HomeMy WebLinkAboutPhase II Stand Inventory UAF Yakutat final report_draft 9.22.13
National
Forest
Foundation
Community
Capacity
and
Land
Stewardship
Program
Yakutat
Foreland
Sustainable
Rotation
Analysis
and
Forest
Planning
City
and
Borough
of
Yakutat,
and
UAF
Alaska
Center
for
Energy
and
Power
September
22,
2013
**
note:
this
draft
is
considered
final
by
both
PI,
however
the
final
draft
is
pending
review
by
ACEP
director
and
Department
of
Natural
Resources
State
Forester
Amanda
Byrd,
Biomass
Coordinator,
ACEP
Bill
Lucey,
Planning
Director,
City
and
Borough
of
Yakutat
The
City
and
Borough
of
Yakutat
and
the
Yak-‐Tat
Kwaan
Village
Corporation
have
been
exploring
various
biomass
energy
options
for
over
three
years.
Investigations
included
a
trial
crop
plantation
of
various
willow,
alder,
and
poplar
varieties.
Growth
rates
were
slow
to
start,
but
the
results
of
this
plantation
are
yet
to
be
quantified.
A
more
immediate
alternative
may
be
using
small
diameter
wood
harvested
as
part
of
pre-‐commercial
thinning.
Volume
and
growth
metrics
are
needed
to
determine
the
amount
of
wood
that
could
be
sustainably
harvested
in
both
commercial
and
pre-‐commercial
thinning.
A
grant
was
awarded
to
the
City
and
Borough
of
Yakutat
from
the
USDA
National
Forest
Foundation
to
conduct
a
forest
inventory
on
the
natural
regrowth
in
areas
that
had
previously
been
clear-‐cut
for
commercial
sale.
The
area
measures
around
25,000
acres,
or
10,120
hectares.
Crews
conducted
a
stand
inventory
using
twenty
five
transects
measuring
200
m
long
and
geospatially
distributed
across
age
class.
The
stand
inventory
should
inform
managers
to
estimate
standing
biomass
in
each
age
class,
and
offer
a
potential
harvest
rate
for
thinning,
and
natural
regrowth
rate.
Introduction
The
community
of
Yakutat,
located
on
the
northern
coast
of
the
Gulf
of
Alaska,
has
expressed
interest
in
biomass
energy
as
an
alternative
to
diesel
fuel.
Before
a
biomass
heating
system
can
be
installed,
the
biomass
resources
need
to
be
quantified.
Yakutat
has
many
sources
of
biomass
including
recovered
tree
stumps,
cordwood
washed
onto
Cannon
Beach,
and
abundant
standing
Sitka
spruce
(Picea
sitchensis
(Bong.)
Carr)
and
western
hemlock
forests
(Tsuga
heterophylla
(Raf.)).
From
1952
through
1990,
Sitka
spruce
and
Western
Hemlock
in
the
area
of
Yakutat
was
harvested
through
standard
clear-‐cut
methods
for
commercial
sale.
Other
trees
naturally
occurring
this
area
include
the
pioneer
species
Sitka
alder
(Alnus
sitchensis)
and
willow
varieties
(Salix
sp.)
(Shephard,
1995).
Casual
observation
through
remote
sensing
indicated
that
the
growth
rates
in
the
harvest
area
varies
by
age
and
location.
The
regrowth
of
the
forest
since
the
clear-‐cut
harvest
had
not
been
fully
investigated,
and
while
pre-‐commercial
thinning
has
been
identified
as
a
biomass
resource,
the
availability
and
sustainability
of
this
resource
had
not
been
measured.
This
report
provides
information
on
the
availability
of
forest
thinnings
as
a
biomass
resource
based
on
transect
data
collected
in
July
and
August
of
2013.
Methods
Twenty
five
200
m
long
transects
were
selected
from
62
randomly
placed
transects
on
a
map
of
Yakutat
with
forest
harvest
date
overlays
produced
by
the
ArcMap
program.
The
survey
transects
were
randomly
placed
using
rules
for
road
access,
but
not
across
a
road
or
stream
channel.
