A quarantine to prohibit the movement of ohia trees, the soil surrounding them and ohia products from the Big Island is is likely to be approved this month in an attempt to stop the spread of a fungus that has the potential to kill the native trees throughout the islands.
Day by day the disease spreads, killing off hundreds of mature ohia trees on more than 15,000 acres in the forests and residential areas of Puna and Hilo, according to the state Department of Agriculture.
“It is devastating to our native forests,” says Lisa Keith, a research plant pathologist with the USDA Agriculture Research Service in Hilo.
“I have never seen anything move this fast and kill this many trees in Hawaii,” says J.B. Friday, an extension forester for the University of Hawaii.
The infestation was first reported by Environment Hawaii in June.
The fungus is currently found only on Hawaii Island, but it has the potential to spread to the other islands.
State Agriculture Board Chairman Scott Enright says it is unusual to move quickly to quarantine a plant, but “because this ohia fungus is such a threat to the forests, we are being extremely pro-active.”
At the Board of Agriculture meeting Aug. 25, the panel is expected to approve the quarantine. Enright says it will be in effect until procedures can be found to test ohia trees and their products to be certain they are free of the fungus.
“Without the quarantine, we will be playing Russian roulette with forests on the other islands.” — Flint Hughes, Forest Service plant ecologist
Enright says this disease is particularly troubling because it is still unknown if the fungus killing the ohia trees can be spread throughout the islands on other plants.
Flint Hughes, a plant ecologist with the USDA Forest Service, says the quarantine will be a big help to stop the fungus from spreading from the Big Island.
“Without the quarantine, we will be playing Russian roulette with forests on the other islands,” says Hughes.
The fungus attacking the ohia is called ceratocystis fimbriata, also known as ohia wilt or rapid ohia death.
Researchers are still trying to determine its particular strain and how it arrived on Hawaii Island and how it spreads.
“There are lots of reasons ohia trees die, but this is something new and alarming,” says Friday.
Friday was alerted to the dying ohia trees by a landowner in lower Puna in 2010. He subsequently responded to reports of dying trees in the Leilani Subdivision in South Pahoa in 2011.
But it was not until 2014 that plant pathologist Keith nailed down the type of fungus. “We are continuing DNA studies to try to pinpoint its origin,” says Keith.
At the beginning of this month, Young Brothers jumped ahead of the stateʻs quarantine efforts by instituting its own ban on the shipment of ohia products.
Young Brothers will not transport ohia plants and products between the islands until the Agriculture Department develops an inspection process to be sure ohia products are disease free.
“As the largest inter-island water carrier in Hawaii, it is important to be proactive,” says Roy Catalani, Young Brothers vice-president for external affairs. “We want to do what we can to stop the spread of ohia wilt.”
Hawaiiʻs watershed is dependent on native ohia forests. The trees make up more than 50 percent of native forest canopy.
When ohia trees die, non-native species can invade, creating conditions that kill endangered native plants, birds and insects.
The ohia tree is also important to Native Hawaiian culture. When volcanoes erupt, the ohia is one of the first forms of life to emerge from the cooled lava.
Ohia flowers are considered sacred to Pele, goddess of volcanoes, and Pele’s favorite flower.
Kumu hula Manu Boyd says, “Ohia lehua is a kinolau , a physical manifestation of our deities, particularly Laka, the goddess of hula.”
Boyd calls the rapid death of ohia trees “devestatating because ohia is useful in so many ways both for building houses, making hula adornments, and for the beauty of ohia lehua flowers in their many colors, and the tree’s enduring symbolic power to the people of Hawaii.”
Sam Gon, a respected Hawaiian chanter, says ohia is also the physical manifestation of Kukailimoku, the war god who was the patron of Kamahameha I.
Gon says when an ohia tree was cut down to make an image of Ku, the required sacrifice was a human.
He calls the ohia deaths “very troubling. We must do everything we can to isolate the disease and work with other conservation groups to find a solution.”
Besides being a chanter, Gon is the senior scientist and cultural advisor to the Nature Conservancy of Hawaii.
Plant pathologist Keith says this new ohia disease is much more serious than the so-called ohia die-off that affected some trees in the 1980s.
It is still unknown if insects transmit the disease or whether insects attack already-infected trees.
Once the fungus gets inside a tree, it quickly kills the organism by shutting down its vascular system, halting the transportation of water and nutrients that nourish the tree.
The leaves of affected trees turn yellow, then brown. Then, within days to weeks, the tree dies.
Death comes so quickly that the leaves are still on the tree when it expires.
The fungus also causes dark, nearly black stains in the sapwood along the outer margins of the trunk.
Keith says the fungus is similar to the black rot found in sweet potatoes in Hawaii in the 1940s, but it is not exactly the same.
The pathogen can remain viable for over a year in the dead wood of an ohia tree.
Traces of the ohia fungus can also be found in the soil around infected trees, making it easier for people to spread the disease when they walk around the tree.
Friday says the most important thing people can do to prevent the spread of the fungus is to refrain from moving ohia plants and their soil to other areas.
He says people working with tools around ohias should clean everything carefully and to wash their muddy trucks and carefully clean their boots and their clothing.