Rocky Mountain high-elevation forests burned more in 2020 than they have in 2,000 years, according to researchers from the University of Montana and the University of Wyoming.

UM professor Philip Higuera said he and his team conducted the study of present and historic burn patterns using data collected during 15 years, reports the Daily Montanan. He said that this research is important because it highlights the effects of climate change on the severity of fire seasons.

He said that high-elevation forests are a good indicator of climate change because due to their burn-free periods, they have been less affected by burn mitigations the way lower-elevation forests have.

“We write that these forests are good sentinels of climate change for kind of two reasons,” Higuera said. “First, because they’re high elevation, they’re cooler and wetter compared to low elevation forests. With fire-free periods of one to two centuries, these forests have typically had a lot of dead fuel, twigs, dead trees and stuff on the forest floor, and you’ll see that today. That’s not a consequence of fire suppression; it’s not unusual relative to the past. A hundred years, or 50 years of fire suppression in these forests that typically burn once every one to two centuries has a lot less of an impact compared to fire suppression in low elevation forests that may have burned once every several years or several decades historically.