MILILANI, Hawaii (AP) - Firefighters are battling a fire that has burned hundreds of acres of rare native forest on Oahu. The state Department of Land and Natural Resources said Thursday the Kipapa drainage fire above Mililani Mauka is 30 percent contained. Firefighters don't know when they will have it contained. The fire is burning ohia and koa forest on steep mountain ridges. There are no roads in the area, so firefighters are using helicopters to douse the flames. About 350 acres have burned so far. It's not clear what started the blaze. The fire has burned part of the Oahu Forest National Wildlife Refuge, a nearly 5,000-acre refuge managed by the U.S. Fish and Wildlife Service. The forest provides habitat for native birds, endangered tree snails and threatened and endangered plants.