Effects of Disturbance on the Terrestrial Carbon Budget of a Central Appalachian Forest

Seventy six percent of the land area in the state of West Virginia is forested with timber quality trees that are managed in a variety of ways. The objective of our study was to determine how harvest events affect forest productivity using dendrochronological and ecological modeling techniques. Watersheds in the Fernow Experimental Forest (Parsons, WV) served as model systems to explore the effects of land management decisions on productivity of hardwood forests. We compared the productivity of a 100 year old naturally regenerated forest with a forest that was clear-cut in the 1960s. We estimated annual aboveground net primary productivity (ANPP), aboveground biomass, and litterfall in these watersheds using annual woody biomass increments and litterfall collection data. Modeled estimates of ecosystem productivity were generated using the PnET-CN model that was parameterized with site-specific foliar characteristics and climate data. Modeled estimates of the mature 100 year old forest corresponded closely with dendrochronological measurements of productivity (~9.8 % difference), but model estimates of forest productivity in the clear-cut forest varied distinctly from measured productivity. The chronosequence of modeled productivity following the clear-cut event rebounded much more quickly to a steady-state relative to the dendrochronological record. Dendrochronological estimates suggest that ANPP in the clear-cut watershed surpassed ANPP in the older watershed after 15 years of regeneration and continued to increase without decline even after 30 years. Further evaluation of changes in productivity that result from a variety of harvesting events should illuminate the intrinsic effects of different land management decisions on forest carbon budgets. Large-scale carbon flux projections may eventually be modified according to findings from these experimental approaches.