Rapid ʻŌhiʻa Death
Rapid ʻŌhiʻa Death
Rapid ʻōhiʻa death is a fungal disease that is taking Hawaiʻi by storm. It attacks the ʻōhiʻa tree, an important species in Hawaiian forests and culture.
ʻŌhiʻa is a food source for lots of Hawaiian wildlife. Several species of birds feed on the nectar of the ʻōhiʻa tree, including an endangered species, the Hawaiʻi Akepa.
Because ʻōhiʻa is so common in Hawaiian forests, it is considered a very important species around rivers and streams. Healthy forests help filter water and prevent the soil from being washed away. Without ʻōhiʻa, some of Hawaiʻi’s streams and rivers could be at risk.
ʻŌhiʻa is one of the most common plants of the Hawaiian Islands. Some forests are 80% ʻōhiʻa! Losing such a common species would harm the forests of Hawaiʻi.
The inside of this tree is stained black from the rapid ʻōhiʻa death fungus. It blocks the cells in the tree that transport water so the tree cannot drink!
To test for rapid ʻōhiʻa death, researchers will take samples of diseased portions of a tree to a lab and culture them. Culturing is when fungus or bacteria are grown intentionally, like in the petri dish pictured here.
Once rapid ʻōhiʻa death has infected a tree, it will quickly begin to show signs of the disease. This fast moving fungus causes leaves and whole branches to die back. If you see an ʻōhiʻa tree with lots of dead yellow or brown leaves, it may be infected.
ʻŌhiʻa lehua is an important plant in the traditional culture of Hawaiʻi.
A traditional Hawaiian building or house is called a ‘hale’. ʻŌhiʻa was sometimes used for the beams and poles that support the hale—if they were straight enough!
ʻŌhiʻa is used medicinally by native Hawaiians. The bark and flowers can be mixed together and given to women during childbirth. The leaves are also used to stimulate appetite and to treat sore throats.
Until very recently, ʻŌhiʻa lehua flowers were used in lei and as part of traditional hula ceremonies. The Hawaiian people have stopped using them in some events because of the risk of spreading rapid ʻōhiʻa death.
ʻŌhiʻa wood was traditionally used in boat building.
Rapid ʻōhiʻa death kills quickly! Once a tree is infected, it can be killed in only a matter or weeks.
To date, rapid ʻōhiʻa death has been detected on Hawai‘i Island, Kauaʻi, Maui and Oahʻu. Some forests have lost 90% of their ʻōhiʻa trees in only 2-3 years.
Moving plants around is a big problem! The Animal and Plant Health Inspection Service (part of the US Department of Agriculture) is on the look out for invasive plants and pests like rapid ʻōhiʻa death.
Any tools used to cut or prune ʻōhiʻa should also be cleaned. This can be done with 70% rubbing alcohol.
To slow the spread of rapid ʻōhiʻa death the following things cannot be taken off Hawaiʻi island:
1) ʻŌhiʻa plants,
2) ʻŌhiʻa plant parts including flowers, leaves, seeds, stems, twigs, cuttings, untreated wood, logs, mulch, green waste, or any insect waste,
The University of Hawaiʻi and the U.S. Forest Service have set up these boot brush stations so hikers can clean off their boots. Rapid ʻōhiʻa death can move around in the soil stuck on the bottom of your shoes!
ʻŌhiʻa firewood should not be moved around Hawaiʻi Island, or between islands.
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‘Ōhiʻa trees: Forest and Kim Starr, Starr Environmental, Bugwood.org; ‘Ōhiʻa lehua leaves and flowers: Forest and Kim Starr, Starr Environmental, Bugwood.org; Hawai'i Akepa: Dominic Sherony, Wikimedia Commons; Kauai Heiau Poliahu Wailua River: Joel Bradshaw, Wikimedia Commons; Wood staining: Dr. J.B. Friday, University of Hawai’i; Oak wilt culture: Joseph O'Brien, USDA Forest Service, Bugwood.org; Damaged trees: J. B. Friday, University of Hawai'i, Flickr.com; ʻŌhiʻa lehua flower: Joel, Flickr.com; Hale: University of Hawai’i — West Oahu, Flickr.com; ʻŌhiʻa lehua flowers: David Eickhoff, Wikimedia Commons; ʻŌhiʻa lehua flower lei: College of Tropical Agriculture at University of Hawai'i at Manoa; Bark: Wildlife of Hawai'i. Dead trees: Dr. J.B. Friday, University of Hawai’i; Inspectors: USDA, APHIS, USDA.gov; Pruning tools: Joseph O'Brien, USDA Forest Service, Bugwood.org; ʻŌhiʻa lehua in pots: Forest and Kim Starr, Starr Environmental, Bugwood.org; Boot station: Dr. J.B. Friday, University of Hawai’i; Firewood: Sarah Altendorf, Flickr.com.