SAVANNAH — Firefighters used hand tools to battle a slow-moving wilderness fire Thursday on Cumberland Island, forcing the National Park Service to close portions of the federally protected island to tourists visiting the Georgia coast.
    After burning for more than a day, the fire covered 45 acres — or less than 1/10th of a square mile. That's a tiny fraction of the land on Georgia's largest barrier island, which covers 40,000 acres. It's mostly wilderness but is also home to a few historic 19th-century mansions built by wealthy industrialists such as Thomas Carnegie, who owned Cumberland Island before the federal government bought it in 1972.
    Maggie Tyler, a Park Service spokeswoman working on the island, said two wilderness camp grounds nearest the fire had been closed. However, visitors were still being allowed to arrive by ferry and van tours along the island's main road were continuing uninterrupted.
    "It's not a fast moving fire, so it's kind of easy to keep it where it is," Tyler said. "...On the main road or on the beach, you would see smoke but not see any flame."
    The fire posed no immediate threat to any of Cumberland Island's historic structures. Tyler said the nearest, the Carnegie family's Victorian mansion called Plum Orchard, was 2 ½ miles from the blaze. The tiny First African Baptist Church, where John F. Kennedy Jr. married Carolyn Bessette in 1996, is several miles farther north.
    The fire was first spotted early Wednesday and investigators were still working Thursday to determine what caused it. Tyler said periodic fires are crucial to maintaining the island's longleaf pine forests, though this particular blaze wasn't planned.
    About 16 firefighters were working Thursday to dig fire breaks in a circle around the blaze by clearing away pine needles and other fuels using hand tools. Some also carried water pumps in backpacks to hose down smoldering hotspots that could otherwise cause the fire to grow.
    Fred Boyles, park superintendent for Cumberlanfd Island, said in a statement that areas would remain closed to the public as long as the fire posed a potential threat. He urged anyone visiting the island to check with rangers for the latest closures affecting hiking trails and campgrounds.
    "The fire is dynamic and trail closures may change rapidly," Boyles said.
    Cumberland Island is accessible from the mainland only by boat. Tyler said the fire was not considered enough of a threat Thursday to justify bringing in firefighting bulldozers or to use helicopters to drop water on the blaze — both of which can be destructive to the island's protected wilderness.
    Cumberland Island gets about 43,500 visitors each year, with visitation limited to a maximum of 300 people per day.
    Winter tends to be much slower. Tyler said only 35 people boarded the ferry to the island Thursday morning.