The
survey
transects
were
selected
by
diversity
of
landscape,
diversity
of
age
class,
and
replicability.
Two
additional
transects
(63
and
64)
were
added
to
increase
robustness
in
a
large
1971
harvest
area.
In
an
attempt
to
survey
as
much
land
as
possible,
and
gather
useable
data,
a
transect
and
area
plot
survey
method
was
employed
whereby
along
a
200
m
long
transect,
3-‐20
m
diameter
area
surveys
were
conducted.
Transects
were
traversed
with
the
use
of
a
Trimble
Nomad
GPS,
compass,
and
hip-‐
chain
for
accurate
measurements.
The
center
of
each
survey
area
was
photographed,
each
tree
was
measured
at
diameter
at
breast
height
(DBH),
and
the
species
recorded.
As
a
means
to
cover
more
ground,
this
was
reduced
to
two
quarters.
Up
to
5
trees
were
selected
based
on
size
ranges
for
age
determination
by
bore-‐coring.
Tree
rings
were
counted
in
the
field
for
speed
of
data
collection,
and
for
ease
of
handling
data
collected.
Photographs
were
taken
of
cores.
The
area
sampled
is
expressed
in
a
per
hectare
unit.
Figure
1.
Transect
and
area
plot
survey
method
for
inventory
survey.
Survey
areas
(blue
circles)
are
20
m
diameter,
and
the
areas
were
65m
apart
on
the
transect
line.
65
m 130
m
195
m
Start
Transec
t
0
m
Transects
were
started
at
least
50
m
from
roadways
to
avoid
edge
effects,
and
direction
of
the
survey
transect
was
altered
if
it
was
likely
to
extend
into
an
areas
along
a
roadside
which
tends
to
have
a
higher
rate
of
growth.
Results
and
discussion
The
basal
area
of
trees/ha
re-‐established
in
the
1952/57
clear
cut
areas
averaged
43.7
m2/ha
with
an
average
tree
size
of
0.002m2
(Table
1).
These
trees
have
regenerated
well
and
were
larger
than
the
areas
with
later
harvests
(0.009
m2
and
0.006
m2).
In
fact,
the
three
age
groups
were
significantly
different
in
basal
area/ha
(Table
2).
In
the
1952/57
areas,
the
understory
of
smaller
trees
was
naturally
thinning,
and
the
number
of
stems
per
hectare
ranged
between
551-‐1717,
whereas
in
the
19771/79
and
1983/89
areas
this
averaged
3565
and
2842
respectively.
Interestingly,
transect
16,
with
657
stems/ha
had
been
recently
thinned
(in
2011),
and
transect
5
with
551
stems/ha
was
naturally
thinning
through
light
shading
out
the
smaller
stems.
Table
1:
Average
survey
area
measurements
for
all
transects
per
cut
age
Year
Harvested
Mean
Basal
Area
/
Ha
(m2)
Mean
Basal
Area
/
Tree
(m2)
Mean
stems
/
ha
Mean
Age
1952/57
43.7
0.0024
975
37
1971/79
26.8
0.0009
3565
28
1983/89
6.4
0.0006
2842
18
Table
2:
One-‐way
ANOVA
results
for
transect
measurements
Measurement
DF
F
P-‐Value
Basal
area
per
ha
2,
22
20.56892
0.0000092*
Basal
area
per
tree
2,
22
39.25222
0.000000055*
Stems
per
ha
2,
22
2.060538
0.151268194
The
smaller
basal
area
in
the
1983/89
areas
was
due
in
part
to
the
smaller
basal
size
per
tree
(0.0006
m2)
and
the
smaller
number
of
stems/ha
(2843
stems/ha).
The
close
spacing
of
trees
in
both
the
71/79
and
1983/89
cut
areas
makes
growing
slow
for
all
of
the
trees.
In
some
cases,
a
tree
may
have
had
a
1
year
head
start
over
the
surrounding
trees
and
be
substantially
bigger.
