Friday, July 08, 2016

Wildfire, insects, global warming, mismanagement are destroying Western forests

Last year more than 10 million acres of the nation's 766 million acres of forest were destroyed in wildfires, the largest loss since records began being kept in 1960, reports The Economist. More than 30,000 people fought last year's fires, which cost the federal government $2 billion. While this year's fire season had been expected to be less severe, it is now on pace to equal last year's losses. As of July 1, 2.1 million acres have been burned by 26,000 fires, 19 of which were still burning at the time of the report. (Economist graphic)

"The devastation wreaked in American forests by insects is less headline-grabbing, but ecologically as dramatic," the British-based magazine reports. "Last month the United States Forest Service said that, since October, it had recorded 26 million trees killed by the mutually-reinforcing effects of bugs and drought in the southern part of California’s Sierra Nevada range alone. That suggested 66 million trees had died there since 2010."

"Such destruction, caused partly by warming, will itself cause more warming," reports The Economist. "Many American forests are growing denser, in part owing to a reduction in logging, which makes them a significant carbon sink. They suck in greenhouse gases equivalent to around 13 percent of what America emits by burning fossil fuels. Yet USFS predicts that within a couple of decades, because of slowing growth and climate-related blights, the forests will become an emissions source. That would have a commensurate impact on the climate; it would also be grim for America, whose long disdain for one of its greatest bounties, the forests on which its economy was built, is belatedly yielding to smarter, more collaborative sorts of forest management."

"Climate change is estimated to have made California’s drought 15 to 20 percent more severe; in Alaska, where the average winter temperature has risen by over 3°C in the past six decades—over twice the average for the rest of America—its impact is greater," The Economist reports. "By accelerating the melting of winter snow, for example, in Alaska and the mountains of the West—the Rockies, Cascades, Sierra Nevada—hotter temperatures have made the fire season longer. Since 1970 the average duration has increased from 50 to around 125 days; in Alaska, which had its second-biggest year for fires on record in 2015, some of last year’s blazes are still alight." (Economist graphic)

"Mismanagement is also fueling the flames," reports The Economist. "Ever since 3 million acres of Idaho, Montana and Washington went up in smoke in 1910, the government has suppressed fire zealously. It was said that any new blaze must be extinguished by 10 a.m. the next day. This has stopped some sequoias from reproducing for decades. It also removed the self-moderating effect of frequent fire from a landscape prone to burn. Logging, followed by dense modern tree-planting, reinforced the effect. Where most western woods were once dominated by well-spaced large trees, they are now a tangle of smaller specimens, fighting over too little water, atop rising mounds of brush." (Read more)

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