HomeMy WebLinkAboutAEA Railbelt Biomass Report State Lands v2
ESTIMATES OF AVAILABLE BIOMASS ON RAILBELT
IN INTERIOR AND SOUTHCENTRAL ALASKA
April 10, 2024
By Miho Welton, Statewide Inventory Forester, Alaska Division of Forestry and
Fire Protection on behalf of the Alaska Energy Authority – Biomass Program
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Introduction
This report is prepared to provide estimates on the amount of biomass in accessible areas of the
state forest and state forest classified lands in interior and southcentral Alaska using the existing
forest inventory and road data. Tanana Valley State Forest (TVSF) is the largest state forest in
Alaska extending over 450 miles from near the Canada border westward to the confluence of the
Yukon and Tanana Rivers (Figure 1). The most recent inventory was completed in 2013 on
2,873,239 acres of the state forest lands and the adjacent state forest classified lands. There is no
state forest in southcentral Alaska, but Alaska Division of Forestry and Fire Protection (DOF)
conducted forest inventory on state forest classified lands in Matanuska-Susitna (Matsu) Valley
and on general state lands on the Kenai Peninsula in 2014 and 2012, respectively (Figures 2 and
3). It is important to note that the inventory in Matsu Valley and on the Kenai were conducted
before the current spruce beetle outbreak in the region which has caused widespread mortality of
mainly white spruce. Although some of the beetle killed trees might be currently suitable for
biomass, most will likely become too decomposed to harvest in the near future.
Figure 1. A map of Tanana Valley State Forest and State Forest Classified Lands inventoried in 2013.
Kantishna Management Area has since been combined with Fairbanks Management Area and managed by
the Fairbanks Area Office. Map prepared by Elizabeth Fernandez, GIS Analyst.
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Figure 2. A map of state lands inventoried in the Matanuska-Susitna Valley in 2014. Map prepared by
Elizabeth Fernandez, GIS Analyst.
Methods
Inventory data was collected using a stratified random sampling design. The project area was
divided into subpopulations (timber types or strata) to account for variation in species
composition, density, and size class. Each timber type was then treated as a random sample
population. The number of stands sampled within each timber type was based on the variability
encountered in previous forest inventory and timber sale projects. Field measurements were
made in the selected stands to provide estimates of volume. An average of 90 cubic feet of solid
wood per cord was used to estimate biomass availability (Sturgeon 1979. Wood as a Fuel). More
details of inventory methods can be found in inventory reports for each area (Hanson 2013,
Hanson 2012, and Hanson 2013).
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Figure 3. A map of state lands inventoried in the Kenai Peninsula in 2012. Map prepared by Elizabeth
Fernandez, GIS Analyst.
In order to identify the amount of available biomass in accessible stands, 2000’ buffer polygons
were created along the road system in Esri ArcGIS Pro. If a part of the stand falls within the
buffer, then it is included in the accessible stands (Figure 4). GIS Road layers were obtained
from the DOF and Alaska Department of Transportation. The DOF maintains a forestry road
layer for the state forest and forest classified lands. The roads are classified into five status:
active, inactive, closed, proposed, and non-FRPA. Most non-active roads are currently
undrivable by highway vehicles. The status of the forest roads is not completely up to date.
Available biomass estimates were identified for the stands within 2000’ of 1) any road status and
2) active status only.
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a) All stands
b) Accessible stands
Figure 4. Example maps of a) all stands from forest inventory and b) accessible stands using 2000’ road
buffers (this example only includes active forestry roads).
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Results
Tanana Valley State Forest and State Forest Classified Lands
On TVSF and the forest classified lands, 2,152,935 acres was identified as timberland (Table 1)
which is capable of producing timber. About 20% of the timberland is accessible by road (only
including active forestry roads; Table 1). Available biomass in the accessible stands is estimated
at 3.9 million cords or 5.5 million cords if including forestry roads that are not active (Tables 1
and 2). Fairbanks Management Area had the largest area of accessible timberland and biomass
followed by Delta (Table 1 and Figure 5). Most stands in Kantishna Management Area are not
accessible (Table 1 and Figure 5).
