Beetle-Kill Correlated with Fires? Gaps in the Research

“Forest Service researchers,” reports the May 31 Summit County [Colorado] Voice newspaper, “continue to study the dynamics of beetle-killed forests and wildfires” and have published a study warning against generalized assumptions. “These findings suggest that it is not possible to reliably generalize about the effects of bark beetle-caused tree mortality on fuels or fire characteristics,” said the Forest Service’s Jane Hayes, assistant director of the Pacific Southwest Research Station, and one of the co-authors of the study, which refers to plentiful “gaps in the research.”

The study affirms that beetle outbreaks can be a factor, but that other factors may be just as significant: time elapsed since the outbreak, type of fuels, and “fire characteristics”; climate change (or “microclimate change”) may be involved and possibly changes in wind patterns and snowpack accumulation associated with climate change and “subsequent influences on fuel moisture during spring and summer.” All of which “have yet to be quantified.” What to do? More research.

From the Report: “Resource managers urgently need information about this interaction. Beetle outbreaks and wildfire are both influenced by climate, and warming projections imply increasing forest disturbances in the coming decades. Greater understanding of the effect of beetle-killed trees will provide better information to resource managers who need to consider how such trees affect future wildfire characteristics. Payoffs of investments of time, money, and effort to treat stands to reduce fire hazard will be maximized with such knowledge.”

Got it? Beetles are a factor, yes, but it’s complicated. We wonder whether the study identifies withdrawal of management as a quantifiable factor in fire ignition and propagation and whether studying this relationship might also have payoffs. Those affected by this year’s record forest fire season will want to know.