
(33) CHICAGO AcADEMY OF SciENcEs.
1867'-"69. BIOGRAPHY OF ROBERT KENNICOTT. Chicago ·Acad. Sci.
Trans. 1: 133-226.
(34) CoLLIER, ARTHUR J.
1901. NOTES ON THE VEGETATION. In Reconnaissances in the Cape
Nome and Norton Bay Regions, Alaska, in 1900, by Alfred H.
Brooks, George B. Richardson, Arthur J. Collier, and Walter C.
Mendenhall. pp. 164-174. U.S. Geol. Survey, Washington.
(35) CowAN, I. MeT., HoAR, W. S., and HATTER, J.
1950. THE EFFECT OF FOREST SUCCESSION UPON THE QUANTITY AND UPON
THE NUTRITIVE VALUES OF WOODY PLANTS USED AS FOOD BY
MOOSE. Canad. Jour. Res., D, 28: 249-271.
(36) DAVIES, w. H. A.
1843. NOTES ON ESQUIMAUX BAY AND THE SURROUNDING COUNTRY.
Quebec Literary and Hist. Soc. Trans. 4: 7()-,-94.
· (37) DoRoscHIN, P. ·
1867. EINIGE BEOBACHTUNGEN UND BEMERKUNGEN UBER DAS GOLD-
VORKOMMEN IN DEN BESITZUNGEN DER RUSSISCH-AMERIKANISCHEN
COMPAGNIE. Arch. f. Wiss. Kunde von Russland 25: 229-237.
(38) DRAKE, GEORGE L.
1923. BIRCH-SPRUCE FORESTS OF SOUTHWESTERN ALASKA. Timberman
25 (2): 51-53.
(39) DUFRESNE, FRANK.
1946. ALASKA'S ANIMALS AND FISHES. 297 pp. New York.
(40) DuGMORE, A. A. RADCLYFFE.
1913. THE ROMANCE OF THE NEWFOUNDLAND CARIBOU, AN INTIMATE
ACCOUNT OF THE LIFE OF THE REINDEER OF NORTH AMERICA.
191 pp. London.
(41) DYMOND, J. R.
1934. PROBLEMS IN THE CONSERVATION OF GAME AND FUR-BEARING
MAMMALS. Pacific Sci. Congress, Canada, Proc. (1933) 5:
4077-4078.
(42) ELDRIDGE, GEORGE H.
1900. A RECONNAISSANCE IN THE SUSHITNA BASIN AND ADJACENT TERRI-.
TORY, ALASKA, IN 1898. U. S. Geol. Survey Ann. Rpt. (1898-99)
20 (Pt. 7): 1-29.
(43) ELLSWORTH, C. E., and DAVENPORT, R. W.
1915. SURFACE WATER SUPPLY OF THE YUKON-TANANA REGION, ALASKA.
U. S. Geol. Survey, Water-Supply Paper 342, 343 pp.
(44) ENEROTH, OTTO.
1928 .. (CONTRIBUTION TO THE KNOWLEDGE WE HAVE OF THE EFFECT ON
THE SOIL FROM BURNING OF CLEARINGS.) BIDRAG TILL KAN-
NEDOMEN OM HYGGESBRANNINGENS INVERKAN PA MARKEN.
Svenska Skogsvardsfor. Tidskr. 26: 685.,-758. U. S. Forest
Service Translation No. 61.
(45) GABRIELSON, IRA N.
, (46)
1928. FOREST FIRE AND WILDLIFE. Four L Lumber News 10 (13): 32.
1941. WILDLIFE CONSERVATION. 250 pp. New York.
(47) GARMAN, E. H.
1929. NATURAL REPRODUCTION FOLLOWING FIRES IN CENTRAL BRITISH
COLUMBIA. Forestry Chron. 5: 28-44.
(48) GILMORE, J. D.
1925. FIRST STEPS IN FOREST MANAGEMENT. Jour. Forestry 23:
617-625.
(49) GLAVE, E. J.
(50)
(51)
(52)
1892. PIONEER PACKHORSES IN ALASKA. Century Mag. (n. S. 22)
GLENN,
1900.
GRAFF,
1935.
1936.
44: 671-682, 869-881.
E. F.
ALASKA.-TANA_NA RIVER EXPLORING EfCPEDITION. In Compila-
tion of Narratives of Explorations in J\laska. U.S. Senate (56th
Cong., 1st Sess.} Rpt. 11 (1023): 627-648.
PAUL w.
PLANT INVASION FOLLOWING FIRES. Torreya 35: 137~141.
INVASION BY MARCHANTIA POLYMORPHA FOLLOWING FORES'l'
FIRES. Torrey Bot. Club Bul. 63: 67-74.
98 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
(53) GRAVES, H. s.
1916. THE FORESTS OF ALASKA. Timberman 17 (6): 33-37.
(54)
(55)
(56)
(57)
. (58)
(59)
(60)
(61)
(62)
(63)
(64)
(65)
1916. THE FORESTS OF ALASKA. Amer. Forests 22: 24-37.
GULISASHVILI, V. Z., and STRATONOVITCH, A. I.
1935. (PHYSICAL CHARACTERISTICS OF FOREST SOILS AND THE CHANGES
THEY UNDERGO UNDER THE INFLUENCE OF FOREST MANAGEMENT.]
Fil!'ICHESKIE SVOISTVA LESNYKH POCHV I IKH IZMENENIIA POD
VLIIANIEM LESOKHOZIAISTVENNYKH MEROPRIIATII. 148 pp.,
illus. Goslestekhizdat. Leningrad. U.S. Forest Service Trans-
lation No. 254.
GuTHRIE, JoHN D.
1922. ALASKA'S INTERIOR FORESTS. Jour. Forestry 20: 363-373.
HASKELL, WILLIAM B.
1898. TWO YEARS IN THE KLONDIKE AND ALASKAN GOLDFIELDS. 558 pp.
Hartford, Conn. ,
HEIKINHEIMO, 0LLI.
1915. (DER EINFLUSS DER BRANDWIRTSCHAFT AUF DIE WALDER FINN-
LANDS.] KASKIVILJELYKSEN VAIKUTUS SUOMEN METSIIN. Acta
Forest. Fenn. 4: 1-264, 1-149, 1-59. [German summary,
pp. 1-59.]
HESSELMAN' HENRIK.
1917. (ON THE EFFECT OF OUR REGENERATION MEASURES ON THE FORMA-
TION OF SALTPETER IN THE GROUND AND ITS IMPORTANCE IN THE
REGENERATION OF CONIFEROUS FORESTS.] OM VARA SKOGSFO-
RYNGRINGSATGARDERS INVERKAN PA SALPETERBILDNINGEN I
MARKEN OCH DESS BETYDELSE FOR BARRSKOGENS FORYNGRING.
[Sweden] Meddel. f. Statens Skogsforsoksanst. 13-14: 923-1076.
[English summary, pp. xci-cxxvi.]
1937. [UBER DIE ABHANGIGKEIT DER HUMUSDECKE VON ALTER UND
ZUSAMMENSETZUNG DER BESTANDE IM NORDISCHEN FICHTENW ALD
VON BLAUBEERREICHEM VACCINIUM-TYP UND UBER DIE EIN-
WIRKUNG DER HUMUSDECKE AUF DIE VERJUNGUNG UND WACHSTUM
DES WALDES.] OM HUMUSTACKETS BEROENDE AV BESTANDETS
ALDER OCH SAMMANSATTNING I DEN NORDISKA GRANSKOGEN AV
BLABARSRIK VACCINIUM-TYP OCH DESS INVERKAN PA SKOGENS
FORYNGRING OCH TILLVAXT. [Sweden] Meddel. f. Statens Skog-
sforsoksanst. 30: 529-716. [German summary, pp. 669-715.]
1939. [WEITERE STUDIEN UBER DIE BEZIEHUNG ZWISCHEN DER SAMEN-
PRODUKTION DER KIEFER UND FICHTE UND DER BESAMUNG DER
KAHLHIEBE.] FORTSATTE STUDIER OVER TALLENS OCH GRANENS
FROSPRIDNING SAMT KALHYGGETS BESANING. (Sweden] Meddel.
f. Ste.tens Skogsfiirsiikse.nst. 31: 1-64. [German summary, pp.
58-64.]
HOLMAN, H. L.
1927. NATURAL REGENERATION OF SPRUCE IN ALBERTA. Forestry Chron.
3 (3): 4-6. [Processed.]
---AND PARKER, H. A.
1940. SPRUCE REGENERATION. The Prairie Provinces-V. H. Phelps.
Forestry Chron. 16: 79-83.
H USTICH, lLMARI.
1949. ON THE FOREST GEOGRAPHY OF THE LABRADOR PENINSULA. A
PRELIMINARY SYNTHESIS. Acta Geog. 10 (2)-: F-63.
1951. THE LICHEN WOODLANDS IN LABRADOR AND THEIR IMPORTANCE AS
WINTER PASTURES FOR DOMESTICATED REINDEER. Acta Geog.
12 (1): 1-48.
(66) IsAAc, L. A., and HoPKINs, H. G.
1937. THE FOREST SOIL OF THE DOUGLAS FIR REGION, AND CHANGES
WROUGHT UPON IT BY LOGGING AND SLASH BURNING. Ecology 18:
264-279.
(67) KARR, H. w. SETON.
1887. SHORES AND ALPS OF ALASKA. 248 pp. Chicago.
(68)
(69)
(70)
(71)
(72)
(73)
(74)
(75)
(76)
(77)
(78)
(79)
(80)
(81)
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 99
KELLOGG, CHARLES E., and NYGARD, I. J.
1949. SOILS OF ALASKA. In Report on Exploratory Investigations of
Agricultural Problems of Alaska. U. S. Dept. Agr. Misc. Pub.
700: 25-86.
KELLOGG, R. S.
1910. THE FORESTS OF ALASKA. U.S. Dept. Agr., Forest Surv. Bul. 81,
24 pp., illus. ·
KINCER, J. B.
1941. SUPPLEMENTARY CLIMATIC NOTES FOR ALASKA. U. S. Dept. Agr.
Yeerbook (Climate and Man) 1941: 1211-1215.
KITTREDGE, JoSEPH, JR., and GEVORKIANTZ, S. R.
1929. FOREST POSSIBILITIES OF ASPEN LANDS IN 'l"HE LAKE STATES.
Minn. Agr. Expt. Sta. Tech. Bul. 60, 84 pp.
KIVEKAS, JORMA.
1939. ["UBER DEN EINFLUSS DER BRANDKULTUR AUF EINIGE EIGEN-
SCHAFTEN DES BODENS.] KASKIVILJELYKSEN VAIKUTUS ERAISIIN
MAAN OMINAISUUKSIIN. Inst. Forest. Fenniae Commun. 27:
1-44. [German summary, pp. 43-44.]
KOHH, ELMAR.
1936. [BEOBACHTUNGEN UBER REIFEN UND FALLZEIT DER SAMEN IM
LEHR-UND VERSUCHS-FORSTAMT V. J. I93D-1935]. VAATLUSI
SEEMNETE VALliHMISE JA VARISEMISE KOHTA ULIKOOLI OPPE-
JA KATSEMETSKONNAS 193D-I935 A. Tartu Ulikooli Metsaosa-
konna Toimetused· No. 27, 124 pp .. [German summary, pp.
