Douglas-fir Beetle Mitigation

During the Summer of 2021 the City of Aspen, Pitkin County, Aspen Fire, Aspen Skiing Company, Colorado State Forest Service,  ACES, and USFS formed a group to address the spread of bark beetles on the face of Aspen Mountain. Experts from the Colorado State Forest Service who are tracking the beetles estimate that local bark beetle populations are likely to increase due to multiple years of drought in our area. In May 2022, the group placed MCH packets on trees on the face of Aspen Mountain to prevent the spread of Douglas-fir beetles and loss of Douglas-fir trees. This ongoing project is important as it protects our forest health during drought years, and reduces risk from wildfires near homes and the city core. 

In June of 2023 the group will hang new monitoring traps and new pheromone packets in areas of the mountain which were determined to be safe for access during the 2022 project. The map below shows the areas to be treated in 2023. The group plans to continue monitoring and hanging packets in subsequent years until the beetle population subsides.

For More Information please contact David Coon, City Forester.

2023_beetle map


What are bark beetles and why should we be concerned about them?   Douglas-fir bark beetles are small naturally present pests that can kill trees if under stress from drought conditions and their local populations grow to a large number.  If you have Douglas-fir trees especially those that have been subjected to recent drought conditions, you should consider protecting your tree(s).

Is there anything I should do to help protect trees in Aspen?  Make sure your tree(s) get adequate water from Spring through Fall. In addition you can use the MCH pheromone packets detailed below.   

Can I install pheromone packets on my own trees?  Yes, you can order MCH and install it yourself or you can hire a forester or arborist to do it for you.  If you need assistance or direction as to where to obtain MCH packets, you can contact the City Forester at 

How long will trees need to be treated for? MCH pheromone packets will need to be replaced every year until beetle populations have subsided in your area.  We will continue to monitor populations on Aspen Mountain and provide updates.  


Douglas-fir Beetle CSFS 

Wildfire Risk Map - AFPD

Insect & Disease map for Colorado - CSFS


Douglas-fir Bark Beetle Quick Guide

Douglas-fir Flyer