Loading...
HomeMy WebLinkAboutUpper Kobuk Valley Wood Biomass Study (1) 2010 UPPER KOBUK VALLEY WOOD BIOMASS STUDY Prepared for: Alaska Wood Energy Associates by Forest & Land Management, Inc. P.O. Box 110149 Anchorage, Alaska 99511-0149 September 2010 1 Table of Contents EXECUTIVE SUMMARY ............................................................................................................ 2 SETTING ........................................................................................................................................ 3 PURPOSE ....................................................................................................................................... 3 METHODOLOGY ......................................................................................................................... 3 DISCUSSION AND RESULTS ..................................................................................................... 4 Trees, Volumes, and Suitability for Biomass ............................................................................. 4 Forest Succession and implications for future management ....................................................... 5 Potential Wood Supply Characteristics of Ambler, Shungnak, and Kobuk ............................. 10 Ambler: ................................................................................................................................. 10 Shungnak: ............................................................................................................................. 12 Kobuk:................................................................................................................................... 12 Considerations for harvesting ................................................................................................... 14 Planning Harvest Areas and Managing For Regeneration: ................................................... 14 Ownership Of Trees and Logs: ............................................................................................. 14 Log delivery, handling, and storage: ..................................................................................... 14 Forest Practices Regulations: ................................................................................................ 15 Harvesting and Transport Equipment: .................................................................................. 15 Personnel: .............................................................................................................................. 15 FEASIBILITY ASSUMPTIONS: ................................................................................................ 16 CONCLUSION ............................................................................................................................. 16 REFERENCES ............................................................................................................................. 17 ACKNOWLEGEMENTS ............................................................................................................. 17 2 Upper Kobuk Valley Wood Biomass Study EXECUTIVE SUMMARY The remote location of Ambler, Shungnak, and Kobuk results in a high cost for diesel oil and gasoline, which must often be flown in by air tanker. These communities rely on diesel oil for electrical power generation and heating of community buildings. Firewood is used in many homes to supplement diesel oil for heating. The extreme climatic conditions dictate the need for reliable electric power and heat. Three species of hardwood (balsam poplar, aspen, and birch) and two species of conifer (white spruce and black spruce) are indigenous to the region, and are available for use as wood biomass fuel for electrical power generation and heating. The implementation of wood biomass power projects in this area must be: 1) accomplished at an appropriate scale, preferably with an initial pilot project, and 2) subject to detailed management and accountability from the first step of harvest planning through the process of managing and maintaining the electrical generation and heating facilities. 3 SETTING The villages of Ambler, Shungnak, and Kobuk are located in the upper Kobuk River valley, above the Arctic Circle, and at the northwestern edge of the range of white spruce (Picea glauca) and black spruce (Picea mariana), as well as aspen (Populus tremuloides), cottonwood (Populus balsamifera) and birch (Betula papyrifera). The spruces are the only conifer tree species in the area, but in addition to aspen, cottonwood, and birch (the largest hardwoods) there are a variety of willows and alders that grow principally in wet areas such as flood plains and braided stream channels. This area of Alaska is remote, the principle means of transportation to reach these communities is by small local airline or charter aircraft from Kotzebue, approximately 140 miles due West. In years when river levels are adequate, occasional barge transportation is available to carry supplies such as construction materials or fuel to these