Review and download Chapter 3 - Golden-winged Warbler Working ...

potential to become large-diameter in future
rotations or retain clusters of small trees to
provide some structural diversity. For basal areas
less than 10 ft 2 /ac (2.3 m 2 /ha), residual trees
should be dispersed throughout the stand or
retained in clumps embedded within the harvest.
At basal areas >35 ft 2 /ac (8.0 m 2 /ha), up to half of
the residual trees should be spatially aggregated
in patches and the remainder dispersed
throughout the stand.
In the Appalachians, use of timber harvesting
followed by burning extends the
habitat availability of forest stands for
Golden-winged Warblers by sustaining
Mechanical Clearing
Mowing and brush-hogging during the
non-breeding period is another
method to reduce woody growth to
maintain Golden-winged Warbler
habitat. Cutting of woody brush
stems; however, tends to stimulate
woody re-growth from the established
roots, which may limit the subsequent
period of habitat availability.
Following the cutting with a selective
herbicide application will often be
necessary to reduce re-sprouting.
Cutting should be conducted in
patches to maintain the patchy woody structure
that Golden-winged Warblers prefer. Cuttings in
Minnesota brushlands may reduce quality of
breeding habitat for at least three years relative
to unmanaged areas though no mention was
made about the size and configuration of the cut
areas (Hanowski et al. 1999). Thus, where the
effect of mechanical cutting is not well
understood, it is advised to incrementally
increase the ratio of brush cleared and to
evaluate Golden-winged Warbler response at
each cutting interval. Residual canopy trees or
clusters of shrubs and saplings should be retained
when present (Figure 3—20). On wet sites and
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herbaceous cover (Brose and Van Lear 1998). This
practice has been used in the Midwest to
promote Sharp-tailed Grouse habitat, particularly
in diverse barrens (a combination of herbaceous
prairie and brush prairie with 30–60% woody
cover) that attract low densities of Goldenwinged
Warbler (Mossman et al. 1991). When
these areas are burned on longer rotations,
succession leads to more woody vegetation
dominated by aspen, oak, and jack pine and an
associated increase in Golden-winged Warbler
abundance.
Figure 3—20. This area was mechanically treated in Bald Eagle State Park,
Pennsylvania to create breeding habitat for Golden-winged Warbler and
American Woodcock. Note residual canopy trees and clumpiness of uncut
saplings and shrubs. Photo by Jeffrey Larkin.
sensitive soils, heavy equipment should be used
only when the ground is frozen.
Mechanical cutting is generally a non-commercial
treatment though the number of bioenergy and
biofuel plants capable of utilizing woody biomass
is increasing such that this may be a commercially
viable option in some regions. Mowing may also
be necessary to reduce vegetation height in
shrubland habitats where fire has been excluded
(Figure 3—21). Mechanically lowering this
vegetative fuel load may allow managers to
reintroduce fire as a disturbance factor in
Golden-winged Warbler habitats.