Wrestling with Fire
Through much of the 20th century, a national forest
policy of fight-every-fire led to a vegetative build-up
that has fueled intense and severe fires in the last 30
years, particularly in the arid West. Compared to forty
years ago, the number of major wildfires to occur each
year has increased four-fold, and the area of forest
burned has increased six-fold (National Wildlife Federation 2008).
Prescribed fire is a common tool to reduce fuel loads,
but debates linger over where, when, and how to use
fire to manage forest ecosystems. In the Southern Appalachians, for instance, managers conduct prescribed
fires to reduce fuels such as mountain laurel and
rhododendron. The burns, traditionally done in the
dormant season when cool temperatures and steady
winds make fires easier to control, benefit species that
depend on hardwoods and their hard mast, such as
the red-cockaded woodpecker (Picoides borealis) and
fox squirrel (Sciurus niger).
Recently, however, scientists and managers have
studied burning in the growing season, a time when
lightning would have naturally ignited most fires. A
report by research group Tall Timbers suggests that
limited “lightning-season” burns could boost ideal
habitat, nesting success, and other survival variables
for wild turkeys (Meleagris gallopavo), Bachman’s
sparrows (Aimophila aestivalis), and many other
species (Cox and Widener 2008). One of the report’s
authors, biologist Jim Cox, says ecological support for
the practice is sound, and many managers are already
implementing later-season burns “as another tool in
their toolbox.” Of course, managers must study an
area’s fuel loads in order to assess whether the ecological benefits of in-season burns outweigh the risk
of fire spreading out of control.
Credit: Darren A. Miller
regions of the U.S. has declined
by more than one-third in the
last quarter century (American
Forests). Some conservationists
are therefore turning their attention to preserving the trees that
remain in developing landscapes.
Urban forests “protect us from
the sun, wind, and rain, and clean
the air we breathe and the water we drink,” says Greg
McPherson, a researcher at the USFS Center for Urban
Forest Research. “They are the jewel of our cities.”
Credit: Jim Cox
A warming climate complicates fire management.
As climate shifts, “fire is probably going to be driving [wildlife] range shifts in very punctuated, abrupt
changes,” says Max Moritz, an extension specialist at
the University of California-Berkeley. A single severe fire
could wipe out a forest and displace a population permanently, says Moritz, who recently worked with colleagues
to map out projected fire regime changes under climate
change (Krawchuk et al. 2009). Such models may help
managers plot out and conserve escape corridors—intact
pathways of natural land that wildlife could use to migrate, temporarily or permanently, to safe haven.
Baltimore, Maryland has become a test case for the
importance of urban trees. The Baltimore Ecosystem
Study (BES), funded by the National Science Foundation, found that of all the bird species that appear in the
mid-Atlantic region during the breeding and summer
seasons, fully one-third occur in Baltimore. Furthermore, it’s clear that certain birds associate with certain
types of neighborhoods. Eastern bluebirds (Sialia sialis)
and northern flickers (Colaptes auratus) tend to congregate in older areas with mature trees, while crows
(Corvus brachyrhynchos) and starlings (Sturnus vulgaris) dominate inner city environments (Nilon et al.
in press). The study’s authors hope to give homeowners
information about how they might “manage” their yards
by planting or saving certain types of trees to benefit
various species of birds.
Prescribed burns.
Land managers use
controlled fire (top)
to reduce hardwoods
and regenerate
understory vegetation.
New research shows
that when such fires
are conducted in the
growing season, they
can benefit a variety of
birds such as Bachman’s
sparrows (Aimophila
aestivalis), which
build and hide their
nests within protective
groundcover (above).
Confronting Urban Sprawl
As urban centers swell, they consume and fragment
the forests they displace. Heavy tree canopy in key
Outside major cities, linear forest corridors known as
greenways can offer habitat to many wildlife species
if they are well-designed. North Carolina State Uni-
versity associate professors George Hess and Chris
Moorman have found, for example, that greenways
designed primarily for recreation—with wide paved
paths flanked by strips of mown grass—correlate with
