Fire and bark beetle interactions

Abstract

Wildland fire and bark beetle outbreaks are both large disturbances in North American forests with the potential to interact over spatial and temporal scales (Hicke et al. 2016; Raffa et al. 2008). The order of the disturbances, fire before bark beetles or fire after bark beetles, influences the outcome of the interaction. Fire and bark beetles are similar in that both can cause massive amounts of tree mortality, alter nutrient cycling, and alter forest structure and species composition, but these disturbances, in isolation and together, also have distinct effects on ecosystems. Several reviews of fire-bark beetle interactions exist with more detailed information (Hicke et al. 2012; Jenkins et al. 2008, 2012, 2014; Kane et al. 2017). A basic background of bark beetle biology is necessary to understand fire-bark beetle interactions. Numerous bark beetles (Coleoptera: Curculionidae, Scolytinae) species are native insects to North America that are capable of irrupting in population to kill mature trees (Wood 1982). Host tree species is specific to the bark beetle species. Bark beetles require living phloem to successfully reproduce; therefore, they only attack live trees. Life cycle varies by geographic region and bark beetle species, but generally, beetles communicate via pheromones to mass attack a live tree by boring through the bark on the tree’s main stem. The coordinated mass attack overwhelms a tree’s defenses to allow mating and reproducing (Raffa and Berryman 1983). Females construct galleries in the phloem and deposit eggs. As eggs develop into larvae and then pupae, they feed on phloem. When mature, the new generation of beetles bore out of the tree through the bark to attack other trees.

Citation

Hood, Sharon M. 2020. Fire and bark beetle interactions. In: Manzello, Samuel L., ed. Encyclopedia of Wildfires and Wildland-Urban Interface (WUI) Fires. Cham, Switzerland: Springer. 6 p.