Fire was not catastrophic

  Dear HCN,

The March 6, 1995 edition of HCN contained several articles on fire, and most were well-balanced and informative. Unfortunately, one article, "After the fire comes the real devastation," contained significant inaccuracies that may have misled some of your readers. Much of the focus of the article was on an erosional event that occurred in the headwaters of the South Fork of Sheep Creek, Idaho, on July 31, 1994. We are both scientists who have worked in this drainage.

The drainage and erosional event is a poor example from which to extrapolate about fire and erosion risks throughout the Intermountain West. No evidence exists to suggest that vegetation structure (primarily subalpine fir and whitebark pine) has been altered by management practices. The forests that were burned in the headwaters are not the mixed conifer stands that recent forest health initiatives have suggested are unhealthy.

Similarly, the erosional event was not mysterious and the formation of hydrophobic soils not "freakish." Contrary to the tone of Tom Knudson's article, the formation of hydrophobic soils is a well-documented phenomenon that occurs as a result of volatilized organic compounds condensing in some soil types to create a layer of reduced permeability. Neither the creation of hydrophobic soils nor accelerated erosion after fires is new or unnatural. Sediment deposits exposed along the channel suggest that similar events have been occurring since before European settlement of North America.

The fire and its aftermath clearly killed fish throughout several watersheds and may influence the distribution and dynamics of fish populations for years to come. All evidence suggests, however, that populations (including bull trout) are recovering quickly. Recent work also indicates that no bull trout were present in the South Fork Sheep Creek (a small tributary to the larger Sheep Creek), thus no rare spawning population of bull trout went extinct as described in the article. Erosional events similar to the one in the South Fork have undoubtedly occurred and will continue to occur in drainages with bull trout and other aquatic species. Such events are probably not an uncommon component of the disturbance regime these species have evolved and persisted with through time.

These clarifications may seem minor when considered individually, but in aggregate, they suggest that no catastrophe occurred. The alteration of watersheds by chronic land-use disturbances such as roading, timber harvesting, mining, and grazing may be a greater risk to aquatic and riparian ecosystems.

Alan Barta, Eagle, Idaho, and

Bruce Reiman, Boise, Idaho

Alan Barta is a research geomorphologist and Bruce Reiman is a research fisheries biologist. Both work for the Forest Service, but they write this as individuals and are not speaking for their employer.

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