The Wildlife Professional - Spring 2010 2009

lower bird diversity and fewer sensitive species such as downy woodpeckers (Picoides pubescens) and indigo buntings (Passerina cyanea) (Hull 2003). On the other hand, wider greenways with more natural growth of trees and underbrush attract neotropical migrants and, Hess hypothesizes, may be associated with increased snake diversity (Kohut et al. 2009).

Practicing Adaptive Forestry Wildlife managers across North America are working with forestry experts to adopt regionally tailored on-the-ground measures that can help sustain healthy, productive forests and, at the same time, support forest-products industries and benefit wildlife. Among the primary approaches:

Support variable structure. Forest structure—the top-down layers of canopy, snags, young trees, under-

Tailored
management.
To help ensure
nesting success for
red cockaded wood-
peckers (Picoides
borealis), a U.S. Fish
and Wildlife Service
employee erects a
nest box (above right).
By banding and track-
ing newborn birds
(above left), biologists
are learning that
careful forest man-
agement is improving
the odds for these
endangered birds.

brush, and leaf litter—is critical to the
survival of many species. Timber har-
vest, however, often tends to simplify
forest structure to the detriment of
wildlife. Pine martens (Martes mar-
tes), for example, a state-endangered
species in Wisconsin, rely on downed
debris to find their rodent prey, and on hollowed-
out but still-living trees to hide from predators, keep
warm, and bear young. Recognizing the need for
variable structure, Wisconsin forest management
guidelines now recommend that conifers be retained
as “significant structural components,” preferably in
clumps to boost seed production. Retaining conifers is
valuable because they are associated with several war-
bler species and raptors, as well as with pine martens
and other boreal species at the southern extent
of their range.

Credit: John and Karen Hollingsworth/ USF WS Credit: USFS

Conduct strategic clearcuts. For five to 20 years after an area has been clearcut, it may provide thick

ground cover that is ideal habitat for certain wildlife species. Ruffed grouse, for example, use the growth in clear-cut areas to escape from predators, nest, and rear young (Harper et al. 2006). Yet clearcuts also eliminate trees producing hard mast (acorns and nuts), which are important food sources for forest species like grouse and deer. Managers are learning to compromise. In eastern forests, for example, some managers have turned to the shelterwood system, a type of cut that leaves a small amount of mast-producing trees standing after an initial harvest. The “leave” trees may then be cut several years later, after the first cut areas have begun to regenerate. Early studies on small mammals and other species have shown that shelterwood cuts have no negative effect on wildlife populations, and may even boost populations (von Trebra et al. 1998). In the western U.S., managers on public lands pursue a similar strategy, creating small openings in the forest canopy to replicate natural disturbances and allow pine trees to regenerate.

Study shifts in succession. Researchers have long understood that different wildlife species inhabit forests at various stages of succession—the natural replacement of animal and plant species in an area over time. Recent studies, however, show that some old patterns may be shifting. Wildlife species once strongly associated with mature forests, such as ovenbirds (Seiurus aurocapillus) and worm-eating warblers (Helmitheros vermivorus) have been shown to use regenerating clearcuts in the post-breeding season (Vitz and Rodewald 2006). “The juveniles and adults move into these successional habitats presumably to use the thick cover as protection from predators or to eat the abundant fruits,” says Amanda Rodewald, associate professor of wildlife ecology at Ohio State University’s School of Environment and Natural Resources. Land managers can use such knowledge to structure suitable habitat.

Seeking a Sustainable Future On a global scale, nations increasingly recognize that sustainable forestry balances the world’s need for forest products with the necessity for forest health and biodiversity. At the 1992 United Nations Earth Summit in Rio de Janeiro, participants including 172 governments and 2,400 non-governmental representatives created a document informally referred to as “Forest Principles.” The principles included non-legally binding regulations that addressed illegal logging and deforestation as well as the need for independent certification programs to regulate trade in wood and wood products.