communities. There is no road infrastructure connecting these communities, however in the summer boat travel on the river is possible, and in the winter ATV, snow machine, and vehicle travel over the ice on the river is possible. PURPOSE This purpose of this report is to suggest a conservative amount of wood that can be harvested sustainably for biomass within 15 miles of Ambler and Kobuk. Shungnak is approximately 7 miles from Kobuk, and is connected by an electrical transmission line with Kobuk; therefore it is within the radius of Kobuk. METHODOLOGY Field inspection included viewing areas along the river and adjacent to the villages while flying into and between the villages; visual observation while traveling on existing ATV trails in the vicinity of Ambler and Kobuk; and actual measurements of spruce and aspen trees in plots. The plots were randomly selected, however due to the size of the geographic area being studied, sampling was not intended to provide statistically significant results, but rather to support a conservative estimate of potential biomass availability. Ortho imagery and Landfire vegetation classes from Landfire maps (reference) were used to assist in identification of areas with potential heavy concentrations of spruce, aspen and cottonwood. To augment the field inspection, several sources of published information that are believed to contain appropriate information of tree volume and volume per acre were reviewed, and the relevant information utilized in developing the estimates reported herein. 4 DISCUSSION AND RESULTS Trees, Volumes, and Suitability for Biomass Trees in this area, due to geography, climate, and geology, are shorter, smaller diameter (at breast height- "dbh") and generally there are fewer stems per acre. Trees at the extremes of their range grow slower; the increment of wood that they add each year is less than in more favorable conditions - when looking at growth rings they may be the thickness of a sheet of paper, rather than several tenths of an inch, and annual height growth may be in terms of inches, rather than feet. No distinction is made in this report between black and white spruce, as they have similar qualities for the purpose as fuel wood. Cubic Feet Tons Cubic Feet Tons Cubic Feet Tons Total Tons per acre per acre per acre per acre per acre per acre Cubic Feet per acre Spruce Spruce Aspen Aspen Birch Birch per acre Total 210 4 860 18 0 0 1092 22 0 0 1624 35 0 0 1659 35 125 2 0 0 0 0 127 2 0 0 612 13 0 0 625 13 976 17 0 0 0 0 992 17 994 17 0 0 105 3 1116 20 439 7 23 0 0 0 470 8 1019 17 312 7 0 0 1355 24 421 7 0 0 32 1 460 8 Average 465 8 381 8 15 0 877 16 Table 1: Tabular results of sample plots. Table 1 displays the results of the randomly selected plots that are used to generate an empirical basis for estimates of green tons per acre of biomass available. The above data is based on total tree height, and indicates the total weight in the trunk of the tree, it does not include branches. The most frequent diameter at breast height (4.5 inches above the ground) of the spruce and aspen was six inches. Tree height for six-inch aspen and spruce ranged from 36 feet for aspen to 45 for spruce. The following table applies average tons per acre to each of the vegetative cover types from the Landfire map. An adjustment factor was applied to each cover type to account for volumes that are not recoverable for any number of reasons, including terrain and accessibility. The result is the estimated tons of biomass by cover type area that could potentially be harvested. 5 Ambler Total Cover Type Acres Factor Tons/Acre Tons Tree Canopy >= 10 and < 25% 57,634 0.5 8 230,536 Tree Canopy >= 25 and < 60% 86,747 0.75 16 1,040,964 Tree Canopy >= 60 and <= 100% 1,756 0.5 22 19,316 Kobuk-Shungnak Total Cover Type Acres Factor Tons/Acre Tons Tree Canopy >= 10 and < 25% 52,935 0.5 8 211,740 Tree Canopy >= 25 and < 60% 82,766 0.75 16 993,192 Tree Canopy >= 60 and <= 100% 2,900 0.5 22 31,900 Table 2: Cover type acres and total tons results. Table 2 reflects information gathered for spruce and aspen. Birch was a minor component in the stand, and although pure birch stands exist, they are infrequent. Balsam poplar is abundant along the riverbanks, and braided stream channels. Although it was not included in the sampling, it is an obvious source of fuel; particularly for harvest when the rivers are frozen. Wood has traditionally been used as a fuel for wood stoves. In Ambler, spruce firewood has been harvested from areas that burned in the immediate vicinity. Additionally, along the roads and trails evidence of firewood harvest, in the form of the remaining stumps, was frequent. In Kobuk, the same was true. It was reported that in the winter individuals harvest firewood in the form of logs and haul them to the village on a sled pulled by a snow machine, either for personal use or for sale. In Kobuk, a sled load of firewood sells for $70.00. Such a sled load is ten to twelve logs 5 to 6 inches in diameter on the small end, about 12 to 14 feet long. This calculates to about 26 cubic feet of solid wood per sled load (probably between 850 and 1,000 pounds per sled load!) For firewood, the preferred species are birch and spruce, due to their relative BTU factors, however for a biomass heating system, aspen and cottonwood (balsam poplar) are suitable species. Forest Succession and implications for future management Forest fire is a dominant factor in determining the composition of tree vegetation on the landscape in interior Alaska. Mature white and black spruce stands, due to their inherent combustibility and the presence of fuel from the surface of the ground to the branches of the trees are susceptible to both man-caused and lightning caused fires. These fires often kill the 6 standing trees, leaving standing dry material - as well as consuming the organic layer on the ground and thus resulting in a warming of the soil for the next stage of successional vegetation. Following a fire, aspen and birch are the pioneer species that regenerate along with the herb and shrub groundcover. The hardwoods will dominate the new forest, with some spruce regeneration in the understory. As the trees advance in age, hardwoods may dominate the forest, or it may become a mixed hardwood and conifer forest. As the illustration below suggests, at 50 to 150 years, spruce and hardwood reach biological maturity. Figure 1: Succession of plant growth from fire (or disturbance) to mature forest over time. Following a fire, aspen and birch are the pioneer species that regenerate along with the herb and shrub groundcover. The hardwoods will dominate the new forest, with some spruce regeneration in the understory. As the trees advance in age, the forest may become dominated by hardwoods, or it may become a mixed hardwood and conifer forest. As the illustration above suggests, at 50 to 150 years, spruce and hardwood reach biological maturity. Depending on the intensity of harvest and the amount of ground disturbance, it is highly likely that management based on natural regeneration will result in predominately aspen, with some birch trees. In order to manage for spruce, it most likely will be necessary to hand plant seedlings. Although all trees are relatively slow growing in this region, aspen and cottonwood appear to have higher growth rates than spruce; therefore targeting these species for wood biomass management may be desirable. Various management techniques can be employed to determine species composition, increase the rate of growth and the size of the resulting trees; these include planting and stocking control (thinning) to reduce competition between individual trees. 7 Figure 2: Aspen (light green) and spruce (dark green) stands near Ambler In the vicinity of Ambler, and particularly to the west of Ambler, the impact of the region's fire history is evident. The Aspen stands in Figure 2 are typical of fire origin stands in the area. The preferred source of firewood for the area in the past was white spruce in the area northwest of Ambler that reportedly burned in about 1971. It is unclear what time frame is normal in this region for the transition from fire-killed spruce to a fully stocked forest of aspen trees, however it is likely that it is about 30 years. It would follow then that in order to shorten the time between fire or harvest and another harvest, it would be necessary to either plant or otherwise facilitate the establishment of new seedlings as soon as possible. Where there are mature forests of white spruce trees as shown in Figure 3, they are generally at higher elevations on well drained soils. Harvest planning should consider scheduling mature spruce for early harvest due to the potential for fire, and the efficiencies associated with harvesting larger trees from areas with higher volume density. Planning should not be predicated on managing spruce, due to its relatively slower growth rate; however on areas with suitable soil conditions, consideration should be given to planting white spruce seedlings in the spring or fall immediately after harvest. 8 Figure 3: Typical mature white spruce At lower elevations, particularly in areas of tundra, and on sand dunes, black spruce trees and an occasional birch tree grow with characteristic wide spacing between trees and dense ground cover of various brush species. Black spruce is a relatively slow growing species (compared to white spruce), and seldom attains the same size as a typical white spruce tree in this area. Figure 4: Typical black spruce 9 Figure 5: Black spruce with birch Figure 6: Aspen forest, typical of post fire succession. In order to achieve a sustainable supply of wood biomass, it will be necessary to intensively manage the regrowth. This will be a long range process, because with relatively low growth rates, it may take 35 to 40 years to produce trees large enough for economic biomass harvest. Balsam poplar (cottonwood) grows along river banks and on flood plains in the region has the fastest growth rate of the species which are common to the area. Additionally, it is possible to use cuttings from cottonwood for planting the next crop of trees in areas that are suitable for growing cottonwood as a