108-123.
KuJALA, VILJO.
. 1926. UNTERSUCHUNGEN UBER DEN EINFLUSS VON WALDBRANDEN AUF DIE
W ALDVEGETATION IN NORDFINNLAND. SUOMENKIELINEN _SELOS-
TUS: TUTKIMUKSIA KULOJEN VAIKUTUKSESTA METSAKASVILLISU-
UTEEN POHJOIS-SUOMESSA. Inst. Quaest. Forest. Finland, Cgm-
mun. 10: 1-41, illus.
LAGUNA, FREDERICA DE.
1934. THE ARCHAEOLOGY OF COOK INLET, ALASKA. Univ. of Penn. Press.
263 pp.
LEARNARD, H. G.
1900. ALASKA.-1898. A TRIP FROM PORTAGE BAY TO TURNAGAIN ARM
AND UP THE susHITNA. In Compilation of Narratives of Explo-
rations in Alaska. U. S. Senate (56th Cong., 1st Sess.) Rpt. 11
(1023): 648-677.
LEBARRON, RussELL K.
1945. ADJUSTMENT OF BLACK SPRUCE ROOT SYSTEMS TO INCREASING
DEPTH OF PEAT. Ecology 26: 309-311.
1948. SILVICULTURAL MANAGEMENT OF BLACK SPRUCE IN MINNESOTA.
U. S. Dept. Agr. Cir. 791, 60 pp., illus.
[LEE, HARRY C.]
1898. AN ALASKA GAME COUNTRY. Forest and Stream 51 (20); 386.
LEOPOLD, ALDO.
1923. WILD FOLLOWERS OF THE FOREST. THE EFFECT OF FOREST FIRES
ON GAME AND FISH-THE RELATION OF FORESTS TO GAME CONSERV A-
TION. Amer. Forestry 29 (357): 515-519, 568.
1933. GAME MANAGEMENT. 481 pp. New York.
(82) ·LEOPOLD, A. STARKER, and DARLING, F. FRASER.
1953. WILDLIFE IN ALASKA. 129 pp. New York.
(83) Low, A. P.
. (84)
(85)
1896. REPORT ON EXPLORATIONS IN THE LABRADOR PENINSULA ALONG
THE EAST MAIN, KOKSOAK, HAMILTON, MANICUAGAN AND PORTIONS
OF OTHER RIVERS IN 1892--93-94-95. Ca:qada. Geol. Survey Ann.
Rpt. (n. s.) 8, 387 pp .
LYNGE, BERNT.
1921. STUDIES ON THE LICHEN FLORA OF NORWAY. SKRIFTER UTGIT AV
VIDENSKAPSSELSKAPET I KRISTIANIA, -1921. J. Matematisk-
. Naturvidenl,lkabelig Klasse Bd. 1, no. 7, 252 pp.
MAcDoNALD, MALCOLM. .
1943. DOWN NORTH, A VIEW OF NORTHWEST CANADA. 274 pp. New
York.
100
(86)
(87)
(88)
(89)
(90)
(91)
'(92)
(93)
(94)
(95)
(96)
TECHNICAL BULLETIN 11 3 3, U. S. DEPT. OF AGRICULTURE
McKENNA, J. A. J.
1908. THE HUDSON BAY ROUTE. A COMPILATION OF FACTS WITH CON-
CLUSIONS. 54 pp. OttewP •.
MACKENZIE, ALEXANDER.
1801. VOYAGES FROM MONTREAL, ON THE RIVER ST. LAURENCE, THROUGH
THE CONTINENT OF NORTH AMERICA, TO THE FROZEN AND PACIFIC
OCEANS; IN THE YEARS I789 AND I793. WITH A PRELIMINARY
ACCOUNT OF THE RISE, PROGRESS, AND PRESENT STATE OF THE FUR
TRADE OF THAT COUNTRY. 412 pp. London.
McLENEGAN, S. B.
1887. EXPLORATION OF THE NOATAK RIVER, ALASKA. Jn Report of the
Cruise of the Revenue Marine Steamer Corwin in the Arctic
Ocean in the Year 1885, by M. A. Healy. · U. S. Exec. (49th
Cong., 1st Sess.) Doc. 153: 53-80.
MANNING, T. H.
1946. BIRD AND MAMMAL NOTES FROM THE EAST SIDE OF HUDSON BAY.
Cenad. Field Nat. 60 (4): 71.
MARSHALL, RoBERT.
1933. ARCTIC VILLAGE. 399 pp. New York.
MARTIN, ALEXANDER C., ZrM, HERBERT S., and NELsoN, ARNOLD L.
1951. AMERICAN WILDLIFE AND PLANTS. 500 pp. New York.
MELECHOW, J. S.
1934. ZUR FRAGE DER NATURLICHEN VERJUNGUNG DER FICHTE AUF
BRANDFLACHEN. Forstwiss. Centbl. 56:47-61.
MERTlE, J. B., JR.
1929. THE CHANDALAR-SHEENJEK DISTRICT, ALASKA. U.S. Geol. Survey
Bul. 810-B: 87-139.
1932. THE TATONDUK-NATION DISTRICT, ALASKA. U. "8. Geol. Survey
Bul. 836-E: 347-443.
1937. THE YUKON-TANANA REGION, ALASKA. U. S. Geol. Survey Bul.
872, 276 pp.
MIDDENDORFF, A. TH. v.
1867. REISE IN DEN AUSSERSTEN NORDEN UND OSTEN SIBIRIENS. UBER-
SICHT DER NATUR NORD-UND OST-SIBIRIENS. EINLEITUNG, GEO-
GRAPHIE, HYDROGRAPHIE, OROGRAPHIE, GEOGNOSIE, KLIMA UND
GEWACHSE. Vol. 4, Pt. I. 783 pp. Kaiserlichen Akademie der
Wissenschaften. St. Petersburg.
(97) MILLAR, J. B.
1940. SPRUCE REGENERATION. ONTARIO. Forestry Chron. 16: 21-29.
(98) MoFFIT, F. H.
1935. GEOLOGY OF THE TONSINA DISTRICT, ALASKA. U. S. Geol. Survey
Bul. 866, 38 pp.
(99) ---and STONE, RALPH W.
1906. MINERAL RESOURCES OF KENAI PENINSULA, ALASKA. U. S. Geol.
Survey "Bul. 277, 80 pp., illus.
(100) MULLER, SIEMON W.
1947. PERMAFROST OR PERMANENTLY FROZEN GROUND AND RELATED
ENGINEERING PROBLEMS. 231 pp. Ann Arbor, Mich.
(101) NELSON, EDWARD w.
1887. REPORT UPON NATURAL HISTORY COLLECTIONS MADE IN ALASKA
BETWEEN THE YEARS 1877 AND 1881. U. S. Army, Signal Service
Arctic Series 3, 337 pp.
(102) NIEDIECK, PAuL.
1909. CRUISES IN THE BERING SEA, BEING RECORDS OF FURTHER SPORT
AND TRAVEL. (Translated from the original German by R. A.
Ploetz.) 252 pp. London.
(103) NuTTONSON, M. Y.
1950. AGRICULTURAL CLIMATOLOGY OF SIBERIA, NATURAL BELTS, AND
AGRO-CLIMATIC ANALOGUES IN NORTH AMERICA. Amer. lnst.
Crop Ecology Study 13, 64 pp.
(104) OsGooD, CoRNELIUS.
1937. THE ETHNOGRAPHY OF THE TANAINA. Yale Univ. Anthrop?logy
Pub. 16, 229 pp.
(105)
(106)
(107)
(108)
(109)
(110)
(111)
(112)
(113)
(114)
(115)
(116)
(117)
t (118)
I
l (119)
f
(120)
I (121)
I
(122)
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 101
OsGooD, WILFJtED H.
1901. NATURAL HISTORY OF THE QUEEN. CHARLOTTE ISLANDS, BRITISH
COLUMBIA; NATURAL HISTORY OF THE COOK INLET REGION, ALASKA.
U.S. Dept. Agr., Div. Biological Survey, North American Fauna
21, 87 pp.
1908. THE GAME RESOURCES OF ALASKA. U. S. Dept. Agr. Yearbook
1907: 469-482.
1909. BIOLOGICAL INVESTIGATIONS IN ALASKA AND YUKON TERRITORY.
U. S. Dept. Agr., Bur. Biological Survey, North American
Fauna 30, 96 pp.
PALMER, LAWRENCE J.
1926. PROGRESS OF REINDEER GRAZING INVESTIGATIONS IN ALASKA.
U. S. Dept. Agr. Dept. Bul. 1423, 37 pp.
1933. RANGE RECONNAISSANCE KENAI PENINSULA MOOSE AREA. 8 pp.
[Processed.]
---AND RousE, CHARLES H.
1945. STUDY OF THE ALASKA TUNDRA WITH REFERENCE TO ITS REACTIONS
TO REINDEER AND OTHER GRAZING. U. S. Fish and Wildlife Serv.
Res. Rpt. 10, 48 pp.
PEARSON, H. BRIAN.
1900. ALASKA.-1899. THE UPPER TANANA BASIN. In Compilation of
Narratives of Explorations in Alaska. U.S. Sene.te (56th Cong.,
1st Sess.) Rpt. 11 (1023): 814-816.
PEECH, M., ALEXANDER, L. T., DEAN, L.A., and REED, J. F.
1947. METHODS OF SOIL ANALYSIS FOR SOIL-FERTILITY INVESTIGATIONS.
U. S. Dept. Agr. Cir. 757, 25 pp.
PEREZ-LLANO, GEORGE A.
1944. LICHENS-THEIR BIOLOGICAL AND ECONOMIC SIGNIFICANCE. Bot.
Rev. 10 (1): 1-65. -
PERSSON, HERMAN.
1949.. STUDIES IN THE BRYOPHYTE FLORA OF ALASKA-YUKON. Svensk
Bot. Tidskr. 43: 491-533.
PETROFF, IVAN.
1880. POPULATION AND RESOURCES OF ALASKA. U.S. Exec. (46th Cong.,
3d Sess.) Doc. 40, 86 pp.
1884. REPORT ON THE POPULATION, INDUSTRIES, AND RESOURCES OF
ALASKA. U. S. Dept. of the Interior, Census Office. Tenth
Census of the United States, 1880. Vol. 8. 189 pp.
PETTERSSON, BROR.
1931. NOTES ON THE FIRST STAGES OF FLORA ON BURNT GROUND. Soc.
pro Fauna et Flora Fenn. Memoranda 7 (2): 119-139.
PHILLIPS, JOHN 0.
1925. CONSERVATION OF OUR MAMMALS AND BIRDS. In Hunting and
Conservation, the Book of the Boone and Crockett Club. pp.
29-65. New Haven.
POHLE, RICHARD.
1901. PFLAN'ZENGE.OGRAPHISCHE STUDIEN UBER DIE HALBINSEL KANIN
UND DAS ANGRENZENDE WALDGEBIET .. Inaugural Dissertation
(Rostock). 112 pp.
