Extreme heat, dry summers are the main cause of tree death in Colorado’s subalpine forests.

Even without the bark beetle and wildfires, new research has shown that trees in Colorado’s subalpine forests continue to die, and this trend is accelerating. In fact, tree deaths in Colorado’s subalpine forests have more than tripled over the past decade since the 1980s.

We have bark beetle outbreaks and wildfires that are apparently causing tree death in Colorado. But we see that the death rate is seriously increasing only due to heat and drought. This is an early sign of climate change.

Robert Andrus, lead author of the study at the University of Washington
It is well known that rising temperatures and droughts are killing forests around the world. But here in Colorado, the researchers found that heat alone caused 70% of tree deaths in 13 subalpine forest areas they have measured over the past 37 years. In comparison, 23% of tree deaths are due to bark beetles and about 5% due to wind damage.

The mortality rate is alarming, Andrus added.

With temperatures in Colorado rising rapidly since the 1980s and likely to rise by 2.5 ° C or more in the next few decades due to climate change, the rate of tree death will only increase.