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Rid of ROD

By Office of Communication Services    Published on 11/01/2016 More stories >>

Community members, natural resource managers, and scientists are working together to combat ROD.

Community members, natural resource managers, and scientists are working together to combat ROD.

Extension forester J.B. Friday speaks for the trees. Right now, it’s the ‘ōhi‘a (Metrosideros polymorpha) that need his advocacy, due to a devastating new disease that’s decimating forests on the Big Island. Rapid ‘ōhi‘a death (ROD) is estimated to have killed mil-lions of trees over 50,000 acres in the Puna, Hilo, Kā‘ū, and Kona districts. These iconic trees make up 80% of the native canopy of forests in the Islands and are an essential part of a complex system of other plants, insects, and birds, including native and endangered species.

The disease is dramatic. Affected trees die within weeks or even days once they start showing symptoms. Crowns turn yellowish and then brown, while infected wood is streaked with black and, interestingly, smells like bananas. The fungus causing the disease, Ceratocystis fimbriata, is a well-known pathogen worldwide, and other strains have infect-ed sweet potato and taro in Hawai‘i for decades, but the strain causing ROD is unique.

Along with fellow members of the “ROD Squad” Dr. Flint Hughes of the USDA Forest Service and Dr. Lisa Keith of the USDA ARS, Dr. Friday is working to increase knowledge about, funding for, and awareness of ROD. The three were honored by the Hawai‘i Invasive Species Council for their work against the disease. Dr. Friday also worked to pass House Bill 1597, which funded the Hawai‘i Department of Agriculture to address it, and lent his expertise to a crowdfunding campaign from UH’s Lyon Arboretum that raised more than $50,000 to collect and bank seeds from different varieties of ‘ōhi‘a—they can be endemic to a single island—for testing for resistance to ROD and future reforestation efforts.

Dr. Friday shows characteristic signs of disease on a native ‘ohi‘a.

Dr. Friday shows characteristic signs of disease on a native ‘ōhi‘a.

Researchers are still learning about what’s spreading the disease. A possible vector could be beetles that bore into infected trees and create spore-bearing sawdust, which can blow into nearby uninfected stands. Dr. Gordon Bennett and Dr. Curtis Ewing of CTAHR’s Department of Plant and Soil Sciences are setting traps for the beetles to look for fungal contamination and testing wind currents for infected sawdust to see if the disease is moving this way.

ROD could also be easily spread by people moving infected wood for firewood or posts. For that reason Dr. Friday emphasizes that the most important way to help contain it is not to move any ‘ōhi‘a materials or soil around the trees, and he was instrumental in supporting a new HDOA quarantine restricting movement of ‘ōhi‘a off the Big Island. Some good news is that the disease hasn’t been reported on any of the other islands or in the Hāmākua or Kohala districts.

More good news is the outpouring of concern and support from a wide range of individuals and institutions concerning the disease. “ROD is one environmental issue where everyone is on the same side,” says Dr. Friday. “We have had amazing collaboration and support from federal and state agencies, non-profits and foundations, elected officials, Hawaiian cultural practitioners, and community members. No one wants to lose the ‘ōhi‘a forest.”

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