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, forest officials said Wednesday.
The mountain pine beetle epidemic has spread by 31,000 acres, down from an increase of 140,000 acres reported last year, the U.S. Forest Service and Colorado State Forest Service said. 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.
Meanwhile, the spruce beetle outbreak spread to 183,000 new acres in 2012, bringing the total infestation since 1996 to about 924,000 acres.
The most significant spruce beetle activity has been in southern Colorado in the San Juan and Rio Grande national forests, forest officials said. Spruce beetles typically attack spruce trees downed by high winds, then move into the surrounding trees as the insects' numbers grow.
Beetle activity has increased as trees have been stressed by factors including dense stands of trees, ongoing drought, and warmer winters that haven't been killing off as many insects.
Interim state forester Joe Duda said active forest management to reduce stands of weakened trees, along with a vibrant forest products industry that can use the wood from forest thinning operations, are needed to help reduce risks of massive wildfires blazing through stressed trees.
Late last year, the Colorado companies Confluence Energy and West Range Reclamation won 10-year stewardship contracts to thin national forests in Wyoming and Colorado. At least some of the wood was expected to go toward heating homes. Companies also have stewardship contracts in the Front Range and Pagosa Springs areas.