Unlike the predictable vegetation and ecosystem changes typical after wildfire or timber harvesting, the outcomes of insect outbreaks remain poorly understood. Historic forest management alters stand structure, species composition and tree susceptibility during beetle outbreaks. For example, forest mortality and stream N export are lower in multiple-age stands compared to old-growth watersheds with proportionally more, large lodgepole pine trees. Tree regeneration and nutrient cycling following combined bark beetle and wildfire disturbances are also modified by historic harvesting. These current studies underscore the legacy of forest management and how it contributes to post-disturbance responses.