Sunday, August 3, 2008

How US national parks manage fire risk

Christian Science Monitor explores controlled burns in US national forests: Officials at the Sequoia & Kings Canyon National Park in California adopted an unusual wildfire policy four decades ago: When possible, they'd let fire be fire. If a blaze didn't threaten homes or people, park officials would let it burn. The idea was to let natural processes take over and prevent wildland from becoming too overgrown and vulnerable to a conflagration.

Forty years on, this strategy – known as "fire management" – is in place in wilderness areas across the West despite constant revision after a catastrophic miscalculation in the late 1980s at Yellowstone National Park in Wyoming. But as this year's extraordinary wildfire season in northern California shows, the strategy isn't always practical.

Firefighters at Yosemite National Park, for instance, normally let fires burn thousands of acres each year, sometimes for weeks. This year, the epidemic of nearby wildfires has caused so much pollution that Yosemite allowed only four fires to burn because of smoke regulations.

Yosemite allows fires to burn in 80 percent of the park, van Wagtendonk says. In some cases, firefighters burn off overgrown brush in the backcountry; at other times, they "herd" fires caused by lightning. Monitoring is key, van Wagtendonk says. "We don't put a blindfold on and look the other way."

Controlled or monitored fires don't actually prevent future blazes because brush and trees grow back. "Nothing will stop 200-foot-high flames," says Timothy Ingalsbee, executive director of Firefighters United for Safety Ethics and Ecology. "But when such a fire does encounter one of those areas where they've done prescribed burns, it'll change its intensity. It'll drop to the ground and allow firefighters to get a handle on it."

Clouds' Rest in Yosemite National Park, shot by Walter Siegmund, Wikimedia Commons, under the terms of the GNU Free Documentation license, Version 1.2

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