The extent and severity of bark beetle (Curculionidae: Scolytinae) epidemics and the frequency of large, severe fires have reached unprecedented levels in recent decades, and these trends are expected to continue with ongoing climate change. Insects and fire have tremendous ecological and economic effects in western forests, yet their interactions are poorly understood. We combined field studies and simulation modeling to understand how bark beetle infestation and post-outbreak management affect fire hazard in two widespread but contrasting forest types, lodgepole pine (Pinus contorta) and Douglas-fir (Pseudotsuga menziesii) in the Greater Yellowstone Ecosystem (GYE) in northwestern Wyoming. We directly addressed key barkbeetle research priorities identified by US Forest Service scientists for the western US, via three primary questions and several supplemental studies. (1) How do effects of bark beetle outbreaks on fuel profiles and subsequent fire hazard differ between lodgepole pine and Douglas-fir forests? (2) How was the severity of recent fire in lodgepole pine and Douglas-fir forests affected by prior bark beetle infestation, and does the combination of beetle infestation and fire compromise forest recovery? (3) What post-beetle fuel treatments are likely to change the hazard of subsequent severe fire in lodgepole pine and Douglas-fir forests