Table 1. Timberland area (acres), accessible timberland area (acres and percentage), amount of biomass
(cords), and amount of accessible biomass (cords and percentage) in four management areas in the Tanana
Valley State Forest and the adjacent State Forest Classified Lands.
White spruce sawtimber type provides the largest amount of biomass closely followed by closed
birch type (Table 2). Closed aspen stands also contains a high amount of biomass (Table 2) but
aspen is typically not a preferred species for biomass due to its high moisture content.
Matanuska-Susitna Valley State Forest Classified Lands
A majority of the state lands in Matanuska-Susitna Valley (Matsu Valley) is isolated from the
existing road system (Figure 6). A total of 488,735 acres was identified as timberland, but only
about 2% of the timberland is accessible by road (only including active forestry roads; Table 3).
Available biomass in the accessible stands is estimated at about 174,533 cords or 718,915 cords
if including forestry roads that are not active (Table 4). More than half of the available biomass is
likely birch (Tables 4 and 5). From aerial surveys, the cumulative area impacted by the spruce
beetle outbreak is approximately 2.17 million acres between 2016-2023 (the data have not been
finalized for 2023 and may be subject to minor changes; Jason Moan, personal communication)
and many of large size spruce were killed. As a result, the amount of biomass will likely decline
due to decay.
Management
Area
Timberland
(acre)
Accessible
timberland
(acre)
Accessible
timberland
(%)
Biomass
(cord)
Accessible
biomass
(cord)
Accessible
biomass
(%)
Kantishna 438,235 17,039 4% 4,794,289 82,661 2%
Fairbanks 633,292 200,658 32% 7,773,011 2,315,719 30%
Delta 639,801 153,715 24% 7,083,744 1,198,807 17%
Tok 441,607 59,268 13% 3,379,611 347,538 10%
Total 2,152,935 430,680 20% 23,030,656 3,944,726 17%
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Table 2. Estimates of the amount of biomass available in cords within 2000 feet of any road and active road by strata on the Tanana Valley State
Forest and the adjacent State Forest Classified Lands.
Within 2000' of any road Within 2000’ of active road
Stratum Area (ac) Biomass (cord) Area (ac) Biomass (cord)
White Spruce Sawtimber 28,564 973,728 18,921 653,100
White Spruce Poletimber 21,052 479,808 12,180 284,119
Birch Closed 47,134 887,651 35,760 673,221
Birch Open 4,948 67,035 3,083 41,724
Aspen Closed 25,184 617,312 20,852 512,164
Aspen Open 966 13,105 787 10,494
Birch-Aspen Closed 9,984 197,425 7,894 156,060
Birch-Aspen Open 3,381 53,473 2,626 41,543
White Spruce-Birch Sawtimber 19,069 467,614 14,278 350,113
White Spruce-Birch Poletimber 12,804 212,415 6,748 111,712
White Spruce-Birch-Aspen Sawtimber 8,843 225,758 7,521 193,272
White Spruce-Birch-Aspen Poletimber 14,541 274,128 9,378 177,297
White Spruce-Balsam Poplar 8,494 159,521 5,291 98,779
Black and White Spruce-Birch-Aspen 11,275 166,012 8,969 131,933
White Spruce-Hardwood Reproduction 83,412 423,534 57,828 290,970
Black and White Spruce-Hardwood Reproduction 118,515 281,214 93,195 218,224
TOTAL 418,166 5,499,734 305,312 3,944,726
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Figure 5. A map of accessible and not accessible stands on Tanana Valley State Forest and State Forest Classified Lands. Accessible stands include
all road types.
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Table 3. Timberland area (acres), accessible timberland area (acres and percentage), amount of biomass
(cords), and amount of accessible biomass (cords and percentage) inventoried on the state lands in
Matanuska Susitna Valley and Kenai Peninsula.
