An outbreak of spruce beetles exploded across the forests of
Southwest Colorado last year, according to the results of an
aerial survey released Wednesday. The outbreak will erase some
of the region’s high-altitude stands of trees for many decades.
“The forest is ripe for the beetle to move through,” said Bob
Cain, a U.S. Forest Service entomologist. The drought, dense
stands of mature trees and warm winters all make for ideal
conditions for the beetles, which bore into trees to feed and
lay eggs. The size of the active outbreak more than doubled in a
year. The annual study found spruce beetles active on 311,000
acres, including 183,000 acres that weren’t detected in the 2011
survey. The outbreak has covered more than 1,400 square miles
since it began in 1996. “Even our acre numbers we get from the
aerial survey don’t really capture it,” Cain said. Infected
trees often take a couple years to die, so the infestation will
look even more widespread by next year, Cain said. Beetles grow
to adulthood inside trees