MOLOA‘A — Rapid ohi‘a death has found its way to Moloa‘a Forest Reserve on Kauai.
State Department of Land and Natural Resources botanist Adam Williams discovered five trees that looked like they were dead from symptoms associated with ROD while working in the reserve earlier this week.
By Wednesday, a team of state and federal officials, and people from university and non-governmental organizations had hiked into the area and started collecting data, taking photos and making observations.
Turns out, test results show it’s the less aggressive of the two fungi that are known to cause ROD on Hawaii Island.
“What were are finding on Kauai is a very different pathogen from the fungus killing large numbers of ohi‘a tress on Hawaii Island,” said Lisa Keith, lead researcher from the U.S. Department of Agriculture’s Agricultural Research Service.
She continued: “That fungus, Ceratocystis lukuohia (formerly called Ceratocystis species A), is a harsh tree killer and is very aggressive.”
The fungus on the Moloa‘a Reserve ohi‘a is Ceratocystis huliohia (species B). It’s also widespread on Hawaii Island, and its impacts are much less severe and slower moving.
“Both of them kill trees,” Keith said. “(Ceratocystis huliohia) spreads more slowly, but it still kills.”
Both types of fungus grow in the sapwood of an infected ohi‘a tree and it usually gets into the tree through a wound from breaking branches or root trampling.
Once it’s in the tree, it can take two or three years for the tree to die, and it affects stands haphazardly. Some stands, though, have shown a 90 percent mortality rate from contracting species A of the pathogen.
Experts say the pathogen doesn’t affect the other plants in Kauai’s forests.
As experts and officials respond to the fungus on Kauai through data collection on the ground and via drone and helicopter observations, they hope to learn more and identify the extent of the infection.
Jeremy Campbell, woodworker in Kalaheo and member of the Hawaii Forest Industry Association, said it’s discouraging to hear the fungus has spread, but at least it doesn’t affect the whole forest.
“It’s unfortunate that it’s affecting a native species, but there’s not a lot of uses for ohi‘a,” Campbell said. “There might be some cultural uses.”
The hard wood is sometimes used for making posts and beams, Campbell explained, but isn’t in very high demand.
“What I want to know is how it got here,” Campbell said.
Kauai Invasive Species Committee manager, Tiffani Keanini pointed out a silver lining for Kauai, saying not as many Kauai homeowners have ohi‘a trees in their yards, so there will be less need for sampling and testing in residential areas.
“We do expect to be involved in continued work to investigate and test for the potential spread of the disease in the forest of Kauai,” she said.
The fungus can be transported through mud on hikers’ shoes, via dust in the air, and insect activity.
While data collection and investigation continues, everyone involved will be keeping a sharp eye to discover the extent of the fungus on Kauai.
“The initial discovery of ROD has certainly made all of our people who work in the forest more aware of what to look for,” she said. “Without that increased awareness, we may have not found it on Kauai and failed to take the steps we’re now taking.”
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Jessica Else, environment reporter, can be reached at 245-0452 or jelse@thegardenisland.com.
Please….do some deeper research on ROD. This is a very serious situation here on the Big Island, and to now have it on Kauai is no less serious. The tree has an extremely important role on both, or all islands as a base of the water shed on the slopes where it grows. Native Hawaiians also consider it a sacred tree. It is usually the first to grow back on lava flows and provides birds and bees a source of food. The comments that it is not a source of many uses is simplistic at the least.
I’d lay money on this being caused by the state importation of a parasite that kills guava. There is ample evidence that the state bureaucrats can barely see beyond their noses when it comes to unintended consequences associated with their actions/policies. Mongoose or Egrets anyone?
RG DeSoto
I agree with the previous post. It is actually a little bit sad to me to see this terrible event downplayed in our local newspaper because of its perceived lack of importance to humans. Having worked in conservation for 10 years on Kauai I can tell you that Ohia is of the utmost importance to our ecosystems. It is irreplaceable! Not only is it sacred to Hawaiians, Ohia covers 80-90% of our mountain slopes, provides nesting habitat and food for native birds, acts as a nursery tree for native shrubs and ferns and catches rainfall slowing it down so that it can replenish the aquifer. It literally is the native forest!! Not to mention it is a gorgeous stately tree with beautiful flowers. To upholds its relevance to humans, (as this is always important)- the recent flooding on Kauai would have likely been 10 times worse and in the future will be if our mountains lose the Ohia trees that hold their slopes together. It would be really nice if The Garden Island and the Hawaii media in general would begin a campaign to show the importance of this beautiful native tree so that awareness and appreciation grows and we can hopefully fight this devastating pathogen.
Mahalo
True, ohia wood does not have much commercial lumber value at the moment, but lets forget that it is important to the honey industry, a least on Hawaii island, and has a lot of biological value such as feeding the native honeycreepers, and is a dominant component of our watersheds, doing its part to capture fog drip in the higher elevations which allows more water to enter our streams and aquifers. In most windward areas which still have native forest canopy, it provides well over 80% of the existing canopy cover! As for how the pathogen could have gotten here: mud, chainsaws, dirtbikes, wood, machetes, boots, wind, etc. As the agencies test for it around the island, we’ll get a better picture of how far it has spread, how much of a problem it may be, and what to do next. Meanwhile, please don’t cut ohia (it needs a wound to enter), wash the mud off your shoes, clothes, vehicle, and equipment before going to a new area (basic sanitation). If you go to the Moloaa Forest Reserve, it is highly recommended (at the bare minimum) that you also spray the outside of your shoes with basic 70% isopropyl rubbing alcohol to sanitize.