| Abstract | A principal challenge to restoring tree-invaded grasslands
is the removal of woody biomass. Burning of slash piles
to reduce woody residues from forest restoration practices
generates intense, prolonged heating, with adverse effects
on soils and vegetation. In this study, we examined vegetation
responses to pile burning following tree removal
from conifer-invaded grasslands of the Oregon Cascades.
We quantified the longevity and magnitude of fire effects
by comparing ground conditions and the cover and richness
of plant species in burn-scar centers (higher-intensity
fire) and edges (lower-intensity fire) with adjacent unburned
vegetation 7 years after treatment. We interpreted patterns
of recovery through the responses of species with differing
growth forms, habitat affinities, and clonality. Cover of bare
ground remained elevated at the centers, but not at the edges
of scars; however, much of this effect was due to gopher
disturbance. Total plant cover, consisting entirely of native
species, was comparable in and adjacent to scars. However,
richness remained depressed at the scar centers. Cover of
grass, meadow, and non-clonal species was comparable in
and adjacent to scars, but cover of forb, sedge, residual forest,
and clonal species was reduced at the centers. Although
scar centers had a simpler community structure (fewer but
more abundant species) than the adjacent vegetation, they
remained free of exotics and recovered quickly, aided by
the soil-disturbing activities of gophers and the regenerative
traits of native, disturbance-adapted species. Pile burning
can be a viable and efficient approach to fuel reduction in
the absence of exotics.
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