Area
Timberland
(acres)
Accessible
timberland
(acre)
Accessible
timberland
(%)
Biomass
(cords)
Accessible
biomass
(cord)
Accessible
biomass
(%)
Matsu Valley 488,735 12,174 2% 6,893,021 174,553 3%
Kenai 46,780 16,223 35% 338,029 132,669 39%
Table 4. Estimates of the amount of biomass in cords within 2000 feet of any road and active road by
strata on the State Forest Classified Lands in Matanuska-Susitna Valley.
Table 5. Brief description of each stratum for Matsu Inventory data.
Stratum Description
Mixed Poletimber Closed Primarily birch
Mixed Poletimber Open Even mix of white spruce and birch with a minor amount of black
spruce
Hardwood Closed Birch 45%, white spruce 23%, balsam poplar 11%
Hardwood Open About 2/3 birch and 1/3 white spruce
Mixed Spruce/Hardwood
Closed
Even mix of white spruce and birch with a minor amount of black
spruce
Mixed Spruce/Hardwood
Open
Even mix of white spruce and birch with a minor amount of black
spruce
Mixed Reproduction Nearly half is black spruce with even mix of balsam poplar, birch
and white spruce
Within 2000' of any road Within 2000' of active road
Stratum
Area
(acres)
Biomass
(cord)
Area
(acres)
Biomass
(cord)
Mixed Poletimber Closed 7,487 136,761 3,182 58,130
Mixed Poletimber Open 5,217 60,802 2,230 25,987
Hardwood Closed 7,629 193,263 860 21,794
Hardwood Open 6,200 75,299 624 7,574
Mixed Spruce/Hardwood Closed 4,605 73,367 1,615 25,736
Mixed Spruce/Hardwood Open 9,206 126,837 1,126 15,513
Mixed Reproduction 6,732 52,587 2,537 19,817
TOTAL 47,075 718,915 12,174 174,553
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Figure 6. A map of accessible and not accessible stands on State Lands in Matanuska Susitna Valley.
Accessible stands include all road types.
Kenai Peninsula State Forest Classified Lands
On state lands on Kenai Peninsula, 46,780 acres was identified as timberland, and about 35% of
the timberland is accessible by road (only including active forestry roads). State lands, regardless
of accessibility, are scattered on the peninsula (Figure 7). Available biomass in the accessible
stands is estimated at about 132,669 cords or 177,547 cords if including forestry roads that are
not active (Table 6). It is important to note that about half of the biomass is on the stands heavily
affected by spruce beetle where most sawlogs were dead as of 2011. These dead trees might have
been suitable for fuelwood and biomass in 2011, but the amount of usable wood might have
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declined due to decay. In addition, the most recent spruce beetle outbreak since 2016 likely killed
more trees, resulting in fewer live spruce.
Figure 7. A map of accessible and not accessible stands on State Lands on Kenai Peninsula. Accessible
stands include all road types.
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Table 6. Estimates of the amount of biomass in cords within 2000 feet of any road and active road by strata on the State Lands on Kenai
Peninsula.
Within 2000' of any road Within 2000' of active road
Stratum Area (acres) Biomass (cord) Area (acres) Biomass (cord)
Needleleaf: dead white or Sitka spruce 9,530 78,993 9,196 76,225
Needleleaf: live white or Sitka spruce, pole 364 648 356 632
Needleleaf: live white or Sitka spruce, seedlings 3,121 3,815 1,681 2,054
Needleleaf: black spruce, pole size or larger 1,596 3,867 675 1,634
Needleleaf: mountain hemlock 559 18,810 559 18,810
Broadleaf: pole size or larger 2,572 14,089 604 3,307
Mixed forest: broadleaf dominating 1,726 20,076 1,726 20,076
Mixed forest: dead needleleaf dominating 5,355 37,249 1,428 9,931
TOTAL 24,824 177,547 16,223 132,669
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References
Hanson, D. 2012. Forest Resources on State Lands in the Kenai Peninsula. State of Alaska
Department of Natural Resources, Division of Forestry.
Hanson, D. 2013. Timber Inventory on State Forest Lands in the Tanana Valley. State of Alaska
Department of Natural Resources, Division of Forestry.
Hanson, D. 2014. Forest Resources on State Lands in the Susitna Valley. State of Alaska
Department of Natural Resources, Division of Forestry.