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.
This article appeared in the print edition of the magazine with the headline Fire was not catastrophic.
Republish our articles for free, online or in print, under a Creative Commons license.
