02 August 2009

Pine Beetles, Fire and Climate Change

Based on the comments, I see an interest in a thread on the pine beetle outbreak here in the west. As luck would have it, the current issue of the University of Colorado Arts and Sciences magazine has an interesting article on just this topic by Clint Talbott. Here is a provocative excerpt (emphasis added):

The forest around Grand Lake, Colo., is neither pretty nor, for the most part, green. Whole mountainsides are draped with dead trees bearing orange needles and bare branches. The pine beetles have attacked, and people have responded with chainsaws, insecticides and anxiety about fire.

Conventional wisdom suggests that decades of U.S. Forest Service policy of extinguishing all fires on public lands—also called “fire suppression”—have left forests more prone to beetle attacks, and that these dead trees are more likely than live trees to erupt in wildfires.

But the latest and best scientific research does not buttress conventional wisdom. The research suggests that the pine-beetle outbreaks coincide with warmer, drier years. It finds no compelling evidence that once the dead needles have fallen from the trees (i.e. when the “red phase” disappears a few years after attack) dead stands of pine are more likely than live stands to burn. Scientists also find no evidence that this outbreak is unprecedented over time spans of several centuries, or that human fire-suppression has made western U.S. forests unusually prone to fire.