Progress 06/01/09 to 06/30/11
Outputs
OUTPUTS: We conducted this analysis of direct field measurements to update the estimators of wood in piled logging residue and biomass supply studies based on those estimators. Specifically, the purpose of this project was to quantify (1) the production of logging residue in Clallam, Jefferson, Kitsap, Mason, and Grays Harbor Counties for 2008 and 2009; (2) the volume of solid wood contained in a slash pile; and (3) the total supply and average price of biomass deliverable to the cities of Forks, Port Angeles, Port Townsend, Shelton, and Aberdeen, Washington. PRODUCTION: The study reviewed the state of Washington's 1,400+ Forest Practice Applications (FPAs) on the Olympic and Kitsap Peninsulas for calendar years 2008 and 2009. The set was narrowed to 975 FPAs -- encompassing 66,729 ac by excluding units of less than 15 ac as well as single-tree, right-of-way, and salvage operations. As federal and tribal timber harvests do not require FPAs, they too were excluded. Applications were stratified by four factors thought to be associated with distinct production rates: forest location (east/west side of the Olympic Peninsula), harvest intensity (clearcut/thinning), ownership type (public/nonpublic), and harvest method (ground/cable/mixed). To capture mean residue production within 15 percent four times out of five, the desired sample size of 86 harvest units was allocated among strata according to proportion of harvest activity. In total, 511 transects were installed to sample scattered residues on 53 harvest units; all 3,075 slash piles were measured on 55 harvest units. VOLUME-TO-WEIGHT RATIOS: The existing ratio estimator for volume-to-weight dates from 30 years ago and does not represent current harvest methods or forest conditions. An experiment was conducted to update the volume-to-weight ratio estimator: each of 20 selected slash piles was measured for gross volume before and after processing; five samples were drawn from each processed hog-fuel pile for further laboratory analyses to determine moisture content, compaction, and specific gravity. SUPPLY CURVES: Data from the Washington State Forestland Database were used to identify timber-producing parcels and stratify them directly for location and ownership type. Parcels were aggregated in 10-minute intervals based on delivery time to a given delivery center. Harvest type and method were imposed on the aggregated interval acreage in the proportions indicated by the production study. Base rates of $35 per BDT for in-woods recovery and $65 per hour for transportation costs were assumed; both rates are subject to a fuel surcharge assessed at a rate of 1 percent for every 10 cent increase in diesel prices. PARTICIPANTS: The research team for the production study and updated volume-to-weight ratios included: 1. Jason C. Cross, Research Coordinator, Olympic Natural Resources Center, University of Washington, College of the Environment, School of Forest and Environmental Sciences. 2. Eric C. Turnblom, Associate Professor, University of Washington, College of the Environment, School of Environmental and Forest Sciences. 3. John Calhoun, former director, Olympic Natural Resources Center, University of Washington, College of the Environment, School of Forest and Environmental Sciences. The research team for the supply curves included: 1. Gregory J. Ettl, director of the Center for Sustainable Forestry at Pack Forest and Professor, University of Washington, College of the Environment, School of Environmental and Forest Sciences. 2. Jeff Comnick, research scientist, Olympic Natural Resources Center, University of Washington, College of the Environment, School of Forest and Environmental Sciences. Other participants: 1. Jeff McGinley of Pacific Forest Management in Forks, Washington, helped secure landowners' permissions to access harvest units and collect field data. 2. Reed Wendel, Aaron Brooks, and Scott Jamieson, all from Pacific Forest Management, collected field data. 3. Rebecca Gentry of Olympic Natural Resources Center conducted the laboratory analyses of hog fuel samples. 4. Updated volume-to-weight ratios would not have been possible without the cooperation of Bill Hermann of Hermann Brothers Logging in Port Angeles, Washington. His willingness to alter production methods allowed for measurements that could not otherwise be taken. 5. George Cave of Port Townsend Paper provided insight into the methods for developing supply curves that tempered a desire for precision with operational realities. Sponsors: This work was made possible with funding from the Restoration Silviculture Initiative -- a partnership between the University of Washington's Olympic Natural Resources Center and the U.S. Forest Service's Pacific Northwest Research Station. The expanded scope of the analysis was made possible by additional funding from the Northwest Clean Energy Application Center and Washington State University. TARGET AUDIENCES: Target audiences included the US Forest Service, timber harvesters, land managers, local and state governments, the renewable fuels industry, researchers, educators, students, and the general public. PROJECT MODIFICATIONS: We expanded the initial scope of analysis to include supply curves, residue ratios, and biomass assessment.
Impacts
PRODUCTION: Eighty-nine percent of timber harvest was located on the west side of the Olympic Peninsula, and clearcuts accounted for 88 percent of harvest intensity. A Type II analysis of variance (ANOVA) on transect data found ownership to be a factor associated with different production rates -- 1,588 cubic feet/ac on public lands versus 1,155 cubic feet/ac on nonpublic land. A similar test on piled residue data resulted in two distinct production groupings: "high" production yielded an average 325 cubic feet/ac; "low" production yielded 65 cubic feet/ac. Both groups consisted of strata with each level of forest location, harvest intensity, and ownership type. Harvest method was not identified as a factor associated with different production levels. Annualized harvest rates and volumes (FPAs) with residue production attributes and ratios are summarized below: 1. FPA acreage: 33,364 ac 2. Harvested timber volume: 885 million board feet 3. Transected residues: 1,292 cubic feet/ac 4. Pile residues: 307 cubic feet/ac 5. Total residues: 1,599 cubic feet/ac 6. Bone dry tons (BDT) of residue per acre: 19 7. Ratio of BDT to harvested thousand board feet: 3:4. VOLUME-TO-WEIGHT RATIOS: Results indicated that the volume of processed hog fuel is a function of the square root of the original slash pile volume; and the solid wood volume of a hog-fuel pile is approximately 38 percent of its volume. The green density of the wood component was quantified at 18.72 lb/cubic foot; bone dry density was 9.05 lb/cubic foot. We derived a formula relating mass of wood in a pile to the gross biomass available. SUPPLY CURVES: The supply curves assembled with the production and cost values indicate Forks to be the most competitive delivery site for quantities up to 50,000 BDTs (MBDTs). Overall, Aberdeen had access to the greatest annual quantity of hog fuel (600 MBDT/year), while hog fuel available for delivery to Shelton had the lowest average unit price ($53.26/BDT). Port Angeles and Port Townsend have access to decidedly smaller quantities at the highest average prices. Delivery centers are ranked from the highest to lowest annual quantity of hog fuel deliverable at an average unit price of $50/BDT: Aberdeen (410 MBDT/Y), Shelton (320 MBDT/Y), Forks (280 MBDT/Y), Port Angeles (110 MBDT/Y), and Port Townsend (100 MBDT/Y).
Publications
- Cross, J. C., Turnblom, E. C., and Ettl, G. L. 2013. Biomass Production on the Olympic and Kitsap Peninsulas, Washington: Updated Logging Residue Ratios, Slash Pile Volume-to-Weight Ratios, and Supply Curves for Selected Locations. United States Forest Service Pacific Northwest Research Station General Technical Report, PNW-GTR-872, January 2013. Available online at: http://www.fs.fed.us/pnw/publications/gtrs.shtml, link verified 2/6/2013.
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