This
was
indicated
through
the
bore
coring
samples.
Within
each
of
these
age
groups,
individual
tree
sizes
differed
significantly.
Typically,
a
10cm
diameter
tree
would
be
surrounded
by
several
2cm
trees,
though
the
ages
may
differ
by
just
one
year.
On
several
occasions
a
very
large
tree
would
stand
out,
and
upon
coring
a
detailed
story
emerged
like
the
116
year
old
tree
that
had
existed
before
the
clear-‐cut
as
a
very
small
tree.
As
the
other
trees
were
removed
the
tree
grew
over
the
next
25-‐30
years
into
a
55cm
giant.
This
occurrence
was
evident
in
many
1971/79
harvest
areas,
though
116
years
old
was
an
anomaly.
Figure
2.
Tree
cores
taken
at
survey
area
2.1
on
Transect
2
shows
two
25
year
old
Sitka
spruce
trees
and
a
15
year
old
spruce
with
very
different
diameters.
Different
spacing
of
the
trees
produces
very
different
tree
sizes.
The
trees
in
the
1952/57
harvest
areas
had
an
average
age
of
37
years
with
ages
ranging
from
27
through
48
years
old.
With
respect
to
the
ages
of
the
trees
cored,
it
has
taken
between
4
and
9
years
for
trees
to
re-‐establish
after
the
harvest.
Natural
regeneration
was
noted
on
Vancouver
Island
in
Canada
to
occur
4
years
after
clear-‐cutting,
and
the
best
medium
for
seedling
germination
is
mineral
soil,
followed
by
a
mixture
of
course
woody
debris,
soil
and
humus
(Peterson,
et
al.,
2007).
Peterson
et
al.
(2007)
also
noted
that
natural
regeneration
averaged
1976
seedlings
per
ha
of
Sitka
spruce,
and
log
surfaces
that
retain
litter
were
the
best
mediums
for
seed
germination.
The
survey
transects
often
traversed
areas
with
high
log
debris.
In
some
areas,
this
debris
can
be
substantial
including
rotting
remains
of
4ft
to
6ft
diameter
logs,
large
stumps,
many
with
trees
growing
from
or
near
them.
Average
biomass
per
hectare
was
estimated
(Table
3)
using
equation:
BM
=
Exp(β0+
β1
ln
DBH)
(Jenkins
et
al.,
2003)
where
the
parameters
β0
=
-‐20773
and
β0
=
2.3323.
This
equation
may
overestimate
smaller
diameter
biomass
as
it
is
designed
for
trees
2.5
cm
DBH
or
larger,
and
this
study
found
many
trees
below
2.5
cm
DBH.
There
are
no
other
reliable
equations
available
for
small
diameter
Sitka
spruce
in
Alaska,
though
one
could
be
produced
for
this
area
by
creating
an
allometric
equation
similar
to
a
study
on
small
diameter
Balsam
poplar
in
Southcentral
Alaska
(Byrd
2013).
Table
3:
Average
biomass
(kg)
per
hectare,
average
thinning
(kg/ha),
and
average
harvest
through
thinning
(tonne).
Date
Harvested
Mean
Biomass/ha
(kg)
Mean
stems/ha
25%
thinning
(t/ha)
/
(green)
50%
thinning
(t/ha)
/
(green)
25%
/
50%
thinning
(ton/ac)
1952/57
243,370
975
0
/
0
0/0
0/0
1971/79
138,822
3565
35
/
70
69
/
138
16
/
31
1983/89
33,196
2842
8
/
16
17
/
34
4
/
8
Trees
spacing
per
ha
has
naturally
or
manually
been
managed
to
be
between
550
and
1770
stems
per
ha
in
the
1952/57
harvest
areas.
In
the
1971/79
and
1983/85
clear-‐cuts,
the
forest
is
overstocked
in
many
areas
with
densities
up
to
8400
stems
per
hectare
(Table
4).
The
dense
stocking
slows
the
growth
down
of
individual
trees,
though
natural
competition
occurs
and
there
are
generally
dominant
trees.
