Developing a production possibility set of wildlife species persistence and timber harvest value

An integrated model, combining spatial wildlife population and timber harvest and growth models, was developed to explore tradeoffs between the likelihood of persistence of a wildlife species, the northern flying squirrel (Glaucomys sabrinus), and timber production on a landscape on the west side of the Oregon Cascade Range. A simplified wildlife model was developed from the fully parameterized spatial wildlife model, using a habitat neighborhood-weighting scheme, for use in the optimization. Simulated annealing, a heuristic optimization technique, was used to solve for harvest schedules that maximized the net present value of timber harvest subject to a target value for likelihood of species persistence over a 100-year planning period. By solving this problem for a range of species persistence targets, a production possibility frontier was developed that showed tradeoffs between timber harvest value and likelihood of species persistence on this landscape. Although the results are specific to the wildlife species and the landscape analyzed, the approach is general and provides a structure for future models that will help land managers and forest planners to understand tradeoffs among competing resource uses.