Frequently Asked Questions

All What is ROD & how can I spot suspect trees? Where is ROD & where did it come from? How does ROD move? What is being done about ROD? What can I do to help? What if I have infected trees on my property? Can I buy or sell ʻōhiʻa for firewood? Tips for bulldozing My land has ROD, should I bother planting ʻŌhiʻa? Can I use ROD-infected ʻōhiʻa wood at all?

What is Rapid 'Ohi'a Death?

Rapid ʻŌhiʻa Death is a disease caused by two fungal pathogens. Ceratocystis lukuohia (destroyer of ʻōhiʻa) is the name of the more agressive fungus and Ceratocystis huliohia (disruptor of ʻōhiʻa) is the less agreessive fungus. Both of these fungal pathogens kill ʻōhiʻa, Hawaiʻi’s most abundant native tree.

How exactly does ROD kill ʻōhiʻa?

The fungus enters the tree through a wound. A wound can be caused in many ways and might not be visible. Humans can wound trees by running over roots with a lawnmower, cutting through bark with a weedwhacker, pruning, cutting into trees to mark trails, hiking over exposed roots, etc. Strong winds, broken branches, included bark, and roots growing over lava rock can also cause wounds large enough to allow infection. Once the fungus enters the tree it grows into the vascular system (sapwood) and stops water from moving up to the crown of the tree.

How can I identify an ʻōhiʻa tree that might have ROD?

The ROD-causing fungi are not visible on the outside of the tree, so a few characters may help determine if your tree might be infected. First, an apparently healthy tree's crown will turn from green to yellow then brown and appear dead over a few days to weeks if it has ROD. Next, leaf death will not be scattered but entire branches or the entire crown will die at once. If the tree is in a location were ROD is rare or unconfirmed, then it is possible that the tree died from something other than ROD such as injury or other pathogens. There are several diseases that kill ʻōhiʻa trees and show symptoms similar to ROD. If the tree is in a location where ROD is already prevalent, then it’s very likely that the tree has died from ROD infection. To be positive that the tree has ROD, a wood sample must be submitted for testing.

How quickly can the fungus kill an ʻōhiʻa tree?

When the fungus infects a tree, it may take a year or longer before the tree shows symptoms of the disease (i.e., before the tree actually looks like it’s dying). Once a tree shows symptoms it usually dies within a few weeks. It seems that the disease does not kill trees as quickly in colder and drier locations.

Is ROD found on all the Hawaiian Islands?

Not at this point, but more detections have been made especially in the past two years. The more aggressive ROD-causing fungus, Ceratocystis lukuohia, has been confirmed on Hawaiʻi Island and Kauaʻi. The less aggressive fungus, C. huliohia, has been confirmed on Hawaiʻi Island, Kauaʻi, Maui, and Oʻahu.

Where does the fungus that causes ROD come from?

The exact origins of the ROD-causing fungi are unknown, but we know that they are not native to Hawaiʻi. ROD is an exotic/introduced disease. There are several hypotheses for how these fungi originated: 1) a strain was brought in on a plant carrier that wasn’t showing symptoms of the disease, 2) a different strain was brought to Hawaiʻi and mutated or 3) two separate strains were brought to Hawaiʻi and recombined to create the strains that are killing ʻōhiʻa.

Do I need to worry about ROD affecting me or my other plants in the yard?

The fungal species that cause Rapid ʻŌhiʻa Death are specific to plants – humans will not be affected.

So far, the ROD-causing fungi are specific to ʻōhiʻa –you do not have to worry about ROD infecting other plants.

Can humans move the fungus?

The fungi live in the sapwood of infected ʻōhiʻa trees and the spores can live for a year or more after the tree is cut. Moving wood such as firewood or posts from infected trees will move the fungal pathogens. In addition, humans can move fungi on clothing, shoes, gear (such as backpacks), and equipment (such as saws, machetes, and machinery). Beetles boring into infected trees create a fine boring dust mixed with infectious fungal spores that can settle to the ground and mix into the soil under ʻōhiʻa trees. If off-road vehicles drive through infected stands they can pick up mud from under the trees and transport the fungus to new locations.

