Bark Beetles Continue To Devastate Colorado Forests. Climate Change Isn’t Helping

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Photo: Spruce Beetle San Juan Forest Damage
Spruce Beetle damage in the San Juan National Forest in 2018.

Bark beetle outbreaks have continued to grow in parts of Colorado, and climate change could make the situation worse.

The State Forest Service does a yearly flyover to track and map the damage. Dan West is an entomologist with the state, and said one notable finding from the 2018 survey is the continued spread of the spruce beetle.

West talked to Colorado Matters about what’s being done about the beetle, and how the damage will impact the ecosystem for years to come.

The bug is different from the mountain pine beetle, known for its damage to lodgepole pine. West said the spruce beetle has been the most widespread and destructive forest pest in Colorado for seven consecutive years.

“About 40 percent of our spruce fir forests have been affected by spruce beetle since the year 2000," West said.

The most damaged areas are in and around Rocky Mountain National Park, and parts of the San Juan Mountains, West Elk Mountains and the Sawatch Range. West said record-warm temperatures and record-low precipitation help the beetle thrive.

“That means there’s much fewer water resources that are available to these trees, which they use as a defense mechanism against attacking bark beetles,” West said. “So if it’s warmer and dryer in the near future, those prolonged drought events and warm periods cause these bark beetles to emerge earlier, have longer periods to be able to attack trees, and have fewer defenses that they’re fighting.”