Bark Beetles

G.K. Gerber

Forest officials in southern Arizona are trying to keep bark beetles from destroying endangered squirrel habitat.

USDA Forest Service

For many residents of the mountain west, warmer temperatures may not sound too bad.

But small differences in temperature can make a big difference.

Consider bark beetles. They’re native to the region’s conifer forests. Normally, the insects emerge in summer. Females bore into the cambium layer of trees and sever vessels that contain resin, releasing a sticky flow that “pitches out” the beetles. But in weaker trees that lack sufficient resin swarms of beetles can quickly chew enough wood tunnels to kill their hosts.