Carrie M. Lee1, Daniel Vogt1, Robert Edmonds1, and Richard Bigley2. (1) University of Washington, College of Forest Resources, Box 352100, Seattle, WA 98195, (2) Washington Dept of Natural Resources, PO Box 47014, Olympia, WA 98504-7014
There is strong consensus among the scientific community that levels of atmospheric carbon dioxide are rising rapidly and will significantly affect global climate. Means to reduce emissions through renewable energy sources and increased carbon sequestration will aid in mitigating rising greenhouse gas levels. Management of forests which, account for 90% of the annual carbon flux of terrestrial ecosystems, provides the greatest potential for increasing terrestrial carbon storage. However, there has been little agreement over the best strategy. This study examined how thinning and woody biomass utilization can be coupled as a forest management tool to maintain carbon stored in forest stands while decreasing net carbon emissions through the generation of a renewable energy source. Measurements of tree growth and biomass, coarse and fine woody debris, and total soil carbon and nitrogen were used to evaluate the impact of thinning and woody biomass utilization on site and soil productivity. Data measurements were conducted on a 4 x 4 matrix of treatments established in 1995 at the Sappho Long-Term Ecosystem Productivity Site (LTEP) including a no-cut control and late-seral thinned treatments with high, medium, and low levels of woody biomass removal. The Sappho LTEP is located in Sappho, WA on the Olympic Peninsula in a ~60 yr. old regenerated forest stand of primarily western hemlock (Tsuga heterophylla) and Douglas-fir (Pseudotsuga menziesii). Long-term site and soil productivity was evaluated by comparing data between treatments and through time using pretreatment data collected before 1995 by LTEP researchers. This study evaluated the potential to offset carbon dioxide emissions through forest management, while providing the added environmental and societal values of decreased wildfire and insect outbreak risk and increased economic opportunity for rural communities.