crop. The focus of managing for biomass should be on cottonwood, aspen and birch, due to their growth rates, and suitability for growth on much of the area. 10 The options for regeneration of cottonwood, aspen and birch include planting using either seedlings or cuttings, or relying on natural seeding. The objective of planting is to achieve faster establishment of the next crop of trees, which will presumably be ahead of natural seedlings or stump sprouts. It will be necessary to insure establishment of the next crop in the planting season following harvest. At approximately 15 years after establishment of the new crop of trees, it may be desirable to perform a thinning operation that would remove smaller trees, around selected crop trees. The objective will be to allow every chance for trees to achieve at least a six inch diameter at breast height - in about the same time frame (within 40 years from establishment). Potential Wood Supply Characteristics of Ambler, Shungnak, and Kobuk Ambler: Ambler is situated on the north bank of the Kobuk River, which at least in the winter can provide access to cottonwood growing near the banks of the river (considering the Forest Practices Act requirements for un-cut riparian buffers). A gravel road goes north from Ambler to the airport and branches to the west to the municipal solid waste facility. Trails suitable for ATV's and snow machines branch off from the airport and the road to the west. Where they are located on relatively solid soils the major trails have the potential for being upgraded to roads with gravel surface and water crossing structures such as bridges or culverts,. To the northwest there is an area that burned in 1971, and to the northeast there is an area that burned in 1985; these areas should be evaluated as potentially the first sources of wood biomass, and for the initiation of the management regime to control stocking and improve yields per acre. A third area, which is approximately 6 miles due north of Ambler has higher volume white spruce timber stands that could be accessed for planned harvest and reforestation. The above areas are shown on the "Ambler Vicinity LandFire" map on the following page. The fire areas are identified in the legend by year, and the third area is depicted by the tree canopy cover symbols in dark blue and red. Annual Volume Estimated Average Estimated Total Acres AMBLER Wood Biomass Wood Biomass Acres per To Be Managed (Green Tons) Green Tons per acre year Over 40 Years 850 16 53 2,125 Table 3: Summary of wood biomass volumes and acres needed each year. With intense silvicultural management such as stocking control (thinning) and planting after harvest, it should be possible to either increase the annual volume of wood biomass harvested from the same acres, or reduce the number of total acres. 12 Shungnak: Shungnak and Kobuk are linked by an electrical power line, with the power generation facility located in Shungnak. This electrical power supply arrangement has two consequences: 1) the opportunity for savings due to fuel used in generators is absent in Kobuk, 2) the proximity of Kobuk to the source of wood biomass is more favorable than that of Shungnak. Shungnak is located on the west bank of the Kobuk River, and is surrounded by tundra and relatively flat terrain with little tree type vegetation except along the river channel. In the immediate vicinity of Shungnak, cottonwood harvested in the vicinity of river banks (considering the Forest Practices Act requirements for un-cut riparian buffers) is the most accessible source of wood biomass. The "Kobuk-Shungnak Vicinity LandFire" map on the following page shows the areas with the greatest potential for wood biomass as the areas depicted in dark blue. Annual Volume Estimated Average Estimated Total Acres SHUNGNAK Wood Biomass Wood Biomass Acres per To Be Managed (Green Tons) Green Tons per acre year Over 40 Years 500 16 31 1,250 Table 4: Summary of wood biomass volumes and acres needed each year. Kobuk: Kobuk is located on the north bank of the Kobuk River, and is surrounded relatively flat terrain and tundra. A gravel road goes north out of Kobuk 2.5 miles to an airstrip and mining camp at Dahl Creek, and continues northwest to Bornite, a total of about 9 miles from Kobuk. This road system provides good access to areas with spruce, and trails east and west of Dahl Creek can be utilized to access aspen, birch and cottonwood. East and west of Dahl Creek the topography rises gently, with drier ground and trees, which will be suitable for construction of gravel roads directly through timbered areas. The "Kobuk-Shungnak Vicinity LandFire" map on the following page shows the areas with the greatest potential for wood biomass as the areas depicted in dark blue and red. Annual Volume Estimated Average Estimated Total Acres KOBUK Wood Biomass Wood Biomass Acres per To Be Managed (Green Tons) Green Tons per acre year Over 40 Years 350 16 22 875 Table 5: Summary of wood biomass volumes and acres needed each year. 14 Considerations for harvesting Planning Harvest Areas and Managing For Regeneration: Preparation