Can I take ʻōhiʻa to another island?

No, not without a permit. The Hawaiʻi Department of Agriculture has declared a quarantine rule that prohibits interisland movement of all ʻōhiʻa plant or plant parts from Hawaiʻi Island including:

Logs, wood, leaves, twigs, flowers, seeds, stems, cuttings, soil
Untreated wood, green waste, mulch, sawdust, wood chips and frass (wood dust from boring beetles)

For more information on Hawaiʻi Department of Agriculture rules and recommendations see: http://hdoa.hawaii.gov/blog/main/reportingohiawilt

What is the role of beetles in spreading the disease?

Several types of beetles, including ambrosia beetles and long-horned beetles, bore into infected trees and create a fine dust called frass. This beetle-made frass is contaminated by fungal spores and can be blown on the wind, spreading the disease. So far, studies have found that around 10% of beetles test positive for the ROD fungus, yet there is no evidence that beetles themselves cause ROD disease in healthy trees.

Can the fungus or the spores of the fungus be carried in the wind?

The fungus grows inside the sapwood of infected trees and not on the bark or leaves. The fungal spores themselves are not windborne. However, beetles boring into infected trees create a fine dust that is contaminated by fungal spores and can be blown on the wind, spreading the disease.

What research is being conducted to improve understanding of ROD?

Scientists, researchers and land managers are working together to understand various aspects of this new disease.

Some of the current research includes:

Mapping the distribution of ROD
Using remote sensing techniques to discover locations of stressed trees that may be infected with the ROD fungus
Using computer modeling and geographic information systems to examine landscape or ecological patterns of the disease
Monitoring long-term forest plots to learn how the disease progresses over time in a given location
DNA test improvement to increase ability to test for ROD in the field and lab
DNA testing on beetle and beetle-made wood dust ("frass")
Wood dust ("frass") trapping to see how much is being carried by wind
Testing fungicides for effectiveness against Ceratocystis
Testing different varieties of ʻōhiʻa to search for resistance to ROD
Testing best methods for preventing the spread of ROD
Testing methods for treating wood products so that they do not carry spores of the ROD fungi

Is there a cure for ROD?

There is currently no cure for trees that have already become infected with Rapid ʻŌhiʻa Death. Avoiding injuries to ʻōhiʻa is the best way to prevent disease from occurring. Keep lawnmowers, weed trimmers, and pruning saws away from ʻōhiʻa trees. Step over or around ʻōhiʻa roots while hiking.

Don't track disease-causing organisms around. Brush all soil and debris off of shoes, gear, and tools and then spray with 70% isopropyl (rubbing) alcohol. When spraying, coat shoe soles and allow the solution to sit for 15 seconds before hitting the trail.

Are there any treatments that can kill the fungi that cause ROD?

There are currently no recommended fungicides (fungus-suppressing chemicals) for treating Rapid ʻŌhiʻa Death. Researchers are experimenting with different chemicals, however a successful chemical would only be used in a greenhouse setting or on individual trees. Using a fungicide would likely be expensive because the chemical would require repeat applications. A successful fungicide would also not be able to cure a tree that is already infected, but it may be able to slow the fungal growth and prolong the life of the tree.

What can I do to help prevent the spread of ROD?

Practice the “5 things you can do to help prevent the spread of ROD.”