These
areas
could
benefit
from
pre-‐commercial
thinning
–
the
practice
of
thinning
a
forest
of
small
diameter
trees
and
allow
for
selected
trees
to
be
able
to
grow
larger,
faster
without
the
competition.
Pre-‐commercial
thinning
should
be
undertaken
thoughtfully,
as
there
is
potential
for
wind
damage,
or
blowdown
to
occur
on
smaller,
unprotected
trees,
and
even
larger
sized
trees
without
adequate
protection
(Shultz
and
Heutte,
2005).
A
spacing
of
between
800
and
1400
trees/ha
was
suggested
by
Peterson,
et
al.,
(2007),
and
spacing
should
occur
before
age
20
to
maintain
optimal
crown
cover,
though
up
to
age
40
was
also
still
deemed
safe.
A
thinning
regime
to
bring
the
overstocked
forests
>2000
trees/ha
down
to
800
–
1400
would
require
leaving
between
7
m
(23ft)
and
12.5m
(41
ft)
between
trees
(Peterson
et
al.,
2007).
Assuming
a
final
density
of
1000
trees
per
hectare,
an
estimate
was
made
(Table
3)
on
the
amount
of
biomass
per
hectare
that
could
be
removed
through
pre-‐commercial
thinning.
The
1952/57
harvest
areas
already
have
a
low
density
of
trees,
and
thus
have
been
removed
from
thinning
calculations
in
the
report
though
select
harvest
is
planned
for
2014
to
determine
biomass
potential
from
these
stands.
The
1971/79
areas
have
shown
the
highest
average
density
of
trees
per
hectare,
and
an
average
of
138,822
kg/ha,
and
could
produce
an
average
35-‐69
tonnes
of
dry
biomass
per
hectare
through
25%
and
50%
thinning,
for
a
total
harvest
of
between
approximately
53,000
–
105,000
dry
tonnes.1
The
1983/89
areas
have
an
average
density
of
2842
trees
per
hectare;
with
an
average
standing
biomass
estimate
of
33,196
kg/ha.
Through
pre-‐commercial
thinning,
these
areas
could
produce
an
average
of
8
–
17
tonnes/ha
of
biomass
at
25%
and
50%
thinning,
for
a
total
harvest
of
up
to
61,000
–
129,000
tonnes
of
dry
biomass.2
1
These
calculations
assume
that
the
1971/79
harvest
areas
account
for
15%
or
1,518
hectares
of
the
total
clear
cut
area
2
These
calculations
assume
that
the
1981/89
harvest
areas
account
for
75%
or
7,588
hectares
of
the
total
clear
cut
area
However,
it
is
imperative
to
acknowledge
that
these
numbers
have
been
developed
from
a
total
of
25
transects,
covering
1.77
hectares
in
a
total
of
10,117
hectares
that
can
be
very
variable
in
its
forest
stands
due
to
soil,
landscape
differences,
and
proximity
to
streams
and
other
water
beds.
For
more
precise
numbers,
more
data
would
need
to
be
collected.
Some
specific
areas
would
not
be
well
served
by
thinning
due
to
sparse
regrowth
(Table
4).
These
areas
already
have
a
low
stand
density.
Transect
19
was
recently
thinned
and
all
of
the
cut
material
remains
in
the
area.
Table
4
shows
a
compilation
of
data
from
the
survey
transects.
This
can
be
used
a
guide
for
those
particular
areas,
but
not
for
the
entire
forest
in
that
unit.
The
biggest
hurdle
that
must
be
overcome
in
a
pre-‐commercial
thinning
project
is
determining
the
cost
per
tonne
of
biomass
harvested
through
thinning,
and
the
cost
of
transportation
to
the
boiler,
and
determining
the
feasibility
of
all
areas.
A
harvest
time
and
motion
study
would
produce
an
economic
analysis
of
the
harvest
and
delivery
costs.
Assuming
it
is
economic
to
access
and
harvest
all
areas
viable
for
pre-‐commercial
thinning,
a
harvest
rate
of
up
to
2000
tonnes
per
year
would
be
sustainable
for
43
years.
