From the late 1990s through 2013, the Mountain Pine Beetle (MPB) affected 3.4 million acres of forests in Colorado, killing 90% of trees, in Summit, Grand, Eagle and Routt counties.
Since about 2021, the Front Range began to see increased signs of beetle kill and according to Alicia Doran, Jeffco’s Invasive Species Management Program Manager, as of November 2025, there were over 575 unique sites that are affected.
Minimizing the spread of the MBP is a key concern of residents. Wildfire risk is also a key concern as Jeffco ranks #1 in Colorado for the number of homes in high and extreme wildfire risk areas with Evergreen and Conifer being among the highest risk (www.jeffco.us). Homeowners and Jeffco officials have spent considerable time, resources and energy to address both of these concerns.
In this section, we explain that there is a direct relation between forest health, the MPB and wildfire risk.
Conifer Area Council featured 3 speakers from Jeffco at their November 2025 Town Hall meeting to inform residents about the MBP, what they are doing and what residents can do to mitigate beetle kill. More than 200 people showed up to hear from these experts what they know, what is being done and what residents can do to help mitigate MPB kill.
To see and hear the experts first-hand that presented at our Town Hall meeting, click this link. You can also find it on our website’s main page under Town Hall meetings. We have links to all previous Town Hall meetings here as well.
Alicia Doran, Program Manager, Jeffco Invasive Species Management (THE expert on the MPB) provides these additional links.
CSFS Forest Pest Page https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/
CSFS Golden Office https://csfs.colostate.edu/golden/
Jeffco Invasive Species https://www.jeffco.us/jcism
10 Key Points to Know About Mitigation of MPBs
There are steps you can take to protect your trees and help prevent the spread of beetle kill.
#1 – Mitigation includes on-site solar, chipping, mastication, peeling and burying. For single, high value trees, insecticides may be used. Pheromones may be used to repel MPBs but their effectiveness varies considerably.
#2 – Early detection is key. Start in October and focus on green trees. Signs that MPB have entered your tree include popcorn-shaped pitch tubes or resin, sawdust-like piles at the base of the trees called frass, or small holes left by woodpeckers.
#3 – Healthy forests are more resistant to pests and wildfire. Healthy: Sparse tree clusters. Dense tree spacing causes competition for resources, leaving trees vulnerable to attacks. MPBs seek distressed trees … they can smell ‘em. Thin your trees!
#4 – Mitigate early! Many homeowners choose to mitigate on-site by felling trees, cutting them into 2-4 feet lengths and using the sun or sun with plastic covering to essentially “cook” the beetles inside. For sunlight only – April 15 is the latest date. If using a plastic covering – May 15 is the latest date if you want to catch the beetles before they fly. If chipping or mastication best to complete your work before June 1. It is best to cut green trees down when beetles are not flying Oct 1 – June 15.
#5 – If your trees are brown or red it’s too late, beetles have killed the tree and have flown to affect another.
#6 – Is anyone doing anything about this? Yes – Jeffco has a 5-person team that works to create healthy Open Space parks. Led by Tony Auciello, the natural resources team lead, in 2025 the team was able to thin about 24 acres and spent 800 hours cutting, peeling, and masticating trees to eliminate MPBs and create healthier forests.
#7 – MPBs primarily affect many pine trees, including lodgepole, ponderosa, limber and bristlecone.
#8 – In general, MPBs attack trees from mid July – mid September
#9 – Logs containing live MPBs should not be moved until they are debarked, solar treated, or chipped. Landowners need to inspect their forests and control MPBs if they are found.
#10 – Contact the experts for more information. There are numerous tree-service companies in the local area who can help you.
Pitch Tubes
Pitch Tube Closeup
MPB Frass