Avoid injuring ʻōhiʻa. Wounds serve as entry points for the fungus and increase the odds that the tree will become infected and die from ROD. Avoid pruning and contact with heavy equipment wherever possible. Stay off of ʻōhiʻa roots while walking or hiking.
Don’t move ʻōhiʻa wood or ʻōhiʻa parts. If you don’t know where the ʻōhiʻa material is from, don’t move it.
Don’t transport ʻōhiʻa inter-island. Follow the Hawaiʻi State Department of Agriculture quarantine rule and help to keep ROD from reaching the other islands.
Clean your gear/tools. If you must work around or cut ʻōhiʻa, clean tools and gear before and after use, especially when used on infected ʻōhiʻa. Brush all soil off of tools and gear, then spray with 70% rubbing alcohol. Shoes and clothes should also be cleaned before and after entering forests. Wash clothes with hot water and soap.
Wash the tires and undercarriage of your vehicle with a high pressure water source and remove all soil or mud, especially after traveling from an area with ROD and/or if you have traveled off-road.

If you’d like to do more, go to the homepage and click on the “How to Help” tab at the top.

If I need help cutting down my dead, ROD-infested ʻōhiʻa tree(s), whom do I call?

We recommend that you call an arborist who has been certified by the International Society of Arboriculture (ISA). Talk with the arborist about his/her current decontamination procedure as well as practices we recommend to prevent the spread of ROD. The Big Island Invasive Species Committee (BIISC) has a list of Certified Arborists for Hawaiʻi Island.

The ROD-infected ʻōhiʻa tree has been cut down – now what do I do?

If you are fairly certain that the tree is infected and dead, then we recommend that you have the tree cut down safely. We recommend felling the tree on a still day to minimize blown sawdust and using a sharp saw to create chips rather than dust. You may use the wood as fuel for an imu, fireplace, smokehouse or barbecue on site but you may not dispose of it in an open brush fire unless you get a burn permit from the Department of Health. You can also cut the tree up and cover it with a tarp, cloth or weed mat to contain any dust or frass created by boring beetles. The fungus can live in the wood for at least four years.

Is there anything I can do to save ʻōhiʻa on my property?

Because the ROD fungus enters trees through wounds, the best thing you can do to protect your trees is prevent them from getting injured. Mechanisms of injury include: lawnmowing, weedwhacking, cutting, sawing, pruning, etc. If you have grass that grows up to the edge of your tree, pull the grass back or put down a mulch or solid barrier (such as plastic or rocks) around the base of the tree, about 6 inches away from the trunk, so that grass-trimming equipment will not accidentally injure the tree. If a tree does get an injury, use plant sealant (or latex house paint) to seal the wound. It creates a barrier to prevent fungal spores fro mgrowing in the sapwood.

Also, avoid stepping on ʻōhiʻa roots. Injured roots are also a way for the fungal pathogen to enter the plant.

What can I do to help spread awareness about ROD?

There are many ways to help spread awareness about ROD. Start to educate your family and friends about the threat of ROD and share and practice the 5 things everyone can do to prevent the spread of ROD. Invite a ROD researcher to give a talk in your community and help to organize the event. Request a ROD informational booth at a community event and volunteer at the booth (contact UH educational specialist, Corie Yanger for Hawaiʻi Island or the ROD Statewide Outreach Coordinator, Ambyr Mokiao-Lee for other islands). Print or request ROD brochures, stickers, handouts to share in your community.

How can I help if I don't have ʻōhiʻa on my property?

Even if you don't have ʻōhiʻa on your property, you may come into contact with ʻōhiʻa. Think about whether you use forest products (for example, wood or lei materials), hike or hunt. If you participate in these activities, it is highly important to share and practice the 5 measures for preventing the spread of Rapid ʻŌhiʻa Death. ʻŌhiʻa are the foundation of our forested watersheds in Hawaiʻi and are responsible for replenishing our fresh water supply. Educate friends and family on the importance of this issue and help to prevent spreading ROD.

Can I use ʻōhiʻa for firewood?

Yes, ʻōhiʻa can be burned safely in a fireplace, barbecue, imu, or smokehouse but take precautions to prevent spreading Rapid ʻŌhiʻa Death. Burn ʻōhiʻa firewood obtained from your property or from your neighborhood. ROD-causing fungus will not survive heat from a fire, will not get carried in the ashes, and will not be a threat to humans as the fungus is specific to plants.