1917. WALD-UND BAUMGRENZE IN NORD-RUSSLAND. [Berlin] Gesell.
f. Erdk. Ztschr. pp. 205-229.
PRASOLOV, L. I.
1932. THE CLIMATE AND SOILS OF NORTHERN EURASIA AS CONDITIONS OF
coLONIZATION. In Pioneer Settlement. Cooperative studies by
twenty-six authors. Amer. Geog. Soc. SJPeC. Pub. 14: 240-260.
PREBLE, EDwARD A. i ·
1908. A BIOLOGICAL INVESTIGATION_ OF THE ATliABASKA-MACKENZIE
· REGION. U. S. Bur. Bioi. Survey, North American Fauna 27,
574 pp.
102 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICUL'.r"URE
(123) PuLLING, HowARD E.
1918. ROOT HABIT AND PLANT DISTRIBUTION IN THE FAR NORTH. Plant
World 21 (9): 223-233.
(124) RAUP, HUGH M.
(125)
1945. FORESTS AND GARDENS ALONG THE ALASKA HIGHWAY. Geog. Rev.
35 (1): 22-48.
1947. THE BOTANY OF SOUTHWESTERN MACKENZIE. Sargentia 6: 1-275.
(126) ---and DENNY, CHARLES S.
1950. PHOTO INTERPRETATION OF THE TERRAIN ALONG THE SOUTHERN
PART OF THE ALASKA HIGHWAY. U. S. Geol. Survey Bul. 963-D:
95-135.
(127) REIM, PAUL.
1930. (DIE VERMEHRUNGSBIOLOGIE DER ASPE.] HAAVA PALJUNEMIS-
BIOLOOGIA. Tartu tilikooli Metsaosakonna Toimetused No.
16, 188 pp. [German summary, pp. i-xvi.]
(128) RENVALL, AuGusT.
(129)
(130)
(131)
1912. DIE PERIODISCHEN ERSCHEINUNGEN DER REPRODUKTION DER
KIEFER AN DER POLAREN W ALDGRENZE.
1, 154 pp.
RICE, JoHN F.
Acta Forest. Fenn.
1900. ALASKA.-1899. FROM VALDEZ TO EAGLE CITY. In Compilation
of Narratives of Explorations in Alaska. U. S. Senate (56th
Cong., 1st Sess.) Rpt. 11 (1023): 784-789.
RoHN, OscAR.
1900. A RECONNAISSANCE OF THE CHITINA RIVl!'R AND THE SKOLAI
MOUNTAINS, ALASKA. U. S. Geol. Survey Ann. Rpt. 21 (2):
393-440.
RoosEVELT, THEODORE, VAN DYKE, T. S., ELLIOTT, D. G., AND STONE.
A. J.
1902. THE DEER FAMILY. 334 pp. New York,
(132) RuBNER, K.
1927. DIE FORSTLICH-PFLANZENGEOGRAPHISCHEN VERHALTNISSE DES
NORDLICHEN FENNOSKANDIENS. Forstwiss. Centbl. 49: 185-211,
225-245.
(133) SAARI, EINO.
1923. [FOREST FIRES IN FINLAND, WITH SPECIAL REFERENCE TO STATE
FORESTS.] KULOISTA, ETUPAASSA SUOMEN VALTIONMETSIA SIL-
MALLA PITAEN. Acta Forest. Fenn. 26: 1-155. [English sum-
mary, pp. 143-155.]
(134) SARVAS, R.
1937. (BEOBACHTUNGEN UBER DIE ENTWICKLUNG DER VEGETATION AUF
DEN WALDBRANDFLACHEN NORD-FINNLANDS.] HAVAINTOJA KAS-
VILLISUUDEN KE:inTYKSESTA POHJOIS-SUOMEN KULOALOILLA.
Silva Fenn. 44, 64 pp.
(135) ScHANZ, ALFRED B.
(136)
(137)
(138)
(1;39)
(140)
1893. THE FOURTH OR NUSHAGAK DISTRICT. In Report on Population
and Resources of Alask11 at the Eleventh Census: 1890. pp.
91-97. U. S. Dept. of the Interior, Census Office.
SCHIERBECK, OTTO.
1931. FORESTRY vs. GAME COVER. Canad. Field Nat. 45 (2): 28-30.
SCHRADER, F. c ..
1901. PRELIMINARY REPORT ON A RECONNAISSANCE ALONG THE CHANDA-
LAR AND KOYUKUK RIVERS, ALASKA, IN 1899. U. S. Geol. Survey
Ann. Rpt. (1899-1900) 21 (Pt. 2): 441-486, illus.
---AND SPENCER, ARTHUR CoE.
1901. THE GEOLOGY. AND MINERAL RESOURCES OF A PORTION OF THE
COPPER RIVER DISTRICT, ALASKA. U. S. Geol. Survey. 94 pp.,
ill us.
SCHW ATKA, FREDERICK.
1900. REPORT OF A MILITARY RECONNAISSANCE MADE IN ALASKA IN 1883.
In Compilation of Narratives of Explorations in Alaska. U. S.
Senate (56th Cong., 1st Sess.) Rpt. 11 (1023): 283-362.
1894. A SUMMER IN ALASKA. 418 pp. St. Louis.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 103
(141) SETON, ERNEST THOMPSON.
1929. LIVES OF GAME ANIMALS. Vol. 2, Pt. 2, pp. 369-746, illus.
(142)
(143)
(144)
(145)
(146)
(147)
(148)
(149)
(150)
(151)
(152)
(153)
(154)
(155)
(156)
(157)
(158)
(159)
Garden City, N.Y.
1929. LIVES OF GAME ANIMALS. Vol. 3, Pt. 1, 412 pp., i!lus. Garden
City, N.Y.
SHIMKIN, DEMITRI B.
1951. FORT YUKON, ALASKA. AN ESSAY IN HUMAN ECOLOGY, I. 50 pp.
Alaska Development Board, Juneau. [Processed.]
SHIRAS, GEORGE, III.
1912. THE WHITE SHEEP, GIANT MOOSE AND SMALLER GAME OF THE
KENAI PENINSULA, ALASKA. Nat. Geog. Mag. 23 (5): 423-514.
SHOSTAKOVITCH, V. B.
1925. FORBST CONFLAGRATIONS IN SiBERIA, WITH SPECIAL REFERENCE
TO THE FIRES OF 1915. Jour. Forestry 23: 365-371.
SKUTCH, ALEXANDER F.
1929. EARLY STAGES OF PLANT SUCCESSION FOLLOWING FOREST FIRES.
Ecology 10: 177-190.
STOECKELER, E. G.
1948. IDENTIFICATION AND EVALUATION OF ALASKAN VEGETATION FROM
AIRPHOTOS WITH REFERENCE TO SOIL MOISTURE AND PERMAFROST
CONDITIONS. A PRELIMINARY PAPER. U. S. Dept. of the Army,
Corps of Engineers, St. Paul District, Field Operations Branch,
Permafrost Division. 103 pp. [Processed.]
STOECKELER, JOSEPH H.
1948. THE GROWTH OF QUAKING ASPEN AS AFFECTED BY SOIL PROPERTIES
AND FIRE. Jour. Forestry 46: 727-737.
SUMMERHAYES, v. S., AND WILLIAMS, P. H.
1926. STUDIES ON THE ECOLOGY OF ENGLISH HEATHS. II. EARLY STAGES
IN THE RECOLONIZATION OF FELLED PINEWOOD AT OXSHOTT.HEATH
AND ESHER COMMON, SURREY. Jour. Ecology 1_4: 203-243.
TABER, STEPH;EN.
1943. PERENNIALLY FROZEN GROUND IN ALASKA: ITS ORIGIN AND
HISTORY. Geol. Soc. Amer. Bul. 54: 1433-1548.
TAMM, 0LOF.
1950. NORTHERN CONIFEROUS FOREST SOILS. (Translated from the
Swedish by Mark L. Anderson.) 253 pp. Oxford.
TENGWALL, T. A.
1928. (DER ZUWACHS UND DIE BIOLOGIE DER RENNTIER-FLECHTEN IN DEN
TORNE ·uND LULE LAPPMARKEN.] RENLAVARNAS TILLVAXT OCH
BIOLOGI I TORNE OCH LULE LAPPMARKER. Svensk Bot. Tidskr.
22: 18-32.
THOMAS, GEORGE B.
1900. ALASKA.-1898. FROM MIDDLE FORK OF SUSHITNA RIVER TO
INDIAN CREEK. In Compilation of Narratives of Explorations
in Alaska. U. S. Senate (56th Cong., 1st Sess.) Rpt. 11 (1023):
733-735.
TORREY, RAYMOND H.
1932. MARCHANTIA POLYMORPHA AFTER FOREST FIRES. Torreya 32:
9-10.
1932. ANOTHER REPORT OF MARCHANTIA POLYMORPHA AFTER FOREST
FIRES. Torreya 32: 128-129.
TowNSEND, CHARLES WENDELL.
1911. CAPTAIN CARTWRIGHT AND HIS LABRADOR JOURNAL. 385 pp.
Boston.
TURNER, L. M. . .
1886. CONTRIBUTIONS TO THE NATURAL HISTORY OF ALASKA. U.S. Army,
Signal Corps, Arctic Series 11, 226 pp., iflus.
TYRRELL, J. B. ;
1934. JOURNALS OF SAMUEL HEARNE AND PHILIP TURNOR BETWEEN THE
YEARS 1774 AND 1792. 611 pp. Toronto. u. s. CENSUS OFFICE.
1893. -REPORT ON POPULATION AND RESOURCES OF ALASKA AT THE
ELEVENTH CENSUS: 1890. U. S. Dept. of the Interior, Census
Office. 282 pp.
104
(160)
(161)
(162)
(163)
(164)
(165)
'I'ECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
U. S. FOREST SERVICE.
1931. FIRE HINDERS CONVERSION OF ASPEN TO PINE AND SPRUCE. U. S.
Forest Serv., Lake States Forest Expt. Sta. Tech. Note 34, 1 p.
[Processed.]
U. S. OFFICE OF TERRITORIES.
1951. MID-CENTURY ALASKA. U. S. Dept. of the Interior, Office of
Territories, 155 pp.
VoGLER, PAuL.
1901. UEBER DIE VERBREITUNGSMITTEL DER SCHWEIZERISCHEN ALPEN-
PFLANZEN. Flora 89: 1-137.
W ALLACE1 ROBERT E.
1948. CAVE-IN LAKES IN THE NABESNA, CHISANA, AND TANANA RIVER
VALLEYS, EASTERN ALASKA. Jour. Geology 56: 171-181.
WIEDEMANN, EILHARD. '
1925. ZUWACHSRUCKGANG UND WUCHSSTOCKUNGEN DER FICHTE IN DEN
MITTLEREN UND UNTEREN HOHENLAGEN DER SACHSISCHEN STAATS•
FORSTEN. Ed. 2. 190 pp. Akademische Buchhandlung Wa.lter
Laux, Tharandt i. Sa.
WooLFE, HENRY D.
