Bark-beetle-attacked trees produced more charcoal than unattacked trees during a forest fire on the Kenai Peninsula, Southern Alaska

Abstract

Alaskan boreal forests frequently suffer from outbreaks of bark beetles and fires, factors that appear to combine to alter charcoal production. Charcoal (black carbon) production in forest ecosystems is an important pathway to clarify for a more complete understanding of the effects of fire on carbon cycling in boreal forests. In this study, we aimed to clarify the effects of prevalent outbreaks of the spruce beetle, Dendroctonus rufipennis (Kirby), on charcoal production during forest fires in boreal forests. Snags with prefire damage by the spruce beetle (infested snags) have significantly more charcoal than those undamaged before fire (noninfested snags). This increased amount of charcoal in spruce beetle-damaged trees was probably the result of dried biomass in the canopies of these trees. The results of this study suggest that with changing environmental conditions, the proliferation of insect damage in the boreal forest can modify the effects of fire on carbon sink via a change in the amount of charcoal production.