Tree rings may hold secret to where wildfires spark in the Southwest

Nov 22, 2021

Increasing drought and tree mortality rates are causing forests in the American Southwest to die earlier and quicker –– which can add fuel to devastating wildfires.

But, new research shows that scientists might be able to predict where future wildfires burn by taking a look at a tree’s growth rings. 

Tree rings are usually used to tell a tree’s age –– that’s because as a tree grows, layers of light and dark wood are added to the trunk’s girth. 

But below the surface, taking a look at the cellular level in these rings can also tell scientists how drought-stressed a tree is. 

And researcher Steven Voelker of Michigan Tech University said this is the key to predicting early warning signs for dying forests in specific areas.

“This is important globally because the more carbon we can store in our forests over the long term––that can provide offsets to the amount of emissions our society is releasing,” Voelker said.  

On a local level, it could also save beloved forests from burning down.

Voelker and other researchers found that as stands of trees became thicker due to suppression of fires, trees resorted to using more of the heavier stable isotope of carbon for photosynthesis. And that signaled that they are drought-stressed and more susceptible to wildfires.  

It’s expensive and time-consuming, but Voelker argued this technique can be used to more accurately decide where to prescribe burns or thin forests in a warming climate in New Mexico and the Southwest.