If you have to move ʻōhiʻa wood, keep it contained in a box or another enclosed vessel. At the very least, cover the wood with a tarp to keep wood particles from flying around.

If wood is cut to firewood size before it's moved, there will be less chance of moving the disease than if they are moved and then cut. Buyers should be particularly aware of the risk of spreading ROD by cutting at a new location, especially areas of mostly healthy ʻōhiʻa forest. When cutting ʻōhiʻa, use as few saw cuts as possible to reduce the amount of fine particles. Once wood is bucked up, use an axe to cut wood into suitable firewood pieces.

Alternatives to ʻōhiʻa firewood include kiawe (Prosopis pallida) and macnut (Macadamia integrifolia). REMEMBER: always check firewood to for diseases and pests, like ROD or fire ants, before you move it.

Can I sell ʻōhiʻa for firewood?

Yes, ʻōhiʻa can be sold legally for firewood; however, please handle the wood and advertising responsibly to avoid spreading Rapid ʻŌhiʻa Death (ROD) disease.

Within the Island of Hawaiʻi there are no legal restrictions to moving or selling ʻōhiʻa. The Hawaiʻi Department of Agriculture quarantine restricts shipping of ʻōhiʻa off Hawaiʻi Island, which means any piece of ʻōhiʻa (log, posts, foliage, etc.) has to be tested free of ROD disease before moving off the island.

We highly recommend that people not move ʻōhiʻa firewood or posts because moving infected wood can indeed spread ROD. The best practice for firewood is to not move ʻōhiʻa wood out of your neighborhood.

If you sell ʻōhiʻa wood, be transparent in your advertising. If you aren't certain of the presence of ROD, say so as a disclaimer. Let buyers or potential buyers know that the current recommendation is to keep ʻōhiʻa wood in your neighborhood.

When cuting ʻōhiʻa, keep saw cuts to a minimum to avoid creating a lot of fine particles. Once wood is bucked up, use an axe to cut the wood into pieces suitable for firewood. If the wood will be cut up at another location, the buyer should be aware of the risk of spreading ROD by cutting at the new location, especially areas of mostly healthy ʻōhiʻa forest.

How can I help to prevent the spread of ROD if I am a hiker or camper?

The fungus that causes ROD can infect trees through injuries or breaks in the tree’s bark. Campers and hikers can prevent the spread of ROD by sanitizing gear, taking care to not injure ʻōhiʻa trees while hiking, and not moving ʻōhiʻa firewood.

Always clean your shoes and gear before and after entering forests. 1. Use a brush to scrap off all dirt and seeds. 2. Spray to coat the bottoms of your shoes with 70% isopropyl (rubbing) alcohol -do the same to hiking poles if you use them.
Many hiking trails through native forest will have ʻōhiʻa roots exposed on the path. To avoid injuring ʻōhiʻa, don’t step on or crush roots.
Don’t mark trails by “blazing” or cutting into trees with a hatchet or machete. Mark trees with paper or flagging if necessary.
Collect or purchase locally-sourced firewood and always inspect it for pests, especially little fire ants, before moving it to another location.
Transport cut wood in a container or at least under a tarp to avoid wood chips or sawdust blowing around.
Burning ROD-infected ʻōhiʻa will kill the disease-causing fungus.

How can I help to prevent the spread of ROD if I am a logger or miller?

Loggers and millers can help to prevent the spread of ROD by incorporating best practices for handling ʻōhiʻa into the processes for cutting trees, transporting wood, and sanitizing equipment.

When cutting ʻōhiʻa avoid injuring nearby ʻōhiʻa trees, especially if those trees appear healthy and are not intended for harvest. Any break in the bark can allow ROD-causing fungus to enter and cause infection in the trees.
Sawdust can be full of fungal spores. Minimize the amount of sawdust by keeping chainsaws sharp.
If possible avoid harvesting on dry, windy days when sawdust can blow for miles.
Transport logs in a container or covered with a tarp, if possible, to reduce sawdust or wood chips blowing around.
Cut firewood to size on the logging site rather than transporting whole logs and cutting them up and spreading potentially infected sawdust elsewhere.

