“It was a really beautiful native forest,” said JC Watson, director of the Koolau Mountains Watershed Partnership, which helps care for the land. He recalled that it contained uluhe ferns, which often dominate Hawaii’s rainforests, and koa, the wood of which is traditionally used to make canoes, surfboards and ukuleles.
“It’s not a complete burn, but the landscape looks pretty similar to the moon,” Watson said.
The fact that this fire occurred on the wetter, windward side of Oahu is a “wake-up call to all of us that a change is underway,” said Sam ‘Ohu Gon III, senior scientist and cultural advisor at The Nature Conservancy in Hawaii.
The fire primarily burned inside the Oahu Forest National Wildlife Refuge, which is home to 22 species listed as endangered or threatened by the U.S. government. They include the iiwi and elepaio birds, a tree snail called pupu kani oe, and the Hawaiian hoary bat, also known as the opaepea. The U.S. Fish and Wildlife Service, which runs the refuge, does not yet know what plants or wildlife may have been damaged or injured by the fire, spokeswoman Kristen Oleyte-Velasco said.
The fire has incinerated 6.5 square kilometers since it was first spotted on October 30 and was 90% contained as of Friday. Authorities were investigating the cause of the fire about 20 miles (32 kilometers) north of Honolulu.
The flames left gaping dark spots amid a thick green blanket where the fire was not burning. The blackened skeletons of trees protruded from the charred landscape.
The burned area may seem relatively small compared to wildfires in the continental United States, which can level hundreds of square kilometers. But Hawaii’s intact native ecosystems aren’t large to begin with, especially on small islands like Oahu, so even limited fires have far-reaching consequences.
A major concern is what plants will grow in place of the native forest.
Hawaii’s native plants evolved without facing regular fires, and fire is not part of their natural life cycle. Non-native plants that grow faster and contain more seeds tend to germinate instead of native species later.
Watson said an Oahu forest near the last fire contained uluhe ferns, koa and ohia before a fire burned less than a square mile of it in 2015. Now the land has invasive weeds which are more prone to fire, and some slow-growing koa. .
A much larger fire in 2016 in the Waianae Mountains, on the other side of Oahu, destroyed one of the last remaining populations of a gardenia, a rare tree, Gon said.
There are cultural losses when native forest burns. Gon recalled an old story from central Oahu about a warrior who was thrown off a cliff while fighting an enemy leader. His fall was stopped by an ohia tree, another common plant in the cremated area. The feathers of Hawaii’s forest birds were once used to make capes and helmets worn by chiefs.
Watson’s organization is coordinating with the Fish and Wildlife Service to conduct initial damage surveys. They will develop a restoration plan that will include controlling invasive species and planting native species. But there are limits to what can be done.
“It can never return to its previous state in our lifetime,” Watson said. “He has sadly changed forever.”
The Mililani Mauka Fire – named for the area near where the fire started – burned in the Koolau Mountains. These mountains are on the wetter, windward side of Oahu because they trap moisture and rain that crosses the island from the northeast.
But repeated and more prolonged drought events dry out even the Koolaus. Gon expects more frequent fires in Koolau in the future.
“There has been a huge increase over the last 10 years, mainly in the Waianae Range, which is the western and driest part of the island,” Gon said. “But now we are seeing fires in the humid part of the island which normally does not see any fires.”
Fires in Hawaii are almost always started by humans. Gon therefore said that more needs to be done to raise awareness about prevention. Native forests could be further protected with buffer zones by planting less flammable vegetation on former sugarcane and pineapple plantation lands, often located at lower elevations, he said.
Many of these now fallow fields are growing dry, invasive grasses. These weeds fueled the fire that ravaged Lahaina in August, highlighting their dangers. The cause of the fire is still under investigation, but it may have been started by downed power lines that ignited dry grass. Winds linked to a powerful hurricane passing to the south helped spread the fire, which destroyed more than 2,000 buildings and homes for some 8,000 people.
The fire is likely to affect Oahu’s fresh water supply, although this is difficult to measure. Oahu’s million residents and visitors get their drinking water from aquifers, but it usually takes decades before rain seeps into the ground to recharge them. Native forests are the best at absorbing rain, so the loss of high-quality forests will certainly have some effect, Watson said.
State officials are seeking additional funds from the Legislature next year to update firefighting equipment, fire breaks, new water sources for fire suppression, replanting of native trees and plants and seed storage.
Firefighters and rain last week finally dampened the Oahu fire, but Gon urged action now “to ensure it doesn’t turn into annual fires eating away at the source of our water supply.” .