Insects are devouring Colorado's trees, thanks to climate change: Report

The Hill

08-04-2025

Climate-induced warming is fueling the proliferation of insects keen on invading Colorado's forests and leaving the trees they devour for dead, a new report has found.
After a wet and cool 2023, weather in the Centennial State shifted back to near-record heat and minimal precipitation last year — driving the spread of forest pests and weakening the defenses of trees, according to the report, released by the Colorado State Forest Service.
'Trees in Colorado can't catch a break as our climate becomes warmer and dryer,' Matt McCombs, state forester, said in a statement.
'This ongoing trend toward persistent drought and higher temperatures not only makes trees easier prey for insects but increases the risk of large and severe wildfires,' added McCombs, who directs the Forest Service, housed at Colorado State University.
The 2024 Report on the Health of Colorado's Forests showed that bark beetles and other invasive insects expanded their forest footprint in a hot and dry 2024.
The type of tree most affected was the Western spruce budworm, which incurred 217,000 acres of injury in 2024, as opposed to 202,000 acres in 2023, per the report.
Another insect flagged in the report was the mountain pine beetle, which has been building populations along Colorado's Front Rage and in other parts of the state. In total, mountain pine beetles have damaged about 5,600 acres of forest.
An additional culprit was the Douglas-fir beetle, which exceeded levels not seen in almost a decade, although the balsam bark beetle was 'the deadliest forest pest in Colorado for the third year in a row.'
As the death toll of trees increase, so, too, does the likelihood of wildfires, the authors warned. Dense, homogenous forests can be slow to recover from disturbances, leaving material behind that has greater ignition risk, according to the report.
'Couple that with more people living in areas prone to burn, and the state faces enormous challenges,' McCombs said.
The authors therefore recommended that wildfire risk mitigation remain a top priority in Colorado, by taking proactive steps to maintain forest health and establishing fuel breaks when appropriate.
They praised the state for heading in the right direction in these activities, by establishing programs that fund workforce development, landscape resilience and wildfire mitigation, while also providing community-level grants to high-risk areas.
'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,' McCombs added.