Abstract
Fire is an important form of natural disturbance in nearly all terrestrial ecosystems in the western United States, and it serves as a critical link between climate change and ecosystem response (Agee, 1990; Swetnam and Betancourt, 1998). The nature of these linkages depends on the time scale of interest. On short time scales, climate/weather and vegetation characteristics affect the fire conditions of particular years (and decades), as well as the dynamics of post-fire ecological succession. On centennial and millennial time scales, large-scale changes in climate alter regional fire regimes and vegetation composition. The linkages are especially complex in the western U.S., where fire regimes vary across environmental gradients and include frequent surface fires as well as infrequent stand-replacement events.