Use of state-and-transition simulation modeling in National Forest planning in the Pacific Northwest, U.S.A

Abstract

Effective national forest planning depends on scientifically sound analyses of land management alternatives relative to desired future conditions and environmental effects. The USDA Forest Service Pacific Northwest Region is currently using state-and-transition simulation models (STMs) to simulate changes in forest composition and structure for the revisions of five forest plans in Oregon and Washington. We illustrate the use of STMs to examine current and desired forest conditions, develop forest plan environmental impact statement (EIS) alternatives, and evaluate environmental effects, with examples from the Okanogan-Wenatchee National Forest (Washington, U.S.A.). Model parameters include ecosystem states and natural and human-caused disturbances, which were derived from empirical studies, published literature, and expert opinion. Forest growth rates were calibrated using Forest Vegetation Simulator (FVS) modeling of national forest inventory plot data and FVS post-processors, such as the Preside program. Preside was used to classify forest inventory plots into STM states, estimate mean residence times (within a state) and transition probabilities (between states), and summarize the alternative pathways between states. In some cases for the Okanogan-Wenatchee National Forest, Preside showed longer residence times for dense multi-story stands than assumed in previously developed STMs for the forest plan area. STMs are being used to simulate the effects of alternative combinations of forest treatments such as forest thinning, regeneration harvest, and prescribed burning. The effects of treatments on a suite of indicators and decision criteria, including forest structural states, departure from reference conditions, woody biomass yield, wildlife habitat, and fire severity and frequency, will be estimated using the output of STMs. STMs used in forest plan revisions have proved useful in testing assumptions, developing alternative restoration scenarios, and documenting current knowledge.

Parent Publication

• Proceedings of the First Landscape State-and-Transition Simulation Modeling Conference, June 14–16, 2011, Portland, Oregon

Citation

Shlisky, Ayn J.; Vandendriesche, Don. 2012. Use of state-and-transition simulation modeling in National Forest planning in the Pacific Northwest, U.S.A. In: Kerns, Becky K.; Shlisky, Ayn J.; Daniel, Colin J., tech. eds. Proceedings of the First Landscape State-and-Transition Simulation Modeling Conference, June 14–16, 2011, Portland, Oregon. Gen. Tech. Rep. PNW-GTR-869. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 23-42.