Fall 2005

What Can Experimental Forests Teach Us Fragmentation?

Since the 1920s, the USDA Forest Service has maintained a system of experimental forests to test hypotheses and collect longterm data about the ecological effects of fire, grazing, insect infestations, air pollution, and other disturbances. In the South, researchers from Federal agencies and universities use 15 active experimental forests for studies ranging from the practices needed to maintain healthy forests, to the water fi ltration functions of forests, to habitat restoration for endangered species.

Experimental forests are some of the few places in the United States where longterm data are collected about forests and how they change over time. These living laboratories also serve as demonstration sites where cooperators and landowners can see the results of different forest management options.

In the early 1900s, Southern Appalachian forests were extensively grazed by livestock. Steep mountain land was cleared and planted with corn. Logging was done with little regard for erosion from roads and skid trails. Such land was not wanted by private individuals and could be bought for delinquent taxes.

In 1933, the USDA Forest Service established the Coweeta Hydrologic Laboratory for a program of watershed management research. Early studies on erosion control and soil stabilization for roadbanks and abandoned agricultural land led to the realization that further work required complete watershed instrumentation to provide continuous measurements of stream flow and precipitation. An intensive program of weir construction began at Coweeta in 1934 along with a network of 56 rain gages, numerous groundwater wells, and meteorological stations.

Over the next 80 years, scientists conducted a variety of watershed experiments at Coweeta. Early studies documented the harmful effects of mountain farming, woodland grazing, and unrestricted logging. Water-yield experiments measured stream flow responses to complete or partial forest cuttings and conversion from one type of cover to another. The knowledge from these early experiments became the basis for tests on intensive multiresource management of forests and provided guidelines for watershed management and best management practice standards for public and private forests. Later experiments introduced improved methods of cable logging and forest road design for managing steep mountain lands to minimize damage to soil and water.

Coweeta’s early emphasis on how land management practices affect the hydrologic cycle has evolved into a broader context that examines ecosystem processes of water, carbon, and nutrient cycling at watershed scales. Based on the legacy of information dating back to the 1930s, the research combines short-term experiments and long-term measurements to determine how a range of terrestrial and aquatic ecosystem processes respond to management practices, natural disturbances, and the atmospheric environment. The goal is to identify practices that mitigate impacts on soil chemistry, aquatic life, terrestrial mammals, insects, and plants, and forest succession, growth, and health.

This long-term research within the Coweeta basin provides fundamental information on the structure and function of managed and unmanaged forest ecosystems in the Southern Appalachians. Although most studies take place within the Coweeta basin, several new study sites have been installed throughout the region to address larger scale issues such as forest fragmentation and other consequences of land use change. The centerpiece of the cooperative effort is the Long-Term Ecological Research Program (LTER) with the University of Georgia, begun in 1980 and funded through the National Science Foundation. Coweeta is one of 26 LTER sites in the United States.

The new regional studies focus on characterizing historic, contemporary, and future land use patterns and understanding the impacts of land use change on terrestrial and aquatic resources. In addition to Coweeta scientists, the research involves cooperators from the University of Georgia, Virginia Polytechnic Institute and State University, Duke University, Mars Hill College, University of North Carolina at Asheville, University of Minnesota, and University of Wisconsin-Madison. Study sites outside Coweeta are located on the Little Tennessee River and the French Broad River basins.

These studies examine human land use choices as the primary disturbance on the private lands that cover approximately 55 percent of the Southern Appalachians to address the following questions:

How does land use change interact with environmental change to alter diversity and ecosystem processes?

How are land use decisions influenced by social, economic, and ecological factors?

Can future land use patterns and ecological consequences be predicted by understanding relationships among socioeconomic factors, land use change, and ecosystem structure and function?

The long-term research information from the Coweeta basin provides the “benchmark” for characterizing the impacts of forest fragmentation and other consequences of land use change on watershed resources.

Jim Vose, ecologist at Coweeta for the last 18 years and project leader since the retirement of the legendary Wayne Swank in 1999, sees these new studies as an excellent opportunity to continue serving the people of the Southern Appalachians. “Coweeta has a stellar group of scientists on staff representing the full range of biological and physical disciplines, joined by economists and social scientists from the best universities in the country,” he says. “With the long-term data, rigorous methodologies, and indepth understanding of ecosystem structure and function that have made Coweeta famous, this team is poised to provide credible information that can have a positive impact on the mountains that we all love.”

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For more information:
Jim Vose at 828–524–2128, x 114 or jvose@fs.fed.us