1893. THE SEVENTH OR ARCTIC DISTRICT. Jn Report on Population f•nd
Resources of Alaska at the Eleventh Census: 1890. pp. 129-152.
U. S. Dept. of the Interior, Census Office.
APPENDIX
Check List of Plant Species Collected
Lichens
Alectoria jubata (L.) Ach.
A. nigricans (Ach.) Nyl.
A. pubescens (L.) Howe
Baeomyces placophyllus Ach.
Buellia papillata (Sommer£.) Tuck.
Cetraria cucullata (Bell.) Ach.
0. hiascens (E. Fries) T. Fries
0. islandica (L.) Ach.
0. juniperina (L.) Ach.
0. nivalis (L.) Ach.
0. richardsonii (Hook.) Tuck.
0. tilesii Ach.
Oladonia alpestris (L.) Rabenh.
0. alpestris f. aberrans des Abbayes
0. amaurocraea (Floerke) Schaer.
0. amaurocraea f. celotea (Ach.) Vainio
0. amaurocraea f. jasciculata Kernst.
0. cimaurocraea f. oxyceras (Ach.) Vainio
0. bellidijlora (Ach.) Schaer.
0. cariosa (Ach.) Spreng.
0. cariosa f. corticata Vainio
0. cariosa f. cribrosa (W allr.) V ainio
0. cariosa f. squamulosa (Mull.-Arg.) Vainio
0. cenotea (Ach.) Schaer. f. crossota (Ach.) Nyl.
0. chlorophaea (Floerke) Spreng. f. simplex (Hoffm.) Arn.
0. coccijera (L.) Willd. .
0. coniocraea (Floerke) Spreng. f. stenoscypha (Stuckenb.) Sandst.
0. cornuta (L.) Hoffm. f. cylindrica Schaer.
I
l
I
I
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 1 05
0. cornuta f. scyphosa Schaer.
0. cornutoradiata (Co em.) Sandst.
0. crispata (Ach.) Flot. var. injundibulifera (Schaer.) Vainio
0. crispata var. virgata (Ach.) Vainio
0. dejormis (L.) Hoffm.
0. degenerans (Floerke) Spreng. f. cladomorpha (Ach.) Vainio
0. degenerans f. euphorea (Ach.) Floerke
0. degenerans f. gracilescens Floerke
0. ecmocyna (Ach.) Nyl. var. nigripes (Nyl.) Evans
O.jurcata (Huds.) Schrad. var. racemosa (Hoffm.) Floerke
O.jurcata var. racemosa f. corymbosa (Ach.) Vainio
0. gonecha (Ach.) Asahina
0. gracilis (L.) Willd. var. chordalis (Floerke) Schaer.
0. gracilis var. chordalis f. leucochlorea Floerke
0. gracilis var. chordal is f. platydactyla (W allr.) V ainio
0. gracilis var. dilatata (Hoffm.) V ainio
0. gracilis var. elongata (Jacq.) E. Fries
0. gracilis var. elongata f. laontera (Del.) Arn.
0. lepidota Nyl.
0. mitis Sandst.
0. multiform is Merrill f. finkii (V ainio) Evans
0. multiformis f. simulata Robbins
0. multiformis f. subascypha (Vainio) Evans
0. pleurota (Floerke) Sc.haer. f. extensa (Ach.) Sandst.
0. pseudorangiformis Asahina
0. pyxidata (L.) Hoffm. var. neglecta (Floerke) Mass.
0. pyxidata var. pocillum (Ach.) Flot.
0. rangiferina (L.) Web.
0. rangiferina f. stygia E. Fries
0. scabriuscula (Del.) Leight.
0. scabriuscula f. adspersa (Floerke) Sandst.
0. scabriuscula f. sublevis Sandst.
0. scabriuscula f. surrecta (Floerke) Sandst.
0. squamosa (Scop.) Hoffm. f. muricella (Del.) Vainio
0. squamosa (Scop.) Hoffm. f. turjacea Rehm.
0. sylvatica (L.) Hoffm.
0. uncialis (L.) Web.
0. verticillata (Hoffm.) Schaer. f. aggregata (Del.) Oliv.
0. verticillata f. evoluta (T. Fries) Stein.
Dactyl ina arctica (Hook.) N yl.
Diploschistes scruposus (Schreb.) Norm.
Dujourea madreporiformis (Wulf.) Ach.
Ephebe solida Born.
Evernia mesomorpha N yl.
Fulgensia bracteata (Hoffm.) Ras. ·
Haemdtomma ventosum (L.) Mass. var. lapponicum (Ras.) Lynge
Icmadophila ericetorum (L.) Zahlbr.
Lecanora subjuscata Magn.
Lecidea rubiformis Wahl.
Lob aria lin ita (Ach.) Rabh.
L. pulmonaria (L.) Hoffm.
Nephroma arcticum (L.) Torss.
N. expallidum N yl.
106 TECHNICAL BULLETIN 1133, U. S. DEPT~ OF AGRICULTURE
Lichens-Continued
Ochrolechia jrigida (Swartz) Lynge
Parmelia alpicola T. Fries
P. omphalodes (L.) Ach.
P. sulcata Tayl.
P. vittata (Ach.) Nyl.
Parmeliopsis hyperopia (Ach.) Vainio
Peltigera aphthosa (L.) Willd. var. aphthosa
P. aphthosa var. variolosa (Mass.) Thoms.
P. canina (L.) Willd.
P. canina var. rufescens (Weis.) Mudd
P. canina var. spuria (Ach.) ~chaer.
P. canina var. spuria f. sorediata Schaer.
P. malacea (Ach.) Funck
P. membranacea (Ach.) Nyl. emend. Thoms.
P. pulverulenta (Tayl.) N yl.
Ramalinafarinacea (L.) E. Fries
Stereocaulon paschale (L.) Hoffm.
S. paschale var. alpinum (Laur.) Mudd
S. paschale var. alpinum f. gracilentum (T. Fries) M. Lamh
S. paschale var. grande H. Magn.
S. paschale var. grande f. velutinum (Frey) M. Lamb
S. tomentosum E. Fries
S. tomentosum var. alpestre Flot.
S. vesuvianum Pers. var. arcticum (Lynge) M. Lamb
Thamnolia vermicularis (Swartz) Ach.
Usnea comosa (Ach.) Rohl. ssp. comosa
U. scabiosa Mot.
Mosses
Aulacomnium palustre (Web. & Mohr) Schwaegr.
A. turgidum (Wahl.) Schwaegr.
Brachythecium albicans (Hedw.) BSG.
B. salebrosum (Web. & Mohr) BSG.
Bryum caespiticium Hedw.
B. cuspidatum (BSG.) Schimp.
B. turbinatum (Hedw.) Schwaegr.
B. uliginosum (Brid.) BSG.
Oalliergon stramineum (Brid.) Kindb.
Oamptothecium lutescens (Hedw.) BSG.
Oampylium stellatum (Hedw.) Lange & C. Jens.
Oeratodon purpureus (Hedw.) Brid.
Olimacium dendroides (Hedw.) Web. & Mohr
Oratoneuron jilicinum (Hedw.) Roth
Dichodontium pellucidum (Hedw.) Schimp.
Dicranella grevilleana (Brid.) Schimp.
Dicranum bergeri Bland.
D. drummondii C. Miill.
D. elongatum Schleich ..
D. fragilifolium Lindh.
D. fuscescens Turn.
D. majus Smith
D. muhlenbeckii BSG.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 107
D. strictum Schleich.
Distichium capillaceum (Hedw.) BSG.
Ditrichum flexicaule (Schwaegr.) Hampe
Drepanocladus aduncus (Hedw.) Warnst.
D. jluitans (Hedw.)Warnst
D. uncinatus (Hedw.) Warnst.
Eurhynchium praelongum (Hedw.) Bryhn.
E. stubstrigosum Kindb.
Hylocomium splendens (Hedw.) BSG.
Hypnum crista-castrensis Hedw. (syn. Ptilium crista-castrensis (Hedw.)
De Not.).
H. dieckii Ren. & Card.
H. imponens Hedw.
H. lindbergii Mitt.
H. revolutum (Mitt.) Lindh.
Leptobryum pyrijorme (Hedw.) Schimp.
Meesia uliginosa Hedw.
Mnium affine Bland.
M. spinulosum Bruch & Schimp.
Oncophorus wahlenbergii Brid.
Paludella squarrosa (Hedw.) Brid.
Philonotis fontana (Hedw,) Brid.
Plagiothecium denticulatum (L.) Br. Sch.
Pleurozium schreberi (Brid.) Mitt.
Pohlia nutans (Hedw.) Lindh.
P. wahlenbergii (Web. & Mohr) Andrews
Polytrichum commune Hedw.
P. juniperinum Hedw.
P. piliferum Hedw.
P. strictum Brid.
Rhacomitrium canescens Brid.
R. lanuginosum (Hedw.) Brid.
Rhytidium rugosum (Hedw.) Kindb.
Rhytidiadelphus trig_uetrus (Hedw.) Warnst.
Sphagnum capillaceum (Weiss)· Schrank
S. capillaceum var. tenellum (Schim.p.) Andrews
S. fuscum (Schimp.) Klinggr.
S. girgensohnii Russ.
S. plumulosum Roll
S. rubellum Wils. o
S. teres (Schimp.) Angstr.
Tetraplodon mnioides (Hedw.) BSG.
Thuidium abietinum (Brid.) BSG.
T. delicatulum (Hedw.) Mitt.
Timmia austriaca Hedw. ·
Tomenthypnum nitens (Hedw.) Loeske
Tortella fragilis (Hook. & Wils.) Limpr.
Liverworts
Lophozia porphyroleuca (Nees) Schiffn ..
Marchantia polymorpha L.
Preissia quadrata (Scop.) Nees
Ptilidium ciliare (L.) Nees
108 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Grasses
Agropyron latiglume (Scribn. & Smith) Rydb.
A. subsecundum (Link) Hitchc.-Bearded wheatgrass
A. trachycaulum (Link) Malte--Slender wheatgrass
Agrostis scabra Willd.-Bentgrass
Alopecurus aequalis Sobol.-Shortawn foxtail
A. alpinus J. E. Smith-Alpine foxtail
Arctagrostis latijolia (R. Br.) Griseb.
