In this episode of Behind the Scenes at Rocky Mountain National Park, Michael Edwards talks about the Mountain Pine Beetle problem.
(From the National Park Service) Bark beetles are native insects that have shaped the forests of North America for thousands of years. Bark beetles range from Canada to Mexico and can be found at elevations from sea level to 11,000 feet. The effects of bark beetles are especially evident in recent years on Colorado's western slope, including Rocky Mountain National Park (RMNP) with a severe epidemic of mountain pine beetle occurring in Grand County.
Hard winters with cold temperatures can kill beetle eggs and larvae wintering under a tree's outer bark. Related to general climate warming, average winter temperatures in the Rocky Mountains have been higher than normal over the past ten years. Trees have also been weakened by a prolonged period of low precipitation. The combination of milder temperatures and low precipitation has aided a vast outbreak of beetles.