Although the Northwest Forest Plan (NWFP) significantly reduced cutting of old-growth forests on federal land, forests in the driest regions are now at greater risk of being lost to wildfire than to logging. A team of federal and university scientists recently completed a study and analysis of large-diameter forests and discovered that elevated fire levels in the Pacific Northwest outweighed harvest reductions in the loss of older forests.
"Fire is a more important factor of loss to old-growth than harvesting between 1993 and 2002," says Tom Spies, a research ecologist and co-author on a study on the dynamics of older forests. The study, which was published in the journal, Ecosystems, concludes that although the NWFP helped stabilize the number of large-diameter forests in the Pacific Northwest, fire was the main reason for loss of these forests.
The study, The Relative Impact of Harvest and Fire Upon Landscape-Level Dynamics of Older Forests: Lessons From the Northwest Forest Plan, examines western Oregon and Washington and parts of the range of the northern spotted owl. The team used a 30-year satellite record to identify trends in the loss of large-diameter trees—on private and public land—to harvest and fire. They hope their findings may assist managers and policymakers who are trying to conserve older forests and the species that depend on them.
Spies, who is with the Forest Service's Pacific Northwest (PNW) Research Station, says the findings show that among other things, harvesting of older forests on private lands did not increase as some expected. "The protection of old-growth on federal land didn't result in increased rates of harvest of older forest on non-federal land," he explains. "Some had thought that harvesting of older forests might increase on private lands in response to reduction in harvest on federal lands. Even if the [NWFP] had been implemented as intended, a considerable amount of old growth would have been protected, even though some would have been lost to harvest."
Other conclusions listed in the paper are:
- Other studies indicate that warmer springs and summers and earlier snowmelt contribute to the dry conditions that produces more fires in the West. These factors may have contributed to the fires that burned up the old forests during the last decade.
- The Government Accounting Office says that money appropriated for fuel treatments (1999 to 2003) has instead been used to fight fires.
- Comprehensive landscape-level plans will be needed to reduce risk of loss of older forests to fire.
- Federal managers should consider increasing fire prevention and suppression treatments in dry regions as climate change may lead to more fire.
Other members of the research team are Sean Healey, Rocky Mountain Research Station, Forest Service; Warren Cohen, PNW Research Station, Forest Service; Melinda Moeur, PNW Region, Forest Service; Dirk Pflugmacher, Oregon State University; M. German Whitley, PNW Research Station; and Michael Lefsky, Colorado State University.
The above story is based on materials provided by USDA Forest Service, Pacific Northwest Research Station. Note: Materials may be edited for content and length.
- Healey et al. The Relative Impact of Harvest and Fire upon Landscape-Level Dynamics of Older Forests: Lessons from the Northwest Forest Plan. Ecosystems, 2008; 11 (7): 1106 DOI: 10.1007/s10021-008-9182-8
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