FORT COLLINS, Colo. – The annual forest health report, released today by the Colorado State Forest Service, assesses the condition of Colorado’s forests during another warm, dry year for the state. Following a wet and cool year in 2023, the shift back to near-record temperatures and below-average precipitation in Colorado last year stressed trees needing several years of mild conditions to build defenses against attack from forest pests. Bark beetles and other insects are building populations in forests across the state and changing fuel dynamics for wildfire as they leave dead and dying trees in their wake.
“Trees in Colorado can’t catch a break as our climate becomes warmer and dryer in Colorado,” said Matt McCombs, state forester and director of the CSFS. “This ongoing trend toward persistent drought and higher temperatures not only makes trees easier prey for insects, but it increases the risk of large and severe wildfires. Couple that with more people living in areas prone to burn and the state faces enormous challenges. The good news is we know Colorado is on the right path to address these challenges and foster forests and communities that are resilient to wildfire and forest pests.”
2024 key takeaways
The 2024 Report on the Health of Colorado’s Forests details what insects and diseases remain the most prevalent forest health issues and where they are increasing their footprints, as well as the science behind the management actions taken to promote wildfire-resilient forests and healthy watersheds.
- Insects and diseases: Western spruce budworm remains the most widespread forest pest in Colorado, according to aerial survey data from the CSFS and U.S. Forest Service Rocky Mountain Region. Data from the aerial survey also indicate mountain pine beetle continues to build populations along the Front Range, in Gunnison County and in parts of southwest Colorado; acres of trees killed by Douglas-fir beetle surpassed a level not seen in nearly a decade; and western balsam bark beetle remains the deadliest forest pest in Colorado for the third year in a row. This year’s report contains interactive maps and data for the public and land managers to see where insects are impacting forests.
- Wildfire-resilient forests: The CSFS and its partners take a science-based approach to managing forests so they are resilient to wildfire. In this year’s report, the CSFS cites peer-reviewed research that underpins the principles of forest management, because active management is critical to help keep wildfires at a low severity and protect the many benefits that forests provide.
- Healthy watersheds: Colorado’s forested watersheds are vital to the nation’s fresh water supply. With a dry climate, frequent droughts in Colorado and growing demand for water, protecting this water supply is a high priority for the CSFS and its partners. This year’s report details how high-severity wildfire can impact water quality, provides examples of costly wildfires that degraded water infrastructure and describes actions the CSFS and water providers take to promote healthy watersheds.
Regional forest health issues
The 2024 forest health report gives an update on the most prevalent forest pests on a regional level:
- Northeast Colorado: Mountain pine beetle is making a comeback along the Front Range after devastating 80% of pine forests in Colorado from 1996-2014. In addition, emerald ash borer continues its spread across the northern Front Range with Fort Collins, Loveland, Lakewood and Centennial all reporting detections of this deadly, non-native insect.
- Southeast Colorado: Western spruce budworm remains widespread in this part of the state, infesting 26,000 acres of forests in Park County alone last year. Spruce beetle is making a notable impact in forests in Costilla, Custer, Huerfano and Park counties, while mountain pine beetle continues to infest pine trees along the margins of the 2013 Black Forest Fire burn scar in El Paso County.
- Southwest Colorado: Western spruce budworm, Douglas-fir beetle and spruce beetle are prominent issues in many counties across southwest Colorado. The roundheaded pine beetle complex expanded its footprint in the Glade area of the San Juan National Forest northwest of Dolores, as well as the Naturita Canyon and Iron Spring Mesa areas of San Miguel County.
- Northwest Colorado: Across higher elevations in northwest Colorado, subalpine fir trees continue to succumb to western balsam bark beetle acting alongside fungi that cause root decay. Piñon Ips beetle is attacking piñon pine trees in Garfield, Mesa and Pitkin counties, while Douglas-fir beetle has heavily impacted Douglas-fir forests in those same counties along with Eagle County.
Each year, the forest health report provides information to the Colorado General Assembly and residents of Colorado about the health and condition of forests across the state. Information for the report comes from an annual aerial forest health survey by the CSFS and U.S. Forest Service Rocky Mountain Region, as well as field inspections, CSFS contacts with forest landowners and special surveys.