There’s no cure for rapid ohia death, but researchers working to contain the threat are hoping more public outreach will help manage the deadly tree disease.
A symposium presenting the latest research updates took place Saturday at University of Hawaii at Hilo, drawing about 40 people, many of whom came with notebooks in tow to take down the wealth of information presented throughout three hours.
A second symposium is slated for April 1 in Kailua-Kona at the West Hawaii Civic Center Council Chambers.
Rapid ohia death is caused by a fungus called Ceratocystis. The fungus blocks a tree’s vascular system so it cannot get nutrients. A tree can be infected long before symptoms appear, but once they do (in the form of browning leaves) the tree dies within a short period of time.
Since Ceratocystis was first identified as the cause of ROD, the disease has been found around the island. Kohala has not yet been affected, but last November a tree in Laupahoehoe was discovered with the disease. There have been a few other cases found in Hamakua since.
ROD has not been found on any other islands, and there is a permanent quarantine on shipping ohia off the Big Island.
The rapid ohia death working group includes more than 200 people throughout the state. Eight scientists and researchers provided updates on their work during Saturday’s talk.
“Everyone’s driven by a real sense of desperation to come up with answers as quickly as possible, and to try to gain understanding to help save our trees,” said Flint Hughes of the U.S. Forest Service. Hughes and UH-Hilo professor Ryan Perroy discussed the ongoing aerial surveys that are used to track the spread of the disease, as well as mortality rate within particular stands of ohia.
Hughes said that between 2015 and 2016, more than 200,000 and possibly as many as 300,000 ohia died.
If the tree were to be utterly lost, he said, “We’d be left with much smaller forests, shrubby forests, many of which would be dominated by non-native species like strawberry guava. In some places we’d have tree fern forests, but that’d be the best case scenario.”
An ohia forest that has younger and smaller trees tends to show lower mortality rate than forests with large mature trees, but researchers are not yet sure exactly why.
Lisa Keith of the U.S. Pacific Basin Agricultural Research Center said her lab is working on several projects, including determining whether certain varieties of ohia are more resistant than others.
“Even in the most devastating pictures that you’re seeing today, some trees are surviving,” Keith said. “Lots of areas still have trees that do not come down with infection, so I think that the genetic variability of ohia is working in its favor.”
There also is genetic variability within the Ceratocystis fungus that causes ROD. Keith’s lab discovered two separate species that so far have been found nowhere else in the world. They have not yet been formally named, and are being referred to as Species A and Species B.
Distribution of the two species varies; Species B is more common in North Kona, for example.
Curtis Ewing, a junior researcher in the UH College of Tropical Agriculture and Human Resources, has studied how the fungus is spread, focusing his work on boring beetles that release frass as they burrow into a tree. If the tree is infected with ROD, the frass will contain fungal spores that can then get blown around the island by wind.
The beetles’ burrowing creates wounds in the ohia trees, which researchers found is strongly associated with infection rates. Trees also can be wounded by climbing spikes, weed whacking at their base, foraging livestock or heavy wind activity (as with Hurricane/Tropical Storm Iselle).
“Usually, the same type of activity that release infectious material also creates a pathway to infection in a healthy tree,” Ewing said.
County Council members Eileen O’Hara and Jen Ruggles participated in the symposium. O’Hara and Ruggles represent Puna, which has been hit hardest by rapid ohia death. The first cases were discovered in Leilani Estates beginning in about 2010.
Ruggles said one of the biggest problems the working group faces is a need for more education among arborists and others “on the ground working with these trees every day.”
The group is working to set up training with International Society of Arboriculture-certified arborists on the island, CTAHR extension forester J.B. Friday said, but “only about 10 percent of the people who are doing this (tree removal) are certified.”
“You don’t need much certification to go cut trees,” he said.
O’Hara pointed out that many people don’t hire arborists at all, choosing to cut trees on their own.
“It’s not just arborists,” she said. “It’s contractors who are clearing land and moving soil, so everybody across all the industries needs to be educated and needs to be observing best practices.”
Mayor Harry Kim’s recent proposed budget would create a county arborist position, a role first proposed during former Mayor Billy Kenoi’s administration. Hawaii County is the only county in the state without such a position, Friday said.
Funding for ROD management, research and outreach remains a concern.
Most funding to date is “soft funding,” Friday said, meaning it is from grants. These grants have come from private, federal, state and county sources.
“If we lose all of our funding, you’re back to me, Lisa and Flint doing this job in addition to our normal work,” Friday said.
Four bills were introduced in the state Legislature this year to provide appropriations for ROD, but only one is still alive (a bill that would have named ohia the state tree did not receive any hearings at all).
Senate Bill 1239 crossed over to the House of Representatives and was heard Thursday by the committees on Energy and Environmental Protection and Agriculture. It passed both and was referred to the Finance Committee.
A dollar amount has not yet been specified in SB 1239. But one of the bills that died would have appropriated about $3.6 million for implementation of the Rapid Ohia Death Strategic Response Plan, which was launched last year.
The three-year plan asks for just more than $10 million in funding within that time frame. The $3.6 million would have been the start.
In the big picture, O’Hara said, that funding amount wasn’t so much to ask for.
“What they’ve done already with the funds they had is amazing,” she said.
Some in the audience were concerned that federal funding sources would dry up in light of President Donald Trump’s administration’s call to cut back departments such as the Environmental Protection Agency.
The U.S. Forest Service is a division of the U.S. Department of Agriculture. Trump’s recent discretionary spending proposal also called for cuts to that agency, as well as to the Department of the Interior, which last year provided $497,000 in federal funds to create an ROD Early Detection Rapid Response team.
Final discretionary spending appropriations will be voted on by Congress.
“We’ve had very good support from Hawaii’s Congressional delegation, but they are the minority party,” Hughes said.
Email Ivy Ashe at iashe@hawaiitribune-herald.com.
What you can do to help
• Don’t move ohia. There is a quarantine on transporting ohia in any form (wood, leaves, flowers, mulch) from the Big Island, but transport within the island remains a concern.
• Don’t wound ohia trees. The Ceratocystis fungus cannot enter and infect an ohia tree without an opening. Climbing spikes used by arborists create wounds. Livestock, particularly cows, also can inflict heavy damage on tree bark.
• Practice good forest hygiene. Clean mud off boots and gear and keep vehicles clean.
• Decontaminate cutting tools. Rubbing alcohol is the best disinfectant because it is easily accessible, inexpensive and effective.
• Spread the word about rapid ohia death and best practices. Visit www.rapidohiadeath.org for more information.