Fire and Insect Interactions in North American Forests

Document Type


Journal/Book Title/Conference

Fire Science and Management

Publication Date

Summer 8-9-2022




Purpose of Review

Fire and insects are major disturbances in North American forests. We reviewed literature on the effects of fire on bark beetles, defoliators, and pollinators, as well as on the effects of bark beetle and defoliator epidemics on fuels and wildfires.

Recent Findings

Fire has direct and indirect effects on insects, but our understanding of these effects is confounded by several factors identified in this review. Direct effects are expressed through insect mortality due to exposure to fire, with few studies published on this topic. Indirect effects are expressed through changes in insect hosts and forest conditions, with bark beetle responses to fire-injured trees following prescribed fires and low-severity wildfires being the most studied. Although fire effects on pollinators are an emerging field of research, it is clear that fire can benefit pollinators by creating more open forest conditions, which, in turn, enhance floral resource availability. Bark beetle and defoliator epidemics can exert large effects on fuels, but their effects on wildfires are mixed. Differences in the severity, extent, and timing of epidemics, fire regimes, fire weather, topography, and the metrics and models used to assess wildfires, among other factors, confound our understanding of the effects of bark beetle and defoliator epidemics on wildfires.


Fire has both positive and negative effects on insects. Bark beetle and defoliator epidemics have positive and negative effects on wildfires. Additional study of these relationships is warranted given the effects of climate change on forests and forest disturbances, recent declines in some pollinator species in North America, and interests in restoring fire-adapted forest ecosystems.