forestry
Ecological Forestry
iNTegRaTiNg DiSTuRBaNCe eCOlOgy PaTTeRNS iNTO FOReST TReaTMeNTS
By R. gregory Corace iii, Ph.D., and P. Charles goebel, Ph.D.
can be agents of disturbance simply by mechanically
altering forest structure or attempting to influence the
severity or magnitude of natural disturbances.
R. Gregory Corace
III, Ph.D., is Forester
and Ecologist at
the Seney National
Wildlife Refuge
and Kirtland’s
Warbler Wildlife
Management Area.
Credit: laurie Tansy
Forty years ago the Kirtland’s warbler (Dend- roica kirtlandii)—a neotropical migrant that breeds in young jack pine (Pinus banksiana)
forests—was on the brink of extinction. Concerted
recovery efforts by federal and state land managers in the northern Lower Peninsula of Michigan
brought the species back from the brink (Probst et
al. 2003). However, this success has come at a cost:
Recovery efforts aimed at producing breeding habitat have resulted in relatively simplified landscapes
and forest stands, to the detriment of some ecosystem functions and wildlife species.
P. Charles Goebel,
Ph.D., is an Associate
Professor of
Forest Ecosystem
Restoration and
Ecology in the School
of Environment and
Natural Resources
at The Ohio State
University.
Credit: Ken Chamberlain
Unfortunately, this pattern of ecosystem sim-plification has too often been repeated by forest
managers. In the zeal to accomplish highly focused
population-based or commodity-based objectives,
forest management has at times ignored underlying ecological principles and disturbance patterns
(Holling and Meffe 1996).
Following Nature’s Lead
A contrasting approach to wildlife habitat manage-
ment is predicated on understanding ecology—the
capabilities of land as determined by landscape posi-
tion, soils, and changes in vegetation due to natural
disturbances—and then managing wildlife habitat
within this context. A “disturbance” is an agent of
change that shapes an ecosystem over time in a
dynamic manner, such as wild-
fires, wind events, floods, insects,
and disease. Land managers, too,
Fortunately, natural and human-caused disturbance
regimes can be integrated into forest wildlife habitat
management, thereby addressing the issues of land
stewardship (Leopold 1949). Once known as “New
Forestry” (Franklin 1989), this ecological approach
to forest management bases actions on the underly-
ing disturbance regime of a given ecosystem, recovery
periods between disturbance events, and resulting
vegetation patterns, which are of special interest to
managers of forest wildlife habitat. Ecological forestry
does not attempt to maximize the productivity of any
single commodity, amenity, or species. Instead, it
allows for multiple goals—improved wildlife habitat,
carbon sequestration, soil stabilization, water filtration,
and economic gain—thus enabling forest conserva-
tion and restoration across various ecosystem and
ownership types (Sarr et al. 2004). The key is linking
site conditions and natural disturbance regimes with
silvicultural treatments that emulate the outcomes
of natural disturbances (Seymour and Hunter 1999,
Franklin et al. 2007). Fortunately, many texts (e.g.,
Frehlich 2002) outline the natural disturbance ecology
patterns of various forest ecosystems, providing useful
background for forest managers.
Credit:
Mike McDowell
In pine-dominated landscapes of northern
Michigan and elsewhere in the Upper Midwest, fire suppression or fire intervals that
poorly emulate the historical range of variation have degraded the ecological integrity
of many forests (Schulte et al. 2007). These
changes have led to declines in the distribution and abundance of many fire-dependent
pine-dominated ecosystems, from the
openland-dominated jack pine barrens to
Credit: R. gregory Corace iii
an aerial view of the structural patterns of jack pine stands in the
Kirtland’s Warbler WMa reveal markedly different management
strategies. The foreground shows a plantation managed intensively
for Kirtland’s warblers, with diamond-shaped openings created by the
“opposing wave” pattern of planting jack pine seedlings after a clearcut.
The area at center shows patterns resulting from a prescribed fire.
Warblers (inset) breed in both of these managed areas, but the patterns
in the burned stand emulate those of wildfires more closely.
