Fall 2005

Loss of Interior Forest in the Southeast Tied to Economic Development

In an article published fall 2004 in the journal Ecology and Society, Southern Research Station (SRS) researchers David Wear, John Pye, and Kurt Riitters provided a visual forecast of the effects of economic growth on interior forest habitat in the Southeast.

“Almost 90 percent of the land in the Southeastern United States is privately owned,” says Wear, project leader of the SRS Economics of Forest Protection and Management unit in Research Triangle Park, NC. “This means that major land use changes are being shaped by hundreds of thousands of individual decisions. We project that continuing urbanization and low-density residential development over the next decades could have a profound impact on the forest ecosystems in the Southeast.”

Many of the species that thrive in interior forest habitats cannot live in forest edge habitats. “Maintaining the species diversity of a forest means having suitable proportions of edge and interior habitat,” says Riiters, deputy program manager for the SRS Forest Health Monitoring unit in Research Triangle Park, NC. “As development proceeds, edge habitat becomes more plentiful and interior habitat more scarce. For this study, we focused on interior forest as an indicator of available habitat for species that tend to decline when forests become too fragmented.”

The researchers used countylevel data to estimate and model changes in interior forest in a study area that included the 12 States in the Southeastern United States bordered in the north by Kentucky and Virginia and in the west by Texas and Arkansas. Most of these States are still more than 60 percent forested, but 5 are among the top 10 nationwide for rates of urbanization.

The researchers used a sophisticated combination of economic analysis, landcover modeling, fragmentation analysis, and other factors to make their forecasts. As expected, they found that interior forest cover decreases in relation to increases in road density, population density, and household income. Interior forest also decreases as the value of agricultural products and site productivity rise. Forecasted changes, however, were not consistent across the region.

“Our forecasts to the year 2020 show the future loss of interior forest highest in the Southern Appalachian Piedmont of North and South Carolina, with the gulf prairies and marshes in Texas and the Florida coastal lowlands following,” says Wear. “We project that 66 percent of the loss of interior forests will come from urban counties, which indicates the importance of the forests that fringe major cities.”

Seven of the ten metropolitan areas slated to lose the most interior forests are in Florida, with the St. Petersburg-Clearwater area losing 34.5 percent of its interior forest. Columbia (SC), Atlanta (GA), and the Research Triangle area in North Carolina (Raleigh-Durham- Chapel Hill) round out the top 10. Large areas of interior forest loss are also forecast for counties around Knoxville and Nashville in Tennessee, and counties along the Gulf of Mexico from the panhandle of Florida to Louisiana.

“With the exception of the Southern Appalachian Highlands, where a quarter of the land is publicly owned, the future protection of biodiversity in the Southeast will depend on what happens on private land,” says Wear. “The model presented in our article gives us the ability to focus our attention on the areas where biodiversity is most threatened by development and population growth.”

Full text of the article available online at http://www.srs.fs.usda.gov/pubs/21390

For more information:
David Wear at 919–549–4011 or dwear@fs.fed.us

**Correction: In this issue of Compass there is an incorrect link. It should read http://www.srs.fs.usda.gov/pubs/viewpub.jsp?index=21390 instead of http://www.srs.fs.usda.gov/pubs/viewpub.jsp?index=8455