Bark beetle infestation grows in Colorado, Wyoming

Tree-killing bark beetles decimated 550,000 acres of forests in Colorado and Wyoming last year, bringing the total area ravaged by the insects in both states to 4 million acres since 1996, the U.S. Forest Service said on Sunday.

"The significance is that the trajectory is moving north and east into more visible and populated areas," Janelle Smith, spokeswoman for the U.S. Forest Service, told Reuters.

Federal and state foresters just released their annual aerial survey of impacted lands across the two Rocky Mountain states. The main culprit is the mountain pine beetle responsible for infesting 400,000 acres in Colorado and southern Wyoming.