DENVER (KDVR) — A tree-killing bug that has been in Colorado for a decade is now affecting areas where significant infestations were not seen previously. 

“For the 10th year running, spruce beetle again becomes our most deadly pest across Colorado,” Colorado Forest Service entomologist Dan West said. 

He is part of a team made up of Colorado Forest Service and U.S. Forest Service experts that uses small airplanes to monitor diseases and infestations that affect Colorado’s forests. 

According to their latest findings, spruce beetles affected 53,000 acres in Colorado in 2021. While the total acreage is slightly down from previous years, outbreaks are reaching new areas. 

“We’re really starting to see those areas in and around Buena Vista and Salida really become impacted with spruce beetle,” West said. 

Chaffee County alone saw the bugs across 12,000 of its acres.

“It’s happening where we live and it’s happening in the back forties where nobody is frequenting,” West said. 

According to West, increased bark beetle activity is a direct result of prolonged drought, “the way trees defend themselves is, in short, with water,” he said.

Drier conditions mean the trees can not fight off the pests, allowing them to easily take over and spread. 

“Unless we have data points like this and unless we kind of know well where is the disturbance and where are we likely to see it move, we’re kind of shooting in the dark,” West said. 

In addition to helping land managers pinpoint where to focus resources in fighting bark beetles, the annual aerial survey also helps predict where there could be increased fire danger in areas with beetle kill. 

“It’s not creating more fuel, right? The trees aren’t growing more after they’re dead. What’s happening is their needles are raining down onto the forest floor or small limbs are coming down onto the forest floor so should a wildfire occur in those areas where there’s been bark beetle the fire behavior is more intense,” West said.