A Southern Forest Story

Soil Opens Window to the Past and the Future

by Scottee Cantrell

In a South Carolina forest, where deer wander through stands of loblolly pines grown tall in old cotton fields, the land is eroded and gullies sometimes run deep. Cotton farming depleted and degraded the soil by the 1920s, so that when you step in some forest areas today, it is the subsoil that your foot touches. The topsoil - some experts say as much as six inches from Virginia to Georgia - was carried off downstream leaving behind fields too eroded to farm and rivers filled with sediment.

The soil that remains underneath the South’s pines and hardwoods has an important story to tell about the history of old Southern agriculture and about modern rapidly growing forests and their sustainability, says the Nicholas School’s Daniel D. "Dan" Richter. But to fully understand this story, there have to be permanent soil plots like those at the Calhoun Experimental Forest in South Carolina, where repeated sampling has been conducted for four decades, and for which a soil archive contains nearly all samples collected and carefully stored for periodic analysis.

"There are a number of long-term studies of forest change, but practically none of these include observations of how soils change through time," says Richter, professor of forest soils and ecology.

Richter credits Dr. Carol G. Wells of the U.S. Forest Service for originating the Calhoun study in 1957 and for continuing it through 1982. The site, located in a remote area of upstate South Carolina near Spartanburg, was originally an old cotton field that Wells’ colleagues planted in pine, a very common practice in the mid-20th century.

When Wells retired, Richter expanded the Calhoun soil archive with help from his students. The archive is stored in a striking oak cabinet that dominates a second floor hallway at the Duke’s Levine Science Research Center. Behind its doors are drawers labeled by year – starting in 1962 and continuing through 1997 at about five-year intervals – each containing dozens of little jars that together tell a forest history.

Although he speaks softly, it is with a great deal of enthusiasm that Richter talks about the richness of the Calhoun project, one of the world’s longest soil studies, and the important part it can continue to play in providing new insights into soils, forests, and history.

• The site, for example, is an ideal laboratory for observing effects from acidrain."Whereas most environmental studies have modeled acid rain effects on soil with few if any field observations, we have coupled our soil-chemistry models with direct observations of soil acidification to better understand the acid dynamics of a forest," says Richter.

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