From: Halpern, C. B., A. L. Lezberg, and R. E. Bigley.
1999. Are effects of broadcast burning on forest
understory communities evident after 40 years of succession? [Abstract].
84th Annual Meeting of the Ecological Society of America, Spokane,
Washington.
Until recently, broadcast
burning of logging slash was a common practice on clearcut sites in the Pacific
Northwest. Moderate to high intensity
burns were used to reduce the potential for future fire, to facilitate tree
planting, and to promote tree growth by removing competing vegetation. Current
prescriptions may involve little or no burning. Here we address the long-term consequences of broadcast burning
for the composition and structure of forest understory communities. We compare data from 44 burned-unburned plot
pairs in ca. 40-yr-old forests representing different geographic regions and
plant associations in western Oregon and Washington. There were few statistically significant differences in species
composition and abundance between burned and unburned plots, although burning
induced subtle changes in community structure.
Woody life-forms (hardwood trees, shrubs, and subshrubs) had lower cover
and herbaceous groups (forbs and ferns) had higher cover in burned plots. Early seral species, which averaged 10%
cover, were nearly twice as abundant in burned plots. Although there were few differences in floristic composition
between plot pairs, several forest species thought to be sensitive to fire
(e.g., Linnaea borealis, Cornus canadensis, and Taxus brevifolia) showed lower average
cover on burned plots. Although
understory composition varied with geographic region and forest type, responses
to burning were similar, suggesting that these effects are general and fairly
predictable.