By William L. Baker, Guest Commentary
The Denver Post
Copyright 2006 The Denver Post
All Rights Reserved
LARAMIE, Wyo. — Congress is considering legislation that would facilitate logging and planting after forest fires or other large natural disturbances (Senate Bill 2079), but from the standpoint of ecological science this legislation is misdirected and warrants rejection. In Colorado, post-fire logging after the Missionary Ridge and Burn Canyon fires created considerable controversy.
Recently I was one of five fire ecologists who completed a scientific review of management of forests subject to fire in the Western United States, commissioned by the Society for Conservation Biology.
Our review concludes that logging and planting after fires slow natural forest recovery, adversely affect biological diversity, and may temporarily increase fire risk. Some wood may be obtained by post-fire logging, but the ecological costs are high. Our forests are remarkably capable of recovering from even severe fires, but after a fire is an ecologically poor time to cut wood or drive equipment across slopes.
Post-fire landscapes have substantial capacity for natural recovery, but post-fire logging and planting amount to a tax on natural recovery processes. Natural recovery is greatly enhanced by post-fire structural legacies (e.g., surviving damaged trees, dead wood) that logging typically removes.
Damaged trees that survive even a short time after fire are key seed sources that promote forest recovery. A recent publication in the journal Science showed that post-fire logging directly destroyed a large fraction of naturally regenerating small trees, reducing natural reforestation. Dead wood, including large snags and logs, is second only to live trees in importance to recovery, reducing erosion, providing habitat for organisms that enhance recovery and replenishing soil nutrients. It makes no sense, ecologically, to remove dead trees that naturally hold soil in place and provide partial shade while the forest recovers from fire.
Roads necessary for logging are often a primary source of increased sedimentation into streams and lakes after fire, slowing natural recovery of fisheries and other aspects of aquatic ecosystems. Roads and equipment used in logging also commonly bring in non-native, invasive species.
Natural, undisturbed, post-fire habitat is now among the rarest habitat in Western forests, even though it is usually very high in native species diversity after a few years of recovery.
Post-fire logging does not reduce the potential for subsequent fires, but instead, in the short term, increases fire risk.
Too often non-native species, particularly flammable grasses, have been directly planted in an attempt to decrease erosion, but these grasses are often more flammable than recovering native plants. Increased flammability also occurs because post-fire logging removes large wood, leaving behind limbs, twigs, and needles that are smaller and thus more flammable. Logging rapidly concentrates these fine flammable fuels at the soil surface, where they would normally accumulate slowly. Removal of partial shade from dead trees and scattered surviving green trees lowers moisture in these fine fuels, adding to increased fire risk. Prescribed burning could reduce this enhanced risk, but may damage or kill regenerating trees and other recovering organisms, slowing recovery further.
Senate Bill 2079 warrants rejection from an ecological perspective. It would not hasten, but slow restoration of habitat temporarily lost to fires and other natural disturbances. Right after a fire or other disturbance, there is usually little ecological need for haste. Forests, just like people, can recover well after disturbance if given rest and proper care, not more disturbance.
Dr. William L. Baker is a professor at the University of Wyoming who teaches courses on fire and landscape ecology.