Prevent the spread of ROD disease by sanitizing equipment and vehicles before and after use.
Clean saws and other tree-cutting tools between sites. Remove wood particles and debris before coating tools with 70% rubbing alcohol spray and allow to sit for 15 seconds before using the tools again.
Wash vehicles with a pressure washer or other high pressure water source to remove all mud and debris, especially from the undercarriage, wheel wells, and tires. Vacuum vehicle interiors where practical. Be careful with ATVs, as pressure washing can damage seals and bearings.

Testing or treating by an approved method is required by law for any ʻōhiʻa wood or post to be shipped off of Hawaiʻi Island. Permitting and testing for off-island shipping is conducted by the Hawaiʻi State Department of Agriculture. ʻŌhiʻa trees can live for months while infected with the fungus that causes ROD, and many trees that did not show symptoms have tested positive. The only way to know if an ʻōhiʻa is infected with Rapid ʻŌhiʻa Death is to test a wood sample.

The fungus that causes ROD will die when wood is heated to over 140 degrees F or dried to less than 15% moisture content. Any ʻōhiʻa lumber or flooring can be used safely after it has been dried in a lumber kiln. Heat treating has been shown to kill the ROD causing fungus in small posts, but there is currently no treatment to kill the fungus in larger posts and the Hawaii Department of Agriculture is still developing approved methods for treating posts.

How can I reduce bulldozer impacts on ʻōhiʻa at my property?

The fungus that causes Rapid ʻŌhiʻa Death enters trees through wounds. If you need to work with a bulldozer to clear land, there are steps you can take to minimize injuries to ʻōhiʻa trees.

Where possible, choose to work with a bulldozer operator located in your neighborhood or area. Look for someone who operates a small, low-impact machine.

Ask the operator to bring a clean machine to your property or work site to prevent spreading ROD.

Hand clear the path for the bulldozer ahead of time. Trees can be hand-cleared and tree ferns can be transplanted. Use a gravel layer on top of soil to minimize the need for removing soil. Try to place the driveway path where valuable trees are less dense and make the path only as wide as you need to fit your vehicle. Ask the bulldozer operator to give ʻōhiʻa a wide buffer to minimize damage to roots and trunks.

Fresh injuries to ʻōhiʻa can be sprayed with a pruning sealant to prevent ROD-causing fungi from landing on the wounds and causing infection. Be aware that the use of pruning sealant will not guarantee that the tree will be safe from infection.

My land has/had ROD, should I bother planting ʻōhiʻa on my property?

Yes! Research shows that keiki ʻōhiʻa planted in areas with active ROD can survive long enough to become reproductive (flowering), especially if weeds are kept away and trees are kept safe from wounds from things such as pigs or weedwhackers. Keep planting ʻōhiʻa!

Partners

University of Hawaiʻi at Mānoa College of Tropical Agriculture and Human Resources | USDA ARS Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center | USDA Forest Service Institute of Pacific Islands Forestry | Department of Land and Natural Resources, Division of Forestry and Wildlife | University of Hawaiʻi at Hilo | The Nature Conservancy (TNC) | Hawaiʻi Association of Watershed Partnerships | Coordinating Group on Alien Pest Species (CGAPS) | Big Island, Maui, Moloka ʻ i, O ʻ ahu, and Kaua ʻ i Invasive Species Committees (ISCS) | USFS Region 5 State and Private Forestry | USGS Pacific Island Ecosystems Research Center | Global Airborne Observatory | Hawaiʻi Invasive Species Council | Hawaii Department of Agriculture -Plant Quarantine Branch | Hawaiʻi Volcanoes National Park | Hawaiʻi Tourism Authority |Hawaiʻi Island Seed Bank | Maui Nui Botanical Gardens | National Tropical Botanical Garden | Lyon Arboretum | Laukahi Hawaiʻi Plant Conservation Network