DENVER - An annual aerial survey of forest health in Colorado shows the mountain pine beetle epidemic is slowing dramatically, but the spruce beetle outbreak is expanding.
The U.S. Forest Service and Colorado State Forest Service said the mountain pine beetle epidemic has spread by 31,000 acres, down from an increase of 140,000 acres reported last year.
Since the first signs of the outbreak in 1996, the infestation has grown to nearly 3.4 million acres, or roughly 5,300 square miles. The infestation remains active from Estes Park to Leadville.
However, the spruce beetle outbreak spread to 183,000 new acres in 2012, bringing total infestation since 1996 to about 924,000 acres.
Beetle activity has increased as trees have been stressed by factors including dense stands of trees, drought and warmer winters.