Firefighters are battling flames that have burned more than 100 acres of the Greenwood Forest Wildlife Management Area in southern New Jersey. The state Forest Fire Service says the fire in Manchester Township was reported Sunday morning. Officials say the flames are not threatening any homes or businesses. But drifting smoke has forced the closure of a stretch of nearby Route 539. The cause of the fire has not been determined, and it wasn't clear Sunday afternoon if the fire would continue to spread. The Greenwood Forest site spans about 29,000 acres, mostly in Ocean County.