of a plan and enforcing implementation of that plan will be imperative for the success of a wood biomass fuel project in this area. The management plan must: 1) identify areas for harvest by year for the life of the project, 2) identify routes or trails for transport of harvested materials to the biomass heating/power facility, 3) identify roads that need to be constructed as well as the construction standards, 4) specify harvest system (clear-cut or selective cut with tree marking), 5) specify regeneration system (natural regeneration or planting), and 6) schedule timber stand improvement activities to be implemented during the time from regeneration establishment to harvest. Each year the area to be harvested should be identified with boundary marking ribbon that will be visible when the trees and ground are covered with snow. The purpose of marking these areas is to make sure that the management scheme, whether clear cut or selectively cut is followed to facilitate the regeneration and future forest management of the specific area. Similarly, trails for transport of the harvested products must be marked to insure compliance with the requirement for minimal disturbance to sensitive ground conditions and insure adequate bridges or culverts are maintained over stream crossings. Areas planned for intensive management should be far enough away from the community to avoid any conflicts with local uses of lands in the immediate vicinity, such as subsistence uses. Ownership Of Trees and Logs: Tracking of the origin of logs delivered to the community biomass fueled heating facility is essential to preventing trespass on allotments or other private lands where harvesting for the community biomass fueled heating facility is not authorized. It is likely that allotment owners will want to become producers of fuel logs, so provision should be made to verify the ownership and authorization to harvest from private lands. Log delivery, handling, and storage: Logs will generally be paid for upon delivery to a fenced, secure yard area in the proximity of the power facility. If payment for the logs is based on weight, a certified scale with weight certificate printout capability will be necessary on site. Alternatively, logs can be measured and "scaled" on site by a trained responsible employee, with documentation and payment receipts prepared at the time of delivery. Sufficient space should be available to store logs in "decks" so that they will be able to "dry out" to reduce the moisture content from approximately 55% green, to 45% moisture content for fuel. For planning purposes, the target should be to have a year's supply of wood in decks and drying at all times. 15 Forest Practices Regulations: For the purposes of Forest Practices Regulations, this area is in Region III. A number of regulations apply to the harvest of forest products and related operations such as road building and maintenance. These regulations apply to any landowner with a total ownership of 160 acres or more who is conducting a commercial operation on 40 acres or more, or a commercial operation that intersects, encompasses, or borders on surface waters or a riparian area. Planned harvest areas must be notified to the State Division of Forestry at least 30 days in advance of the start of road construction or harvest operations. Harvest areas, roads, and riparian buffers must be marked on the ground for review by a Division of Forestry representative. Riparian protection standards prohibit harvest of timber within 66 feet of a Type III-A water body; and within 33 feet of a Type III-B water body. A Type III-A water body is a (A) nonglacial high value resident fish water body greater than three feet in width at the ordinary high water mark; (B) nonglacial anadromous water body; or (C) backwater slough. A Type III-B water body is a glacial high value resident fish water body or a glacial anadromous water body, and does not include a backwater slough. Harvesting and Transport Equipment: Due to the small size and spacing of the trees, it will be necessary to innovate appropriate machinery for harvesting. It is likely that other boreal regions such as Canada or Scandinavia have developed equipment suited for working in harsh climatic conditions to harvest small trees, and these should be investigated. The type of equipment visualized for this area are wheeled or track vehicles that would create minimal disturbance to tundra and could travel over snow, similar to larger ATV's and snowmobiles. These machines would tow a trailer or sled with suitable low ground pressure wheels or runners. Falling the trees (cutting them down), limbing and bucking (cutting off the branches and cutting the logs to the desired length) can be accomplished using chain saws. Loading the logs onto a sled or trailer can either be done by hand, or with a small "bobcat" type machine equipped with lifting forks and tracks. Another consideration is the lack of roads, and the importance of minimizing disturbance to the tundra while transporting logs. Planned trails should be located and marked from local roads to