A wildfire burned unchecked overnight Wednesday through a portion of some of the last remaining intact native forest on Oahu.
By midday Thursday the fire above Mililani Mauka had more than doubled in acreage.
The "pristine" native Hawaiian forest contains sandalwood (iliahi) and the endangered Oahu elepaio, state officials said.
Firefighters Thursday continued trying to halt the spread of the blaze, which began Tuesday night, in the 4,775-acre O‘ahu Forest National Wildlife Refuge.
"It’s been burning in a really pristine piece of native Hawaiian forest," said Lisa Hadway, administrator of the state Division of Forestry and Wildlife, at a news conference Thursday afternoon. "The firefighters were actually smelling the sandalwood burning, which is really, really sad to lose some of the last trees on this island."
The blaze grew to 350 acres by noon Thursday, up from 150 acres Wednesday evening, and was 80 percent contained as of 9 p.m. Thursday.
The fire, burning in a remote area with extremely steep and dangerous terrain, is being fought with aerial water drops, said fire spokesman Kendall Ching.
On Thursday five choppers — four contracted by the U.S. Fish and Wildlife Service, which manages the refuge, and the state Department of Land and Natural Resources — and one from the Honolulu Fire Department scooped 50- to 80-gallon buckets of water from tanks to douse the flames.
The Fish and Wildlife Service is contributing federal funds for the helicopters.
HFD’s helicopter was not available Wednesday as it was tied up with ocean rescues due to high surf.
The refuge is home to 22 federally listed endangered species of flora and fauna, including the endangered pupu kani oe (Oahu tree snail), many native birds including the elepaio, iiwi and pueo, as well as several endangered plants.
"We’re all working together to … not only protect habitat for these really unique species, but it also protects critical watershed area as well," Hadway said. "Often when native forest is burned, it never recovers. It usually is replaced with weeds that often burn more easily in the future."
She added it could contribute to runoff, which would eventually end up in the ocean.
Hadway said that in Hawaii, "as a percentage of acreage burned every year, we’re actually on par with the Western states."
She said the number of fires over 100 acres has significantly increased in the last decade.
"With these drier weather conditions, and the prospectus of climate change and global warming, we’re looking at more fires in the future," Hadway said.
The forestry division has trained wildland firefighting crews, but, because of the remote location, the only access was by helicopter.
"There was very little we could do," said Rob Hauff of the forestry division. "We tried to cut some fire lines, but the terrain was extremely steep and dangerous."
Hauff said the lack of wind for the last couple of days was helpful, but the lack of mauka showers was not.
"Hopefully the tradewinds will return and the mauka showers will help," he said.
Forestry personnel cut a landing zone Wednesday for the helicopter in the remote area.
Five miles away in Mililani, HFD firefighters kept water in portable ponds for the helicopters.
Hauff said the only thing that may be helpful in fighting this fire would be the use of larger helicopters that could haul 1,000- to 1,500-gallon buckets of water, rather than the small helicopters currently in use.
He said the state has been in discussions with military officials about the fire but has not requested any assistance yet. The cause of the fire is unknown.
