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Bark Beetle outbreaks expanding in Colorado

Ryan Lockwood

Every year, the Colorado State Forest Service and U.S. Forest Service, Rocky Mountain Region, work together to aerially monitor forest health conditions on millions of forested acres across the state.  

The 2018 survey indicates that bark beetle outbreaks have continued to expand in parts of Colorado. Notable impacts include

  • Approximately 178,000 acres of high-elevation Engelmann spruce were affected by spruce beetles in 2018. Primary areas impacted include forestlands in and around Rocky Mountain National Park, and portions of the San Juan Mountains, West Elk Mountains and Sawatch Range. 
  • Since the year 2000, spruce beetle outbreaks have caused tree mortality on more than 1.8 million acres in Colorado, and approximately 40 percent of the spruce-fir forests in the state have now been affected. 
  • Roundheaded pine beetle, along with associated native bark beetles, has continued to increasingly affect ponderosa pine forests in southwest Colorado. Over the past several years, populations of this insect have risen exponentially, with 27,000 acres impacted in 2018, compared to 11,000 acres in 2017. Record-warm temperatures and record-low precipitation have provided an environmental window that may continue to favor increasing beetle populations. 

"Colorado’s forests are important to the ecological and economic health of our state," said Mike Lester, state forester and CSFS director. “Our efforts in partnership with the U.S. Forest Service ensure that we understand the condition of our forests, so we can design the best treatments to enhance forest health.” 

Lester says the CSFS is dedicated to providing timely, relevant forestry information to the citizens of Colorado to achieve resilient forests. CSFS publications about spruce beetle, Douglas-fir beetle and many other pests, as well as how private landowners can manage them, are available online at