Forests that succumb to wildfires across the Southern Rocky Mountains may be unlikely to return, and instead live on as grasslands or shrub lands, concludes a new research paper from Colorado academics.

“We project that post-fire recovery will be less likely in the future, with large percentages of the Southern Rocky Mountains becoming unsuitable for two important tree species — ponderosa pine and Douglas fir,” said lead author Kyle Rodman, who was with the University of Colorado’s geography department at the time of the study.

Authors from UC, the U.S. Forest Service, Northern Arizona University, Colorado State University and the University of North Carolina Wilmington examined 22 areas of fire burn encompassing 710 square miles. The territory spanned southern Wyoming to Northern New Mexico, some of which burned as early as 1988.

The researchers modeled the forests prior to the wildfires, then examined young trees to measure forest resiliency. They found forests at high elevations with lower temperatures and more precipitation were more successful in recovering.

“This study and others clearly show that the resilience of our forests to fire has declined significantly under warmer, drier conditions,” said Tom Veblen, a geography professor at CU Boulder.

Forests that were the victims of more recent fires proved less resilient, as did forests along the Front Range. Researchers noted that high greenhouse gas emissions in the future could result in single-digit percentages of Douglas fir and ponderosa pine forest ever recovering.

The study was published on Aug. 17 in the journal Global Ecology and Biogeography.