Forest fire management isn't a game of whack-a-mole -- you can't just suppress fires all the time and prevent them from ever occuring. For some forests, allowing the occasional fire might actually encourage stable forest growth and carbon storage.

That's according to a new study by Matthew Hurteau of Northern Arizona University and Matthew Brooks of the USGS Western Ecological Research Center, who reviewed wildfire research from recent decades. 

Hurteau and Brooks say that historical fire suppression practices have apparently led to less frequent forest fires. But in dry temperate forests like the ponderosa pines of Arizona and mixed-conifer forests of California, the long-term impact is a negative one.

Less fires means that young trees and fallen limbs -- ripe fuels for potential fires -- have accumulated in some forests, since normally they would burn off on a regular basis. These larger fuel stocks have made today's forest fires more severe and kill more trees.

The result is that trees in dry temperate forests are getting killed by fires faster than they can grow back. "And since burning trees release carbon and growing trees store carbon, the result is that some of our forests are becoming a net source of carbon emissions," says Hurteau.

To reverse this trend, Hurteau and Brooks say forests need to be managed according to their natural fire regime. Wet, coastal forests of the Pacific Northwest might do alright with rare, severe fires, but dry temperate forests require more frequent, but less severe fires.

Brooks, who is based at the WERC Yosemite Field Station, says that one way forest managers can help return dry temperate forests to their original fire regime is to allow low- to moderate-severity wildfires to spread when they happen.

"A dry temperate forest returned to its fire regime of regular burns is a forest that stores more carbon, provides more habitat and timber, and isn’t prone to wide-spreading, tree-killing fires."

Read more study recommendations in the USGS press release and the NAU press release. Download the original BioScience paper here: http://dx.doi.org/10.1525/bio.2011.61.2.9

-- Ben Young Landis

Top: In managing forests for timber resources and carbon storage, you might have to let the occasional fire pop up. Image courtesy of Kenneth B. Moore under Creative Commons License.