DENVER (KDVR) — Emerald ash borer — it's a name that has begun to pop up all over Colorado.

A recent study by Colorado State University, Fort Collins, indicates why the name has spread and also explains why it's not a name you should look forward to hearing about.

The emerald ash borer spread significantly throughout the summer in 2025, according to a press release from the Colorado State Forest Service. The invasive species has now been detected in more than 20 cities in the Front Range, including Denver for the first time this year.

Emerald ash borers are non-native beetles that attack and kill stressed or healthy ash trees, with the trees typically dying two to four years after being infested.

CSU said that ash trees make up about 15% of the urban trees in Colorado, so the invasive

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