Bromus arcticus Shear-Arctic brome
B. pumpellianus Scribn.-Pumpelly brome
B. pumpellianus var. villosissimus Hult.
Calamagrostis canadensis (Michx.) Beauv.-Bluejoint reedgrass
C. inexpansa A. Gray.,-Northern reedgrass
C. neglecta (Ehrh.) Gaertn., Mey., & Schreb.-Slimstem reedgrass
C. purpurascens R. Br.-Purple pinegrass
Deschampsia atropurpurea (Wahl.) Scheele-Mountain hairgrass
D. caespitosa (L.) Beauv.-Tufted hairgrass
Elymus innovatu.'! Beal-Fuzzyspilm wildrye
Festuca altaica Trin.-Altai fescue
F. ovina L.--Sheep fescue
F. ovina var. brachyphylla (Schult.) Piper-_,;tipine sheep fescue
F. rubra L.-Red fescue
F. rubra var. lanuginosa Mert. & Koch-Hairyscale red fescue
Hierochloe alpina (Swartz) Roem. & Schult.-Alpine sweetgrass
H. odorata (L.) Beauv.-Sweetgrass
Hordeum jubatum L.-Foxtail barley
Phleum alpinum L.-Alpine timothy
Poa alpina L.-Alpine bluegrass
P. arctica R. Br.-Arctic bluegrass
P. glauca Vahl-Greenland bluegrass
P. interior Rydb.-Inland bluegrass
P. paucispicula Scribn. & Merr.-Alaska bluegrass
P. pratensis L.-Kentucky bluegrass
P. stenantha Trin.-Trinius bluegrass
Trisetum spicatum (L.) Richt.-Spike trisetum
Grasslike Plants
Carex aquatilis Wahl.-Water sedge
C. bigelowii Torr.-Bigelow sedge
C. canescens L.
C. capillaris L.
C. concinna R. Br.
C. diandra Schrank
C. disperma Dew.
C. eburnea Boott
C. garberi Fern. var. bifaria Fern.
C. loliacea L.-Ryegrass sedge
C. lugens Holm
C. macrochaeta C. A. Meyer ·
C. maritima Gunn. (syn. C. incurva Light£.)
C. media R. Br.
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 109
0. membranacea Hoole
0. mertensii Prescott-Mertens sedge
0. podocarpa R. Br.
0. praticola Rydb.
0. rossii Boott-Ross sedge
0. rostrata Stokes-Beaked sedge
0. scirpoidea Michx.
0. supina Willd. ssp. spaniocarpa (Steud.) Hult.
0. vaginata Tausch.
Eleocharis palustr·is (L.) Roem. & Schult.-Commori spikesedge
Eriophorum brachyantherum Trautv:.
E. scheuchzeri Hoppe-Scheuchzer. cottonsedge
E. vaginatum L.·-Sheathed cottonsedge ·
Juncus alpinus Vill.-Alpine rush
J. castaneus J. E. Smith ·
J. drummondii E. Meyer
Luzula multiflora (Retz.) Lejeune'
L. parvifiora (Ehrh.) Desv.-Millet woodrush
L. rujescens Fisch.
L. S'udetica (Willd.) DC. (syn. L. campestris (L.) DO. var. alpina
Gaudin) -Sudetic woodrush
L. wahlenbergii Rupr.-Wahlenberg woodrush
Scirpus cespitosus L. var. callosus Bigel.-Oallous deerhair bulrush
Triglochin palustris L.·-Arrow podgrass
Forbs
Achillea borealis Bong.-Arctic yarrow
Aconitum delphinifolium DO.
A. delphinifolium ssp. paradoxum (Reichenb.) Hult.
A. maximum Pall.
Actaea arguta N utt.-Western baneberry
Androsace lehmanniana Spreng.-Lehmann rockjasmine
A. septentrionalis L.-Northern rockjasmine
Anemone narcissifiora L. ssp. interior Hult.-Narcissus anemone
A. richardsonii Hook.-Richardson anemone
Antennaria monocephala DC ..
A. nitida Greene
A. oxyphylla Greene
Aguilegia brevistyla Hook.-Yukon columbine
A.-formosa Fisch.·-Sitka columbine
Arabis hirsuta (L.) Scop. var. pycnocarpa (M. Hopkins) Rollins-
Common hairy rockcress
A. holboellii Hornem.-Holboell rockcress
A. holboellii var. retrofracta (Graham) Rydb.
A. lyrata L. ssp. kamchatica (Fisch.) Hult.
Arenaria laterijlora L.-Bluntleaf sandwort
A. macrocarpa Pursh-Long-podded sandwort 1
A. obtusiloba (Rydb.) Fern.-Alpine sandwort '
A. rubella (Wahl.) J. E. Smith
A. stricta (Swartz) Michx.-Rock sandwort
Arnfca latifolia Bong.~Broadleaf arnica
A. louiseana Farr ssp. jrigida (Meyer) Maguire
110 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Forbs-Continued
Artemisia arctica Less.-Arctic wormwood
Aruncus dioicus (Walt.) Fern.-Sylvan goatsbeard
Aster sibericus L. -Siberian aster
Astragalus alpinus L.-Alpine milkvetch
A. americanus (Hook.) M. E. Jones-Arctic milkvetch
A. tananaicus Hult.-Tanana milkvetch
A. yukonis M. E. Jones-Yukon milkvetch
Athyrium filix1emina (L.) Roth ssp. cyclosorum (Rupr.) C. Chr.-
Ladyfern
Boschniakia rossica (Cham. & Schlecht.) B. Fedtsch.-Poque
Boykinia richardsonii (Hook.) Rothr. (syn. Therofon richardsonii
(Hook.) 0. Kuntze)-Richardson boykinia
Bupleurum americanum Coult. & Rose_:_ Thoro wax
Galla palustris L.-Wild calla
Oampanula alaskana (A. Gray) Wight-Alaska bellflower
0. lasiocarpa Cham.-Behring bellflower
Oardamine bellidifolia L.-Daisyleaf bittercress
0. umbellata Greene-Umbel-flowered bittercress
Castilleja hyperborea Pennell-Paintedcup
0. pallida (L.) Kunth ssp. caudata Pennell
0. pallida ssp. mexiae (Eastw.) Pennell
Oerastium arvense L.-Starry cerastium
Chenopodium capitatum (L.) Aschers.-Blite goosefoot
Chrysanthemum leucanthemum L. var. pinnatifidum Lecoq & Lamotte-
Field oxeyedaisy
Ohrysosplenium tetrandrum (Lund) T. Fries----:-Fourstamen goldsaxi-
frage
Oicuta mackenzieana Raup-Mackenzie waterhemlock
Oircaea alpina L.-Alpine circaea
Olaytonia sarmentosa C. A. Mey.-Alaska springbeauty
Oomandra livida Richards.-Northern comandra
Oonioselinum cnidiifolium (Turcz.) Pors.-Dawson hemlockparsley
Oorallorhiza mertensiana Bong.-Paci:fic coralroot
0. trifida Chatelain-Early coralroot
Corydalis sempervirens (L.) Pers.-Pale corydalis
Orepis elegans Hook.-Hawksbeard ·
0. nana Richards.-Tiny hawksbeard
Oryptogramma acrostichoides R. Br.-American rockbrake
0. stelleri (GmeL) Prantl-Slender rockbrake
Oypripedium passerinum Richards.-Canada ladyslipper
Oystopteris jragilis (L.) Bernh. -Brittle bladderfern
Delphinium brownii Rydb.-Browns larkspur
D. glaucum Watson-Sierra larkspur
Descurainia sophioides (Fisch.) 0. E. Schultz--:-Northern tansymustard
Diapensia lapponica L. ssp. obovata (Fr. Schmidt) Hult.-Arctic
diapensia
Draba aurea Vahl-Golden draba
D. borealis DC.-Northern draba
Drosera rotundifolia L.-Roundleaf sundew
Dryopteris austriaca (Jacq.) Woynar, Schinz, & Thellung-Spreading
woodfern
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 111
D. disjuncta (Ledeb.) C. V. Mort.-Oakfern
D.jragrans (L.) Schott-Fragrant woodfern
Epilobium adenocaulon Hausslm.-Sticky willowweed
. E. anagallidifolium Lam.
E. angustifolium L.-Fireweed
E. latifolium L.-Red willowweed
E. leptocarpum Hausskn.
E. palustre L.
Equisetum arvense L.-Field horsetail
E~ pratense Ehrh.-Meadow horsetail
E. scirpoides Michx.-Sedgelike horsetail
E. sylvaticum L.-Sylvan horsetail
E. variegatum Schleich.-Variegated horsetail
Erigeron acris L. var. asteroides (Andrz.) DC.-Bitter fleabane
E. lonchophyllus Hook.-Spearleaf fleabane
E. peregrinus (Pursh) Greene-Peregrine fleabane ·
E. purpuratus Greene-Fleabane
Fritillaria camschatcensis (L.) Ker-Gawl.-Kamchatka fritillary
Galium boreale L.-Northern bedstraw
G. triflorum Michx.-Sweetscented bedstraw ·
Gentiana acuta Michx. var. plebeja (Cham.) Wettst.-Northern
gentian
G. detonsa Rottb.-Gentian
G. glauca Pall.-Bluegreen gentian
G. propinqua Richards.-Gentian
Geranium erianthum DC.-Geranium
Geum macrophyllum Willd.~Largeleaf avens
G. rossii (R. Br.) ser.-Ross avens
Goodyera repens (L.) R. Br. var. ophioides Fern.-Creeping rattlesnake-
plantain
Habenaria dilatata (Pursh) Hook.-White bogorchid
H. hyperborea (L.) R. Br.-Northern green habenaria
H. obtusata (Pursh) Richards.-Bluntleaf habenaria
Hedysarum alpinum L. ssp. americanum (Michx.) Fedtsch.-American
sweetvetch
H~ mackenzii Richards.-Mackenzie sweetvetch
'Heracleum lanatum Michx.-Common cowparsnip
Heuchera glabra Willd.-Alumroot
Hieracium triste Willd.-Hawkweed
Hippuris vulgaris L.-Marestail
Latlfyrus palustris.L. ssp. p-ilosus (Cham.) Hult.-Hairy ma.rsh pea-
. vme
Leptarrhena pyrolifolia (D. Don) Sk-Leather-leaf saxifrage
Lesquerella arctica (Wormskj.) S. Wats.-.Arctic bladderpod
Linnaea borealis L. var. americana (Forbes) Rehd.-American twin-
flower
Listera cordata (L.} R. Br.-Northern listera
Lupinus arcticus S. Wats.-Arctic lupine
L. ndotkatensis Donn-Nootka lupine
L. polyphyllus Lindl.-Washington lupine
Lycopodium alpinum L.-Alpine clubmoss.
L. annotinum L.-Bristly clubmoss ·
L. clavatum L.-Runningpine
349169-56--8
112 TECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICULTURE
Forbs-Continued
L. clavatum var. monostachyon Grev. & Book.
L. complanatum L.-:-Groundcedar
L. selago L.-Fir clubmoss
Melandrium taimyrense A. Tolmatchev
Menyanthes trifoliata L.-:-Common bogbean
Mertensia paniculata (Ait.) G. Don-Panicle bluebells
Mimulus guttatus DC.-Common monkeyflower
Mitella pentandra Hook.-Fivestamen miterwort
Moneses uniflora (L.) .A. Gray-Woodnymph
Myosotis alpestris F. W. Schmidt-Alpine forgetmenot
Myriophyllum exalbescens Fern.-Parrotfeather
Nuphar polysepalum Engelm.-Rocky Mountain cowlily
Orchis rotund if alia Banks-Roundleaf orchis
Osmorhiza obtusa (Coult. & Rose) Fern.-Bluntseed sweetroot
Oxyria digyna (L.) Hill-Alpine mountain-sorrel
Oxytr()pis campestris (L.) DC.-Plains crazyweed
0. campestris var, varians (Rydb.) Barneby-Variable plains crazy-
weed
0. maydelliana Trautv.-Maydell crazyweed
0. nigrescens (Pall.) Fisch.-Blackish crazyweed
0. scammaniana Hult.-8camman crazyweed
0. splendens Dougl.-Showy crazyweed
0. viscida Nutt. var. subsucculenta (Hook.) Barneby-Yellowhair
crazyweed
Parnassia kotzebuei Cham. & Scblecht.-Kotzebue parnassia
P. palustris L.-Wideworld parnassia
Pedicularis capitata Adams-Pedicularis
P. labradorica Wirsing-Labrador pedicularis
P. lanata Cham. & Scblecht.-Woollyspike pedicularis
P. parvijlora J. E. Smith-Smallfiower pedicularis
P. sudetica Willd.-Sudetic pedicularis
P. verticillata L.-Whorled pedicularis
Petasites .frigidus (L.) E. Fries-Arctic butterbur ("sweet coltsfoot")
P. sagittatus (Pursh) A. Gray-Arrowleaf butterbur ("sweet colts-
foot")
Pinguicula villosa L.-Hairy butterwort
Polemonium acutiflorum Willd.
