A firefighter shovels smoldering debris onto a controlled fire in Laramie, Wyo. Prescribed burns can drop wildfire emissions by as much as 60 percent in certain forests, research finds.
AP Photo/Laramie Boomerang, Ben Woloszyn
THE GIST:
- Satellite data show that prescribed burns release less carbon than wildfires.
- Prescribed burns burn with less intensity and leave more carbon in unburned plants.
- Eventually it should cost less to control fires by treating land with fire than by fighting fires.
Widespread prescribed or "controlled" burns in the wilds of the western United States can lower wildfire emissions of carbon dioxide by 18 to 25 percent, and by as much as 60 percent in certain forests, according to a new study.
By combining satellite observations and computer models of emissions, researchers have shown how prescribed burns -- aimed at reducing the amount of low-laying combustible material on the land -- burn a lot less material than the big wildfires that burn everything to the ground.
At the same time, prescribed burns drop the danger of future fires and allow more carbon to stay locked up in plants and on the ground.
The researchers came this conclusion after first gathering satellite data on wildfires from 2002 to 2008 in the Western United States, calculating the "fuel load" (burnable plant material) on the ground, and then the emissions from the fires, explained researcher Christine Wiedinmyer of the National Center for Atmospheric Research.
"Then we asked what would happen if those (wildfires) were all prescribed burns," Wiedinmyer told Discovery News.
Wiedinmyer is the co-author of a paper about the work in the latest issue of the journal Environmental Science and Technology. The answer was it would release significantly less of the greenhouse gases that are responsible for the well documented rapid rise in temperatures worldwide.
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"This line of work they're pursuing is really important," said Anthony Westerling of the Sierra Nevada Research Institute at the University of California at Merced. Westerling studies the connection between climate change and wildfires. Climate change could add more urgency to the the need to reduce the fuel load with prescribed burns, since a drier climate could lead to more wildfires in many areas.
Of course, it's not even remotely possible at present to replace all wildfires with prescribed burns.
"It costs money to put fire on the ground," said forester Matthew Hurteau of Northern Arizona University, a co-author of the study. It takes personnel, the proper weather conditions and permission from local air resources boards, just to name a few of the baseline requirements.
On the other hand, the U.S. Forest Service's 10-year average for fire suppression -- which means putting out wildfires after they have started -- is $1.2 billion, said Hurteau. The cost of suppressing fires versus managing the fuel loads with prescribed burning treatments has even been studied by the General Accounting Office in 1996.
"It penciled out that treating was less costly," said Hurteau. Carbon emissions may become part of that financial equation as well, depending whether the U.S. institutes carbon credit trading or a carbon tax.
But back in the real forests of the West, the reality is that decades of fire suppression had lead to far too much fuel built up on the ground -- a recipe for giant fires. So it's not possible to just switch from fire suppression to prescribed burning overnight, Hurteau said.
"There's going to have to be a period of time when were going to have to do both," said Hurteau.
Tags: Carbon Emissions, Climate Change, Forests, How Stuff Works, The General
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