Climate affects the geographic distribution of species. In the Pacific Northwest Region, the snowpack has been significantly reduced and the summer drought period extended since the 1970s. As a result, forests have become more susceptible to outbreaks of insects, diseases, and fire. These disturbances are particularly acute on lands set aside as parks, wilderness areas, and conservation reserves. We propose to evaluate with a process-based tree growth model how changes from historical, current, and predicted future climatic conditions might affect the ability of a select group of species to produce defenses against attack by native pests. This feasibility study has three components. We will first test the model?s ability to predict current geographical distribution patterns, based on observations recorded on U.S. Forest Service Forest Inventory and Analysis survey plots. Next, we will evaluate the model?s ability to delineate areas where species h ave become more susceptible to insect and disease attack since the 1970s, using Landsat and MODIS imagery to confirm outbreaks. Finally, we will incorporate climatic projections from Goddard Institute for Space Studies GCM at decadal intervals to map expected changes in species ranges through the end of the century. We will co-sponsor a series of workshops with the U.S. Forest Service, National Park Service, and The Nature Conservancy to demonstrate the modeling approach, and to transfer the modeling software with documentation to these end users.