P. boreale .Adams-Arctic polemonium
P. caeruleum L. ssp. villosum Brand.-Greekvalerian polemonium
[>. pulcherrimum Hook.-Skunkleaf polemonium
Polygonum alaskanum (Small) Wight-Alaska knotweed
P. bistoria L. ssp. plumosum (Small) Hult.-Feathery European his-
tort
P. viviparum L.-Viviparous bistort
Potentilla norvegica L. ssp. monspeliensis (L.) Aschers. & Graebn.-
Montpelier cinquefoil
P. palustris (L.) Scop.-Marsh cinquefoil
P. pensylvanica L.-Pennsylvania cinquefoil
P. pensylvanica var. strigosa Pursh
Primula cunei:folia Ledeb. ssp. saxifragifolia (Lehm.) Hult.-Saxifrage
primrose ·
_/
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 113
Pulsatilla ludoviciana Heller-American pasquefl.ower
Pyrola asarifolia Michx. var. incarnata (Fisch.) Fern,-Alpine pyrola
P. grandijlora Radius-Bigfl.ower pyrola
P. minor L.-Snowline pyrola
P. secunda L.-Sidebells pyrola
P. virens Schweigger (syn. P. chlorantha Swartz)-Green pyrola
. Ranunculus cymbalaria Pursh--Bhore buttercup
R. occidentalis Nutt.-Western buttercup
R. repens L.-Creeping buttercup.
R. trichophyllus Chaix-Hairleaf watercrowfoot
Rorippa palustris (L.) Besser var. hispida (Desv.) Rydb.-Hairy bog
marsh cress
Rumex arcticus Trautv.-Arctic dock
Sanguisorba menziesii Rydb.--'-Menzies burnet
S. stipulata Raf.
Saussurea angustijolia (Willd.) DC.-Narrowleaf saussurea
Saxijraga bronchialis L. ssp. funstonii (Small) Hult.-Funston saxi-
frage ·
S. eschscholtzii Sternb.-Eschscholtz saxifrage
S. hieracijolia Waldst. & Kit.-Hawkweed saxifrage
S. oppositijolia L.-Twinleaf saxifrage
S: punctata L. ssp. pacifica Hult. -Dotted saxifrage
S. rivularis L. -Stream bank saxifrage
S. tricuspidata Rottb. -Three bristle saxifrage
Sedum rosea (L.) Scop. ssp. integrijolium (Raf.) Hult.-Roseroot
stonecrop ·
Selaginella sibirica (Milde) Hieron. -Siberian selaginella
Senecio atropurpureus (Ledeb.) Fedtsch. ssp. frigidus· (Richards.)
Hult.-Arctic groundsel
S. congestus (R. Br.) DC. var. palustris (L.) Fern.-Swamp groundsel
S. integerrimus Nutt.-Lambstongue groundsel
S. paucijlorus Pursh
S. pauperculus Michx.-Balsam groundsel
S. resedifolius Less.-Mignonette groundsel
Silene acaulis L.-Moss silene
S. williamsii Britt.-Williams silene
Smilacina stellata (L.) Desf.-Starry solomonplume
Solidago multiradiata Ait.
S. oreophila Rydb.
Sparganium angustijolium Michx.-Narrow leaf burreed
Stellaria calycantha (Ledeb.) Bong.-Bongard starwort
S. ciliatosepala Trautv.
S. longipes Goldie-Longstalk starwort
Streptopus amplexijolius (L.) DC.-Claspleaf twistedstalk
Swertia perennis L.-Alpinebog swertia .
Taraxacum·alaskanum Rydb.-Alaska dandelion
T. lapponicum Kihlm.-Lapland dandelion
Thalictrum sparsijlorum Turcz. -Meadowrue
Tojieldia coccinea Richards. -Purple tofieldia i
T. pusilla (Michx:) Pers.-Small tofieldia
Torularia humilis (C. A. Mey.) 0. E. Schulz-Northern rockcress
Trientalis europaea L. ssp. arctica (Fisch.)-Hult.-Arctic starfl.ower
Typha latijolia L. -Common cattail
.)
114 TECHNICAL l3ULLETJN 113 3, U. S. DEPT. OF AGRICULTURE
. Forbes-Continued
Urtica lyallii S. Wats.-Lyall nettle
Valeriana capitata Pall.
V. capitata var. bracteosa (Britt.) Hult.
Veronica wormsk.iotdii Roem. & Schult.-Wormskjold speedwell
Viola adunca J. E. Smith-Hook violet
V. epipsila Ledeb. ssp. repens (Turcz.) W. Bckr.-Creeping violet
V. renifolia Gray var. brainerdii (Greene) Fern.-Brainerd violet
Zigadenus elegans Pursh-Mountain deathcamas
Trrt_es and Shrubs
Alnus crispa (Ait.) Pursh-American green alder
A. sinuata (Reg.) Rydb.-Sitka alder
A. tenuijolia Nutt.-Thinleaf alder
Amelanchier alnifolia Nutt.-Saskatoon serviceberry
A. florida Lindl.-Pacific· serviceberry
Andromeda polifolia L. -Bogrosemary andromeda
Arctostaphylos alpina (L.) Spreng. ssp. rubra Hult.-Redalpine bear-
berry
A. uva-ursi (L.) Spreng. -Bearberry
Artemisia alaskana Rydb. -Alaska sagebrush
-A. borealis Pall.-Northern wormwood
A. dracunculus L. -Tarragon
A. frigida Willd.-Fringed sagebrush
A. tilesii L~deb. var. elatior Torr. & A. Gray
Betula Xeastwoodae Sarg.-Yukon bitch
B. glandulosa Michx.--:-Bog bitch
B. nana L. ssp. exilis (Sukatch.) Hult.-Dwarf arctic bitch
B., papyrijera Marsh. var. humilis (Reg.) Fern. & Raup-Alaska
paper bitch ·
B. papyrifera Marsh. var. kenaica (W. H. Evans) A. Henry-Kenai
paper bitch
Oassiope stelleriana (Pall.) DC.-Starry cassiope·
0. tetragona (L.) D. Don-Fitemoss cassiope
Oornus canadensis L. -Bunch berry dogwood
0. stolonifera Michx.-Redosier dogwood .
Dryas alaskensis Porsild-Alaska dryad
D. drummondii Richards.-Drummond dryad
D. hookeriana Juz.-Hooker dryad
D. ·octopetala L.-Mt. Washington dryad
D. punctata Juz.
Elaeagnus commutata Bernh. -Silver berry
Empetrumnigrum L.-Black crowberry
Juniperus communis L. var. saxatilis PalL-Mountain common
juniper
J. horizontalis Moench-Creeping juniper
Larix laricina (Du Roi) K. Koch-Eastern larch
Ledum palustre L. ssp. decumbens (Ait.) Hult.-Sprawlirig crystaltea
ledum ·
L. palustre ssp. groenlandicum (Oeder) Hult.-Labrador-tea ledum
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 115
Loiseleuria procumbens (L.) Desv.-.Alpine-azalea
Luetkea pectinata (Pursh) Kuntze-Luetkea
Menziesia ferruginea J. E. Smith-Rusty menziesia
Oplopanax horridus (J. E. Smith) Miq.-An:J.erican devilsclub
Oxycoccus microcarpus Turcz. -Small cranberry
Picea glauca (Moench) Voss-White spruce
P. glauca var. porsildi Raup-Porsild spruce
P. Xlutzii Little-Lutz spruce
P. mariana (Mill.) B.S. P.-Black spruce
P. sitchensis (Bong.) Carr. -Sitka spruce
Populus balsamifera L. -Balsam poplar
P. tremuloides Michx.-Quaking aspen
P. trichocarpa Torr. & A. Gray-Black cottonwood
Potentilla fruticosa L. -Bush cinquefoil
Rhododendron lapponicum (L.) Wahlen b.-Lapland rhododendron
Ribes hudsonianum Richards.-Hudson Bay currant
R. lacustre (Pers.) Poir.-Prickly currant
R. triste Pall.-American red currant ·
Rosa acicularis Lindl.-Prickly rose
Rubus alaskensis Bailey-.Alaska bramble
R. chamaemorus L. -Cloud berry
R. idaeus L. var. strigosus (Michx.) Maxim.-American red raspberry
R. pedatus J. E. Smith-Fiveleaf bramble ·
R. stellatus J. E. Smith-Nagoonberry
Salix alaxensis (Anderss.) Cov.-Feltleaf willow
S. alaxensis var. Zongistylis (Rydb.) Schneid.-Bluetwig feltleaf willow
S. anglorum -cham.-Northland willow
S. arbusculoides Anderss.-Little tree willow
S. arbusculoides var. glabra Anderss. -Smooth littletree willow
S. arctica PalL-Arctic willow
S. arctica var. obcordata Ball-Bluntleaf arctic willow
S. barclayi Anderss.-Barclay willow
S. barclayi var; angustijolia Anderss.
S. bardayi var. hebecarpa Anderss.
S. barclayi var. rotundijolia Anderss.
S. bebbiana Sarg.-Bebbwillow
S, bebbiana var. perrostrata (Rydb.) Schneid. -Smooth Bebb willow
S. commutata Bebb-Undergreen willow
S. glauca L. -Graylea:f willow
S. glauca var. acutijolia (Hook.) Schneid.
S. glauca var. aliceae Ball ·
S. myrtillijolia Anderss.-Blueberry willow
S. pseudomonticola Ball-Park willow
S. pulchra Cham.-Diamondleaf willow
S. pulchra var. palmeri Ball-Palmer diamoildleaf willow .
S. pulchra var. yukonensis Schneid.-Yukon diamondleaf willow
S. reticulata L. _:_ N etleaf willow
S. reticulata var. subrotundata Ser.-Round netiJaf willow
S. richardsonii Hook.-Richardson willow
S. rotundijolia Trautv.~Least willow
S. scouleriana B::~,i-r. ~Scouler willow
S. setchelliana Ball~SetcheUwillow
116 'l'ECHNICAL BULLETIN 113 3, U. S. DEPT. OF AGRICULTURE
Trees and Shrubs-Continued
S. · sitchensis Sanson -8itka willow
S. walpolei (Cov. & Ball) Ball-Walpole willow
Sambucus callicarpa Greene -Pacific red elder
Shepherdia canadensis (L.) Nutt.-Russet buffaloberry
Sorbus scopulina Greene-Greenes mountain-ash
Spiraea beauverdiana Schneid. -Beauverd spirea
Tsuga mertensiana (Bong.) Sarg.-Mountain hemlock
Vaccinium cespitosum Michx.-Dwarf blueberry
V. uliginosum L. -Bog bilberry
V. vitis-idaea L. -Cow berry
Viburnum edule (Michx.) Raf. (syn. Viburnum pauciflorum La
Pylaie)-Moose berry viburnum
Soil Analyses
Soil samples were collected from several of the plots on the -Kenai
Peninsula in 1949 and subjected to laboratory analyses for various
properties (tables 10-26). Mechanical analyses followed the method
of Bouyoucos (17). The data are presented in terms_ of both the
American and the International systems. Other analyses followed
the methods-outlined by Peech et al. (112). · --
Soil horizons were designated by Arabic numerals, except as indi-
cated, rather than by the commonly employed A, B, C terminology.
