Beetle-Killed Trees Affect Local Weather

In the Rockies, it’s common to see entire mountainsides blazed reddish-brown—the result of thousands (if not millions) of trees killed by the insatiable pine beetle. Spurred on by warmer temperatures, these tree-boring insects have sparked fears of massive forest fires and a drastically altered landscape. Plus, they’re freaking ugly.

But there’s more bad news: New research seems to show that beetle-kill forests can actually influence local weather patterns. The National Center for Atmospheric Research has launched a four-year study to determine exactly how much change will occur because of damaged forests.

“Forests help control the atmosphere, and there’s a big difference between the impacts of a living forest and a dead forest,” says NCAR scientist Alex Guenther, a principal investigator on the project. “With a dead forest, we may get different rainfall patterns, for example.”

When large sections of forests die, precipitation levels can drop — which means increased water tensions in the already-parched Rockies. Living trees also cool an area by both reflecting sunlight and creating an evaporative cooling effect when they pull moisture from the ground and return it to the atmosphere. Acres and acres of dead trees could mean average temperature increases of 2-4 degrees.

Worst of all, dead trees can actually make smog and pollution worse. Dead trees don’t absorb carbon from the air, and stressed forests can actually leach more hydrocarbons into the air, compounding air quality problems in urban areas.

So far, the only effective way to kill pine beetles without damaging the environment is to let nature strike them dead with an extra-hard freeze. Those have been few and far between in recent years, so here’s hoping for a cold winter.

Impact of Beetle Kill on Rocky Mountain Weather, Air Quality (Science Daily)