Thursday, April 30, 2015

California’s Forests Have Become Climate Polluters

The Zaca Fire sparked to life in Santa Barbara County, Calif., in 2007, eventually burning more than 200,000 acres. (​Credit: U.S. Forest Service/Wikipedia) Click to Enlarge.
A Californian task force has been handed the confounding task of figuring out how forestry and land management practices could be improved to prevent what scientists say are surprisingly high levels of climate pollution escaping from its forests and other wildlands.

A new study has shown that greenhouse gases are billowing out of the state’s forests faster than they are being sucked back in, with unnaturally intense wildfires mostly to blame.
From 2001 through 2010, the state’s wildlands were responsible for about 8 million tons of carbon pollution annually — more climate pollution than is released every year by the entire economy of Vermont.

That was the conclusion of a sophisticated analysis requested and partly funded by California’s air resources board.  Wildfires affecting a small portion of the state were responsible for two-thirds of the estimated losses of carbon from what had been living plants.

Under more stable natural conditions, the state’s forests would be expected to absorb about as much carbon as they lost every decade.  At a time of unnaturally high carbon dioxide levels, the forests would ideally absorb more of the greenhouse gas than they produce.  But the balancing act has been thrown off kilter.

“There's a long history of discussion of using forests to sequester atmospheric carbon,” said Michael Goulden, a University of California at Irvine associate professor who studies the state’s forests, but who wasn’t involved with Gonzalez’s research.  “This paper points out that any increase in forests’ carbon stock may prove ephemeral.  Eventually, forests are disturbed, and then this extra carbon is released.”
Decades of fire fighting are the major culprit.  Fire suppression policies have allowed fuel to build up on forest floors, and they have allowed allowed forests to grow thick with young trees that burn hotter and over larger areas than was the case under more natural conditions.

Read more at California’s Forests Have Become Climate Polluters

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