DENVER -- The bark beetle outbreak is expanding in Colorado and foresters are concerned.
Every year, the U.S. Forest Service aerially monitors the health and condition of millions of acres across Colorado.
The 2018 survey shows the bark beetle outbreak is spreading.
Since 2000, spruce beetle outbreaks have killed trees on more than 1.8 million acres in the state and approximately 40 percent of the spruce and fir forest have been affected.
Approximately 178,000 acres of high-elevation Engelmann spruce trees were affected by beetles last year.
The primary areas for the threat are around Rocky Mountain National Park and portions of the San Juan Mountains, West Elk Mountans and the Sawatch Range.
Record-warm temperatures and record-low precipitation have provided an environmental window that could continue to favor increasing beetle populations.