This was done because the genetic relations of the horizons were not
clear. In all cases the 10 horizon represented unincorporated organic
matter that frequently was not separable into L, F, and H layers.
Horizon 1 usually corresponded approximately to an A2 horizon and
the deepest layer represented in a given· profile usually corresponded
approximately to the C horizon. In several profiles from recently
burned areas a supplementary set of samples were collected. In the
records these are designated by Roman numerals. Layer I represented
the uppe!'most mineral soil to the base of the A2 horizon; layer U, the
upper part of layer I; layer III, the lower part of layer I; and-layer IV,
the upper part 'of the B horizon.
Horizon
2.0-
1.0
L--------'-0.10
2-----------.16 g ___________ .06 4 ___________ .39
5-----------.07 6 ___________ 1.10
TABLE lO.~Mechanical analysis of soil, Plot PIPJ-1 1
[Values represent percentages]
American system (fractions mm.) I
-International system
{fractions mm.)
I
l.Q---0.5-0.25-0.10-005-1 <0.005 2.0-0.2--0.02-1 <O 002 0.5 0.25 0.10 0.05 o:oo2 <o.oo2 0.2 0.02 0.002 .
-------------
1. 72 9.44 15.20 9. 74 50.32 13.48 15.72 16.15 44.03 26.34 13.48
. 42 3. 45 12.38 12.90 59.97 10.72 16.40 7.42 48.44 3_3. 42 10.72
.23 3.00 13.57 11.44 58.90 12.80 16.15 6.68 51.36 29.16 12.80
.68 4.87 9.03 9.94 65.58 9. 51 15.92 9.08 53.71 27.70 9. 51
. 21 1-63 4. 54 9.12 74.93 9. 50 15;90 3.24 57.52 29.74 9.50
1.83 10.79 19. 71 9.03 42.10 15.44 19.90 21.42 44.05 19.09 15.44
I For information on the forest cover on this plot, see table 8.
;~; 0
~
Horizon
1. ..........
2 ...........
3 ...........
4 ...........
5 ...........
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA: 117
2.o-
1.0
0.10
.05
.11
.11
4. 30
TABLE 11.-Mecha.nical analysis of soil, Plot P49-5 1
[Values represent percentages]
American system (fractious mm.) International system
(fractions mm.)
0.5-I 0.25-I 0.10-l.Q-0.05-<0.002 <0.005 2.0-0.2-. 0.02-<0.002 0.5 -~~-_!_~~~~ 0.002 0.2 0.02 0.002
0.28 3. 58 13.65 10.47 59.38 12.54 16.23 7.48 46.49 33.49 i2. 54
.33 3.33 9.30 13.60 63.58 9.81 15.78 6.22 56.65 27.30 9.81
.15 2.10 5. 70 8.03 69.12 14.79 19.58 4.12 49.22 31.87 14.79
.25 .45 1. 60 10~30 79.01 8.28 8.88 1. 06 67.85 22.81 8.28
6.33 14.43 16.89 11.43 31.30 15.32 18.95 30.97 37.98 15.73 15.32
I For information on the forest cover on this plot, see table 8.
Horizon
2.0-
1.0
1. .......... 0.44
2 ........... 1.42
3 ........... . 54
4 ........... .34
TABLE 12.-Mechanical analysis of soil, Plot P49-91
[Values represent percentages]
American system (fractions mm.) International system
(fractions mm.)
I r.o-I 0.5-0.25-1 0.1o-l 0.05-<0.002 <0.005 2.0-0.2-0.02-<0.002 ~~~~ 0.002 0.2 0.02 0.002
0. 65 6.48 14.89 8. 58 57.15 11.81 15.48 12.62 45.42 30.15 11.81
1. 93 6.44 13.53 10.46 54.09 12.13 16.94 13.92 46.14 27.81 12.13
.71 4. 89 12.60 9.03 60.28 11.95 17.72 10.35 47.19 30.51 11.95
. 51 2.02 7.83 7. 02 56.10 26.00 34.73 4.57 41.41 28.02 . 26.00
I For information on the forest cover on this plot, see table 8.
Horizon
TABLE l3.-111echanical analysis of soil, Plot PJ,9-12 1
I
[Values represent percentages]
American system (fractions mm.) International system
(fractions mm.)
2.o-11.0-I 0.5-I 0.25-1 0.10-1 0.05-., <O 0021 <O 005 2.0-I 0.2-I 0.02-1 <O 002 1.0 0.5 0.21\ 0.10 0.05 0.002 . . 0.2 0.02 0.002 .
L:::::::: 0:f! 0:~~ I n~ f~:&~ fU~ J~:gg fU~ iU~ ~:~ ~n~ ~~:8~ fr:8~
3........... .10 .10 12.25 30.76 31.42 22.85 12.52 14.77 6.37 71.47 9.64 12.52
4........... -------2.18 40.04 35.06 14.38 8.34 10.58 7.35 77:80 6.51 8.34
L:::::::: 1.92 --1~12· 1:~ -i~:~~ ~~:~~ !&J~ 1~:~g 1~:8~ n~ ~U~ 2~:~~ 1~:~g
1 For information on the forest 9over on this plot, see table 8.
Horizon
1. .......... .
2 .......... .
3 .......... .
4 .......... ..
2.0-
1.0
0.13
TABLE 14.-1\tlechanical analysis of soil, Plot P49-16 1
[Values represent percentages]
I
American system (fractions mm.) ·International system
(fractions mm.)
1.0-1 o.5-0.25-0.10-1 o.o5-<:o 002 <o 005 .tl.o-I o.z.. 0.02-1 <o 002 0.5 0.25 0.10 0.05 O.D02 · · f 0.2 . 0.02 0.002 · . I ---
.66 1. 23 6. 21 15. 44 14. 27 52. 50 9. 69 13. 48 12. 58 54. 99 22. 7 4 9. 69 ... I-;; '"' --;,;-.. M ~-;:;;--;;:;;--;;:~r:; u ---;_-;;
.13 . 38 4. 50 13. 26 12. 04 59. 28 10. 41 13. 06 8. 59153. 86 27. 14 10. 41
.71 1. 34 4. 86 8. 34 5. 96 56. 35 22. 44 28. 10 9. 67 34. 93 32. 96 22. 44
1 For information on the forest cover on this plot, see table 4.
ll8 TECHNICAL BULLETIN 1133, U. S. DEPT. OF AGRICULTURE
Horizon
!_ __________
2-----------
3-----------4 ___________
-
TABLE 15.-Mechanical analysis of soil, Plot P49-20 1
[Values represent percentages
American system (fractions mm.) International system
(fractions mm.)
2.0-1.0-0.&-0.25-0.10-0.05-<0.002 <0.005 2.0-0.2-0.02-<0.002 1.0 0.5 0.25 0.10 0.05 0.002 0.2 0.02 0.002
-------------------------
0.03 0.04 4.03 15.44 10._54 58.45 11.47 16.79 8.48 49.95 30.10 11.47
-------.35 1. 85 9. 97 17.04 61.21 9. 55 11.83 3. 98 64.26 22.21 9. 55
.05 .12 2.13 8.90 11.74 62.40 U.66 17.96 4. 55 _52. 50 28.29 14.66
-------.54 5.02 20.30 21.59 47.31 5.24 8.46 10.22 70.04 14.50 5.24
' For information on the forest cover on this plot, see table 3.
Horizon
l_ __________
2 ___________
3-----------4 ___________
5-----------
TABLE 16.-Mechanical analysis of soil, Plot P49-24 1
[Values represent percentages]
American system (fractions mm.) International system
(fractions mm.)
2.0-1.0-0.5-0.25-0.10-0.0&-<0.002 <0.005 2.0-0.2-0.02-<0.002 1.0 0.5 0.25 0.10 0.05 C.002 0.2 0.02 0.002
-----------------------
0.05 0.39 4.93 12.61 11.34 60.81 9. 87 16.66. 10.03 46.57 33.53 9.87
-------.11 1.82 11.72 13.51 58.81 14.Q3 19.80 4.49 51.98 29.50 14.03
.29. 1. 05 9.08 21.82 10.48 44.09 -13/19 16.96 18.01 44.09 24.71 13.19
.15 1. 64 16.52 20. 5.1 5.26 37.40 18.48 25.41 27.77 27.92 25.83 18.48
1. 51 4. 70 40.46 42.97 4.26 2.48 3.62 5.22 68.05 24.72 3.61 3. 62
t For information on the forest cover on this plot, see table 6.
Horizon
l_ __________
2 ___________
3 ___________ 4 ___________
5 ___________
Horizon
l_ __________
2 .. -----.----
3-----------4 ___________
5.----------
2.0-
1.0
';['ABLE 17.-Mechanical analysis of soil, Plot P49-29
[Values represent percentages]
American system (fractions mm.) International system
(fractions mm.)
1.0-0.5-0.2&-0.10-0.05-<0.002 <0.005. 2.0-0.2-0.02-<0.002 0.5 0.25 0.10 0.05 0.002 0.2 0.02 0.002
-----------------------
-------0.48 4.19 16.02 11.31 57.15 10.85 16.17 8.14 52.76 28.25 10.85
0.17
.34
.18
5.26
2.0-
1.0
0.08
.11
.16
.• 07
10.89
.29 2.63 11.40 8.40 65.05 12.06 15.39 5. 93 51.22 30.79 12.06
0 67 0 59 8.87 6.41 71.12 12.00 15.32 4.44 52.92 30.64 12.00
.42 1.03 2.56 3.37 82.66 9. 78 14.06 2.41 49.49 38.32 9. 78
6.12 13.22 18.12 11.45 '36.13 9. 70 12.93 30.27 41.25 18.78 9. 70
TABLE lB.-Mechanical analysis of soil, Plot P49-33
[Values represent percentages]
American system (fractions mm.) International system
(fractions mm.)
