Timber industry threatened by unwanted, invasive weed
A $494,000 U.S. Department of Agriculture grant will study how the spread of cogongrass affects Alabama's pine forests. In recent decades the health of many loblolly pine forests in the state and Deep South has been deteriorating, said Stephen Enloe, invasive plant specialist at AU's College of Agriculture.
Forestry is the state's top manufacturing industry, according to the Alabama Forestry Commission. There are about 22.7 million acres of timberland in Alabama, accounting for about 70 percent of the total land area of the state.
"The effects of cogongrass is ecological and economic," Enloe said. "Most of the timberland in Alabama is privately owned. The pine decline has a real impact on the pocketbooks of people who look to their timber as sources of income and retirement."
Enloe said that when cogongrass is left unchecked in an area, it will crowd out native plants. "It grows in dense mats and it burns much hotter than our native grasses, so it creates a fire hazard as well," he said.
Enloe is conducting the research with Nancy Loewenstein, a forest ecologist and invasive plant specialist; Lori Eckhardt, a forest pathologist and entomologist; and David Held, an entomologist.
A native of Asia, cogongrass first was discovered in Alabama in the Mobile area during the early part of the 20th century. It is believed the grass was used in packing materials coming into the Port of Mobile. For decades the noxious weed spread slowly through southwest Alabama and southeast Mississippi, said Stephen Pecot, communication director for the Alabama Cogongrass Control Center.
Then Hurricane Ivan hit the Gulf Coast in 2004. Since then, the grass has spread through the southern half of Alabama and is widespread in Mississippi, Florida and Georgia, according to the Center for Invasive Species and Ecosystem Health at the University of Georgia. Cogongrass also has been found in Louisiana, Texas, Tennessee and the Carolinas, data provided by the center shows.
The recovery and cleanup effort after Ivan brought help, and earthmoving machines, from throughout the region. When those machines returned home, they carried the grass with them to establish new colonies.
Pecot is taking part in a $6.28 million federally funded effort to control and eradicate the grass from the state. The grass covers about 100,000 acres in 32 of Alabama's 67 counties.
Eradication efforts, most often herbicide spraying to kill the grass, will begin in mid-June, Pecot said.
"Cogongrass is very hardy. You just don't spray it one time and walk away," he said. "It will take repeated sprayings over several years to get patches under control and finally kill the roots of the grass."
The threat the grass poses to pine forests is multi-fold, Enloe said.
"We know that cogongrass and the increased risk of intense fires it presents plays havoc on a forest system's natural vegetation," he said. "But no one has looked at whether there's a cascading effect on the species and populations of insects. ...
"We want to find out how cogongrass infestations, as well as the herbicides and other management strategies being used to control the weed, alter insect diversity and abundance (affect) those loblolly pine forests showing symptoms of pine decline."