Bugged Forests Bad for Climate

Northern pines are under siege from bark beetles, with some infested stands rapidly losing at least 50 to 80 percent of mature individuals. Over the next couple of decades, the decomposition of those trees is expected to release large amounts of carbon dioxide, a greenhouse gas, posing a potent risk to climate. A new analysis now identifies additional climate repercussions of the severe beetle outbreaks.

Chief among the problems: Even after a forest has ostensibly recovered from a beetle outbreak, it continues to suffer a long-term drop in the rate at which growing trees remove carbon dioxide from the air. That makes the forest less efficient at locking up the carbon dioxide emitted by fossil fuel burning, according to a new analysis by Eric Pfeifer, Jeffrey Hicke and Arjan Meddens at the University of Idaho in Moscow.

A forest may regain its previous biomass in seven to 25 years, but the rate at which it takes up carbon dioxide will remain diminished for much longer—in some cases well over a century, the researchers report in the January Global Change Biology.