This
number
is
based
on
the
25%
and
50%
total
average
thinning
of
overstocked
forest
inventories
from
the
both
the
1971/79
and
1983/89
harvest
areas.
Again,
these
numbers
are
averages
based
on
a
small
survey
size.
More
extensive
survey
information
is
required
to
verify
these
numbers.
Conclusion
A
large
scale
biomass
heating
project
in
Yakutat
could
conservatively
use
1000
tonnes
of
woody
biomass
per
year.
Ensuring
a
sustainable
biomass
resource
supply
will
be
imperative
for
the
success
of
a
biomass
heating
system.
A
pre-‐commercial
thinning
project
would
provide
benefit
to
both
the
forest
itself
in
allowing
faster
regeneration
of
larger,
commercial
size,
high-‐value
saw
logs,
and
to
the
community
of
Yakutat
for
a
biomass
heating
system.
Understanding
the
economics
of
harvesting
the
wood
through
a
thinning
regime
will
determine
whether
the
project
is
economically
viable
using
this
wood
resource.
Recommendations
• Conduct
a
time
and
motion
harvest
study
to
assess
to
the
economics
of
harvesting
wood
through
thinning
• Collect
wood
from
Transect
area
19
as
the
start
of
a
biomass
stockpile
• Look
towards
a
chip-‐fired
system
to
use
the
harvested
wood
• Look
for
chipping
equipment
and
storage
facilities
for
the
size
and
type
of
chip
required
• Focus
on
1971/79
harvest
areas
before
the
1983/89
areas
as
these
stands
are
older,
and
better
developed
to
withstand
effects
of
high
winds,
and
will
produce
more
biomass
per
hectare
Table
4.
Average
survey
information
for
each
transect
conducted.
Transect
Number
Year
harvested
Basal
Area
per
ha
(m2)
Basal
Area
per
Tree
(m2)
Stems
per
Ha
Biomass
Kg/Ha
Mean
age
Thinning
25%
(ton/ha)
Thinning
50%
(ton/ha)
18
1952/57
69.5
0.0019
1717
346,544
37
-‐
6
1952/57
39.9
0.0030
657
281,106
37
-‐
5
1952/57
21.8
0.0021
551
102,460
37
-‐
17
1979
47.3
0.0009
3565
210,000
30
52,500
105,000
57
1971
37.6
0.0007
5024
154,892
26
38,723
77,446
63
1971
36.6
0.0010
3222
151,175
34
37,794
75,587
64
71
35.7
0.0011
2629
148,091
32
37,023
74,045
2
72
(83?)
34.9
0.0008
3650
145,219
21
35,305
72,609
9
1940
(71)
34.7
0.0008
4982
132,702
28
33,172
66,351
43
1971
27.5
0.0008
6742
228,737
28
57,184
114,368
52
1971
27.5
0.0010
2226
121,660
21
30,415
60,830
11
1979
25.9
0.0012
982
136,482
32
-‐
-‐
44
1971
21.7
0.0007
3650
86,266
26
21,566
43,133
10
1979
20.1
0.0016
716
93,744
29
-‐
-‐
4
1972
17.5
0.0006
5300
142,618
33
35,655
71,309
49
1972
(83?)
15.6
0.0006
3650
53,099
21
13,275
26,549
50
1985
13.0
0.0005
4897
43,225
17
10,806
21,612
30
1985
9.1
0.0005
4176
57,772
16
14,443
28,886
7
1985
8.8
0.0004
8459
55,212
16
13,803
27,606
19
1982
7.9
0.0011
583
33,677
26
-‐
-‐
26
1985
7.5
0.0005
2162
26,186
18
6,546
13,093
40
1985
3.8
0.0007
1039
31,489
25
-‐
-‐
3
1985
2.6
0.0004
2184
17,113
13
4,278
8,557
51
1985
2.1
0.0006
1039
14,391
17
-‐
-‐
1
1985
2.6
0.0006
1039
19,701
16
-‐
-‐
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