harvest areas. Directing traffic through the least sensitive areas and over more solid ground will help reduce adverse impacts, as well as avoid the cost of building roads, where feasible. Personnel: Along with scaling the size of equipment to the size and location of the trees, it is important to design the harvesting, delivery, and operation of biomass harvesting to be compatible with the subsistence lifestyle of the village. This means scheduling harvesting around traditional work hours, hunting, fishing and other subsistence activities. Further, planning for timber harvest should avoid conflict with or provide for firewood harvest for local residents to insure that homeowners will not be deprived of firewood or priced out of affordable firewood for heating and cooking. 16 Safety training should be provided and required of all workers involved in the harvesting, transport or handling of biomass fuel wood. This training should include topics such as safe equipment operation, cold weather, hypothermia and frostbite precautions, drug and alcohol subjects, and identification of authorized areas within which harvest can occur. FEASIBILITY ASSUMPTIONS: 1) The availability of wood biomass from existing aspen, cottonwood, or birch timber stands with an average of 16 tons per acre. 2) With intensive management of new growth aspen, cottonwood, and birch timber stands; a projected yield of 35 tons per acre with a 40 year rotation. 3) The availability of people to manage and carry out the harvest and intensive management activities over the full rotation period. 4) Petroleum fuel costs in each of the villages will continue to increase above $8.00 per gallon. 5) Wood biomass fuel requirements by village will start at: Ambler - 850 green tons per year Shungnak - 500 green tons per year Kobuk - 350 green tons per year 6) Delivered cost per ton of wood will be less than $250.00 per ton - including costs of implementing intensive forest management, harvest, and delivery. CONCLUSION The reality is that in areas near the Arctic Circle, trees are relatively small but the density of biomass per acre, and the potential annual growth of wood biomass per acre are within the realm of feasibility for the development of wood biomass fueled heat generating systems. With the development of a planned management system for the growth of harvestable biomass, the development of appropriate harvesting and delivery systems, and advances in the technology of converting wood biomass to either heat or electricity; there is clearly the potential for substituting wood biomass for petroleum products for power production in rural Alaska. The key to the success of a biomass power project in this area is depends on planning and design of the entire operation at the appropriate scale. For successful project development; 1) harvesting by conventional means would not be cost effective - therefore equipment designed for use in small log harvesting in winter and in a tundra environment will be essential, 2) management of harvest regimes to insure sustainability will necessitate detailed planning and execution due to the long span of time between harvest and regrowth of a new stand of trees, 3) large scale utilization of only one species of wood to support a biomass energy project is probably not realistic, cottonwood and aspen should be the planned primary species, with the ability to utilize birch and spruce as these species are available. 17 REFERENCES Fresco, Nancy, and Chapin III, F. Stuart, USDA Forest Service, Pacific Northwest Research Station, Research Paper PNW-RP-579: Assessing the Potential for Conversion to Biomass Fuels in Interior Alaska, June 2009. Haack, Paul M., USDA. Forest Service, Northern Forest Experiment Station, Juneau, Alaska Research Note NOR-3: AERIAL PHOTO VOLUME TABLES FOR INTERIOR ALASKA TREE SPECIES, May 1963. Haack, Paul M., USDA. Forest Service, Northern Forest Experiment Station, Juneau, Alaska Research Note NOR-5: VOLUME TABLES FOR TREES OF INTERIOR ALASKA, September 1963. Haack, Paul M. and Robert A. Gregory, USDA. Forest Service, Northern Forest Experiment Station, Juneau, Alaska Research Note NOR-6: EQUATIONS AND TABLES FOR ESTIMATING CUBIC-FOOT VOLUME OF INTERIOR ALASKA TREE SPECIES, May 1964. LANDFIRE Team, USGS, FireLab USDA Forest Service, The Nature Conservancy; LANDFIRE (Landscape Fire and Resource Management Planning Tools Project), 2009. Wilson, Pamela L., Funck, James W., and Avery, Robert B., USDA Forest Service, Pacific Northwest Research Station, General Technical Report PNW-GTR-810: Fuelwood Characteristics of Northwestern Conifers and Hardwoods (Updated), April 2010. USDA Forest Service, National Technology Development Program, 2400 - Forest Management, WOODY BIOMASS UTILIZATION DESK GUIDE, September 2007. USDI, US Fish & Wildlife Service, Fire Information & Resource Education, Poster: Fire's Natural Role In Alaska, undated. ACKNOWLEGEMENTS Cartography: Paula Hanson, WH Pacific Project Management and logistics: Dr. William Wall, Sustainability, Inc. Report Author and production: Clare E. Doig, CF, ACF, Forest & Land Management, Inc.