1.0-o.&-0.25-0.10-0.05-<0.002 <0.005 2.0-0.2-0.02-<0.002 0.5 0.25 0.10 0.05 0.002 .0.2 0.02 0.002
---------------------
0.42. 3.18 13.17 9. 50 60.'73 12.92 17.63 6.51 49.62 30.95 12.92
0 72 3.41 10.80 8. 75 63.12 13.09 17.87 6. 76 50.85 29.30 13.00
.17 0 75 3. 78 4.39 80.90 9.85 14.58 2.18 52.86 35.11 9.&5
.35 1.00 2. 61 5.82 81.43 8. 72 13.38 2.07 56.58 32.63 8. 72
13.22 15.44 15.15 6.87 30.79 7;64 10.25 45.28 30.80 16.28 7.64
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 119
-------·-·
TABLE 19.-Mechanical analysis of soil, Plot P49-37
[Values represent percentages]
American system (fractious mm.) International system
(fractions mrn.)
Horizon
12.0-1.0-
'-----------:::0
0.5
0.53
2 ----------1 .07 .42 3 .. _________ . 21 .85 4 ___________ .32 1. 35 5. __________ 1. 83 7.29
0.5-0.25--0.10-0.05-<0.002 <0.005 2.0-1 0.2-0.25 0.10 0.05 0.002 0.2 0.02
-----
5.32 16.43 10.59 56.15 10.88 16.21 10.03 50.78
4.00 13.05 9.18 60.12 13.07 17.43 8. 67 47.55
4.96 10.95 7. 74 64.46 10.8:l 15.12 9.83 50.11
6. 51 9. 53 8.31 66.26 7. 72 13.40 11.92 51.73
30.18 27.94 7. 62 19.51 5. 63 7. 24 54.37 31.75
TABLE 20.-Moisture equivalents of soils
[Values represent percentage of dry weight]
Plot
Horizon
0.02-
0.002
28.31
30.71
29.23
28.63
8.25
p 49-24 p 49--37 P49--33
<0.002
10.88
13.07
10.83
7. 72
5. 63
P49--~9
L .. ------------------------------------____ ----------------29.41 32. 88 27.30 33. 45
2----------------------------------------------------------· 32.52 32.22 26.40 37.08
3 ______________ ---------------------------------------------34. 22 24.32 22. 40 30. 10
4·----------------------------------------------------------53.74 18.76 17.70 24.06
5.----------------------------------------------------------3.15 S. 45 9. 53 11.40
I --------------------------------------------------------------------34.68 27.42-26.50 26.73 rr__________________________________________________________ __________ 48.15 21.42-24.78 21.12
III.--------------------------------------------------------------------------------------------------
IV---------------------------------------------.------------____ ._____ _ 29.88 27. 79-28. 68 30.92
'l'ABLE.21.-Hydrogen-ion concentmtion (pH) .of soils 1
[ Plot
Horizon I . ·
----P49--121~~1 P49-5 1~-=::=.J P49--161~9--20 I P49-241~9--371 P49--33 P49-29
lo ________ 4.02 4.57 4.64 4.44 4.30 4.49 4.44 5.03 4.31 4~87
1 .. --------4.21 4.68 .'i.09 4.47 4.31 4.53 5.42 4.93 4.96 4.81
2.--------5.38 li.45 5.16 5.25 5.47" 5.89 5.79 5.45 5.68 5.48
g_________ 5.77 5.68 5.82 5.70 6.14 5.94 5.90 5.61 5.55 5.93
4_________ 5.75 5.83 5.52 6.22 6.35 5.71 5.70 S.37 5.44 5.62
5_________ 5.81 5.82 5. 76 ---------------------------6.03 5. 79 5.62 5. 74 o_________ 5. 64 5. 77 ______________________________________________________________________ _
!_ ________ ---------------·------------ ------------------ --------- ---------6. 25 6. 43 6. 74 ~¥~====== =========!========= ========= ========r======r:::::::.::::::::: i: ~g u~ H~
' For information on the forest cover on these plots, see tables 3, 4, 6, and 8.
110 TECHNICAL BULLETIN/1133, U. S~ DEPT. OF AGRICULTURE
T ,;.BLE 22.~0rganic matt~r cont.~nt of soils i
-.
[Values represent loss-on-ignition, percent]
Plot
Horizon 1---------------.----,----,-------,-------,---.---
---P49--121 P49--1 P49--5 P49--9 P49~16 P49--20 _ P49-24 P49--37 P49-33 P49--29
ln.-------64. 56 80. 23 83. 53 78. 82 .82. 50 61. 06 67. 24 38. 55 37. 52 35. 38
l_________ "8.98 5.47 6.35 9.74 9.58 11.24 8.56 12.83 12.16 10.96
2.--------14.96 9.28 13.77 8.58 10.60 7.19 7.57 8.13 6.14 12:29
3_.:______ 4.59 7.49 6.15 5.26 4.03 5.58 8.62 4.19 4.13 5.74
4_________ 3.4! 4.78 2.58 2.61 2.08 2.37 11.22 3.18 2.96 3.52
5_________ 2.80 4.77 1.97 ---------------------------1.52 1.75 2.2!\ 2.06
.6.......... 2. 71 3.02 --------- --------- ------------------ --------- ---------------------------
1 ........ --------- ------------------------------------------------------13.80 12.19 4.40 nr::::: ::::::::: ::::::::: ::::::::: :::::::::!::::::::: ::::::::: ::::::::: ~g: !g !: r~ r ~~
1 For information on the forest cover on these plots, see tables 3, 4, 6, and 8.
TABLE 23.-Total nitrogen content of soils I
_[Values in percentage of dry weight]
Plot
Horizon 1-----,-------,----,------,-----,----c-----,---·--,----,----
P49--12 P49--1 P49--5 P49-9 P49-16 P49--20 P49--24 P49--37 P49-1l3 P49--29
1o........ 1.021 1.268 1.294 1.425 1.356 1.241 1.300 0.633 0.609 0.443
1. ....... : .162 .118 .109 .159 .162 .181 .161 . 267 .164 .197
2_________ .237 .145 .245 .121 .177 .104 .106 .133 .075 .. 275
3 ___ .______ .067 .125 .089 .078 .066· .079 .138 .057 .047 .075
4.~-------.045 (2) .003 \~) .022 .034 .234 .040· ,034 .046
5......... . 041 . 001 . 020 ------------------ ---------. 016 . 018 . 022 . 022
6_________ .028 .042 ------------------------------------------------------------------------
1_ ________ --------- ------------------------------------------------------.034 .264 .083 rr________ _________ _________ _________ _________ _________ _________ _________ . 623 . 220 .094
IIL ...... ------------------ ---------.... c •••• --------- --------- ---------• 304 .115 .106
IY -------------------------------------~----------------------- ---------.163 . 086 . 069
1 For information on the forest cover on these plots, see tables 3, 4, 6, and 8;
'Trace.
TABLE 24.-Readily available phosphorus content of soils I
[Values represent parts per million of soil]
Plot
Horizon I-,-----,----------------,---,-----.-----.--:-,,---
· P49--12 P49--1 P49--5 P49--9 P49--16 P49--20 P49--24 P49-37 P49--33 P49--29
lo........ 131 205 258 227 375 272 115 71 65 75
l_________ 4 39-60 19 46 65 1 . 22 41 48
2_________ (2) (2) 38 (2) 6 2 (2) (2) 11 11
3......... 2 (2) 2 2 13 9 2 2 9 1
4_________ 6 16 1)5 147 274 76 3 11 14 7
5.________ 10 11 106 ------------------ ---------25 38 85 32
6......... 51 68 --------- --------- ------------------ --------- --------- ------------------
1_ ________ ------------------_____ , ___ --------------------------- ---------248 172 60
II ________ ---------------------------··------------------------- ---------725 272 55
IlL ______ -----------------· ------------------------------------ ---------39 56 45
IV ....... ,---------~---------......... ·-----------------------------------4 10 2
1 For information on the forest cover on these plots, see tables 3, 4,-6, and 8.
• Trace.
(
ECOLOGICAL EFFECTS OF FOREST FIRES IN ALASKA 121
TABLE 25.-Exchangeable potassium in soils I
[Values are percentages of dry weight]
Plot
Horizon J----,----,---,---,---,----,----,------:----.---.---
P49-12 P49-1 P49-5 P49-9 P49-16 P49-20 P49-24 P49-37 P49-33 P49-29
1•--------0.0385 0.0494 0.0427 0.0700 0.1619 0.0566 0.0443 0.0337 0.0268 0.0340
L--------.0120 .0092 .0089 .0125 .0089 .0109 .0071 .0151 .0139 .0242
2_________ .0129 .0106 .0174 .0117 .0107 .0085 .0082 .0078 .0081 .0163
3---------.0104 .0140 .0122 .0095 .0091 .0072 .0102 .0062 .0088 .0098
4_--------. 0081 . 0123 . 0077 . 0038 . 0052 . 0063 . 0103 . 0063 . 0086 . 0098
5_________ .0099 .0097 .0048 ---------------------------.0036 .0055 .0066 .0060
6---------. 0067 . 0085 --------- --------- ------------------------------------------------------
L ________ ---------------------------------------------------------------.0252 .0276 .0364
II ________ ---------------------------------------------------------------.0316 .0340 .0331
IlL ______ -----------------·----------------------------------------------.0216 .0138 .0241
IV _______ ---------.------------------------------------------------------.0178 .0143 · .0122
' I
I For information on the forest cover on these plots, see tables 3, 4, 6, and 8.
TABLE 26.-Exchangeable calcium in soils 1
[Values are percentages of dry weight]
Plot
Horizon J----,-----,---,-----,-----,---,-----,----,---,---
P49-12 P49-1 P49-5 P49-9 P49-16 P49-20 P49-24 P49-37 P49-33 P49-29
10--------0.1283 0. 2390 0.1933 0. 2685 0. 5072 0.1808 0.1924 0. 2915 0.1062 0. 2892 L ________ .0348 .0512 .0510 .0413 .0408 .0477 .0536 .0582 .0716 .0677 . 2 _________ . 1073 .0500 .0321 .0330 .0818 .0541 .0480 .0257 .0156 .0500
3---------.0329 .0315 .0266 . 0413 .0332 .0357 .0488 .0146 .0112 .0268 4 _________ .0229 .0425 .0167 .1664 .1044 . 0161 .0531 .0107 .0129 .0119 5 _______ :_ .0219 .0442 .0535 ---------------------------.0146 .0101 .0136 .0072 6 _________ .0675 .0270 ------------------------------------ ------------------------------------L ________ ---------------------------------------------------------------.3666 .2380 .0564 IL _______ ---------------------------------------------------------------. 7426 . 2623 .0763 IlL ______ --------------------------------------------- ------------------.2056 .0552 .0335 rv _______ --------- ---------
--------- --------- ---------------------------. 0643 .0326 .0182
I For information on the forest cover on these plots, sec tables 3, 4, 6, and 8.
i
11. S. GOVERNMENT PRINTING OFFICE.: 1955
For sale by the Superintendent of Documents U. S., Government Printing Office, Washirigton 25, D. C
Price 40 cents
(