Interactions between forest insect activity and wildfire severity in the booth and bear complex fires, Oregon

This study investigates how two major groups of forest pests in North America, defoliating insects and bark beetles, influenced subsequent wildfire severity in the Booth and Bear Complex Fires. A secondary goal is to ascertain whether high-resolution plot-based vegetation data are better predictors of fire severity than lower resolution historical vegetation data. General Additive Models were used with an information-theoretic approach to determine the importance of forest insect outbreaks as predictors of fire severity. The models indicate that pest outbreaks were not significant predictors of fire severity and that high-resolution plot-based vegetation data are not superior to lower resolution historical vegetation data. Elevation and weather conditions were the most important controls of severity, while low-resolution vegetation data, slope and topographic position were of secondary importance. These results suggest defoliating insect outbreaks do not appreciably increase fire severity, though this finding should be verified in the context provided by other fires.