"Although prescription burning has proven to be a viable means of reducing fire hazard in some forest types, it is not appropriate for the boreal forests of Canada and the chaparral shrublands of southern California," says Jon Keeley of the USGS in Sequoia-Kings Canyon National Parks, Three Rivers, California. Keeley and other researchers explore fire management in five papers in the December issue of Conservation Biology.
The idea of using prescribed burns to reduce large, intense forest fires throughout the western U.S. came from studies of yellow pine forests in the interior West, such as northern Arizona. Historically, these yellow pine forests had frequent surface fires that resulted in an open-canopy mosaic of old and young stands of trees. Fire suppression led to an unnatural buildup of small trees, and dead branches and needles on the forest floor, which then fueled catastrophic crown fires.
But although prescribed burning makes sense for these yellow pine forests, the management technique is not warranted everywhere in the West. Notably, prescribed burning fails to reduce crown fires in closed-canopy forests and shrublands, where large, intense fires are natural and burn through young and old stands alike, says Keeley. Moreover, prescribed burning can have adverse ecological consequences in closed- canopy forests and shrublands. For instance, when prescribed burns are more frequent than the natural fire regime, they can outstrip native species' ability to recover and so lead to local extinctions.
One example of a closed-canopy forest where the "ye
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Contact: Jon Keeley
jon_keeley@usgs.gov
559-565-3170
Society for Conservation Biology
30-Nov-2001