Forest Thinning Will Increase Wildfire Risk
- by Charles Thomas, The Oregonian
[[{"type":"media","view_mode":"media_large","fid":"232","attributes":{"alt":"","class":"media-image","style":"width: 277px; height: 184px; float: left; margin: 3px 10px;","title":"Photo: AP/The Record Searchlight"}}]]As fires again rage across the West, senators from John McCain, R-Ariz., to Ron Wyden, D-Ore., echo the refrain "thin the forests" to prevent wildfires. Unfortunately, most of the advocated thinning will actually stoke the wildfires of the future rather than lessen their occurrence and impacts.
Thinning prescriptions proposed in Wyden's O&C legislation, designed by eminent foresters Jerry Franklin and Norm Johnson, will stimulate hotter, faster-growing wildfires that are more hazardous to fight. These prescriptions drastically thin forest canopies through timber sales designed primarily to generate timber volume, often leaving the slash and smaller shrubs and trees for non-commercial fire hazard reduction projects that are usually underfunded, unable to match the pace of canopy thinning projects and clear-cuts across the landscape.
Thinning forest canopies opens the stands to more sunlight, which encourages growth of fine fuels, including shrubs, small trees and grasses. Penetration of sunlight and dry summer winds effectively increases the active fire season by drying this new growth and leftover logging slash much faster than in adjacent unlogged forest stands, where greater canopy closure with tall shade columns retains moisture in soils and vegetation.
Active fire season begins weeks earlier in thinned forests and lasts weeks later, drastically increasing the time span during which dry forest conditions contribute to rapid fire spread. These dry, thinned forests often burn hotter and more erratically than unthinned stands, even causing retreat of firefighters when conditions become too dangerous to maintain fire lines.