By Helen Fosgate
hfosgate@smokey.forestry.edu
Since the first Europeans arrived in the Southeast more than 400 years ago, longleaf pines, the original forests of much of the South, have been in steady decline. Cleared for home sites and agriculture, grazed by hogs and cattle, tapped for tar, rosin and turpentine and logged for sawtimber,
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the longleaf gradually gave way to cities, suburbs, farmland--and other pines like the loblolly.
Fire suppression practices also hurt the longleaf, shifting their forest structure from patchy, open stands to those with a closed canopy of hardwoods and shrubs that discourage understory plants. Cecil Frost, a plant conservationist in North Carolina’s Department of Agriculture, calls the “spectacular failure of the primeval longleaf forest to reproduce itself after exploitation a milestone event in the natural history of the eastern United States.”
“People get so upset over the destruction of the rain forests,” says Tim Harrington, a forest ecologist in UGA’s Warnell School of Forest Resources. “But you never hear anything about the loss of millions of acres of longleaf pine, which was every bit as unique and valuable.”
Longleaf pines once thrived on the coastal plain from Virginia to central Florida and westward to east Texas. Unbroken except along major rivers and uplands, the forest sheltered hundreds of species, many of which are now rare, threatened or endangered. William Bartram, in his travels through the South in the late 1700s, described “a vast pine forest of the most stately pine trees that can be imagined.”
Only a small percentage of that old forest survives today in scattered pockets across the South. But Harrington and other researchers are involved in new efforts to restore and manage longleaf pines--and the wiregrass communities that support rare species like the gopher tortoise, indigo snake and red cockaded woodpecker.
“Private landowners now have new incentive through the Conservation Reserve Program to plant longleaf,” says Harrington, “though it’s important to plant them on appropriate sites. They need sandy, well-drained soils. And above the fall line, they are more susceptible to damage from ice storms.”
In addition to providing wildlife habitat, Harrington says, longleaf pines are also more resistant to common diseases like fusiform rust and insect pests like the southern pine beetle. They also produce superior pinestraw and lumber, though they grow a little slower than some other southern pines.
Where wildfires have been allowed to burn and kill competing hardwoods and pine seedlings, longleaf stands support a myriad of grasses and other herbaceous species, and Harrington is looking at the factors that limit plant diversity in planted stands. Is it a lack of light in the understory? Competition for water and nutrients? Or is the thick fall of pine needles a more inhibiting factor? “It’s important to know,” says Harrington, “because without restoring the understory, you’ve only got a piece of the pie.”
In a study funded by the USDA Forest Service, Harrington set up experiments in six research areas on the Savannah River Site near Aiken, S.C. He’s comparing growth rates of grasses and other understory plants in thinned and unthinned longleaf stands 15 to 18 years old. He’s using trenches lined with aluminum flashing to eliminate root competition between overstory pines and the container-grown understory plants. At some sites the pinestraw is removed each month. At others it’s left to build up on the ground.
“Preliminary results are surprising,” he says. “Light is not nearly as important as we had originally thought. Instead, we’ve found below-ground resources like water and nutrients play a more significant role in the health of these understory communities. The results will help us to identify treatments that encourage a species-rich understory of herbaceous plants.”
Research continues here and elsewhere in the Southeast. In fact Harrington says there is growing interest in longleaf pines among landowners and conservationists. And, he says, the Forest Service is also interested in the benefits of restoring longleaf forests on public lands for recreation and wildlife habitat as well as timber production. |
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