The intensity of the infestation of the most damaging forest pest in Colorado is starting to decline in Grand County, according to a new aerial survey from the US Forest Service.

Results of a 2020 aerial survey on forest pests like the spruce beetle, a native species that attacks Engelmann spruce trees, showed the infestation in Grand County is declining, even as it grows in other counties, such as La Plata and San Juan.

The USFS attributes some of the decline to a lack of large-diameter spruce trees, which were killed off in earlier years by the beetles. However, beetles remain active in Rocky Mountain National Park.

Spruce beetle infestations are intense in other parts of the state, including newly infested areas in Gunnison and Chafee counties.

The drought conditions and warmer temperatures of last year can exacerbate infestations by weakening trees.

“Unfortunately, our dry conditions are optimal for insect epidemics and tree diseases in many parts of the Rocky Mountains,” said Tammy Angel, Acting Regional Forester for the USDA Forest Service, Rocky Mountain Region. “Where possible, managing forests for age and species diversity can increase resiliency while ensuring diverse wildlife habitat, cleaner air and water, timber and grazing resources, and greener, safer landscapes for recreation.”

The spruce beetle has been the most damaging forest pest in Colorado for the past nine years.

Over 16 million acres of Colorado forest were surveyed, however, the USFS was unable to do a complete aerial survey due to COVID-19, which makes the data incomparable to previous years.

For more results from the 2020 aerial survey, please visit bit.ly/COForestHealth2020.