‘Ōhi‘a Lehua Forests and ROD
‘Ōhi‘a trees are the bedrock of Hawaiian forests. Not only do they provide watershed protection and are a specific critical habitat for many biota, but they are also a critical food source for endemic birds (Friday and Herbert). ‘Ōhi‘a forests grow on the six largest Hawaiian islands: the Big Island, Maui, Moloka`i, Lana`i, Oahu, and Kaua`i. They are a resilient species, tolerant of various conditions such as frost, volcanic gases, and extreme changes in moisture (Friday and Herbert). “ ‘Ōhi‘a trees seed prolifically but grow slowly. They survive by colonizing lava flows or fallen logs in forest gaps where other vegetation cannot compete” (Friday and Herbert). This article explores endemic and endangered Hawaiian plants by examining the ‘Ōhi‘a lehua tree, and its history and importance in Hawaiian culture.
While there are different threats to ‘Ōhi‘a trees, this article focuses on ROD and its danger. Rapid ‘Ōhi‘a Death (ROD) is a fungal disease that quickly kills' Ōhi'a trees. Once a tree has been infected, the fungus spreads throughout its vascular system, cutting off its water supply and nutrients. There are several different ways to identify if a tree has been infected. “Infected ‘ōhi‘a trees may have individual branches or entire canopies of recently dead and still attached brown leaves. The tree's sapwood may have dark and unusual staining and a fruity odor, though signs of the fungus may not be visible on the outside of the tree” (Rapid ‘Ōhi‘A Death - Hawaiʻi Volcanoes National Park (U.S. National Park Service), n.d.). This is because the fungus grows inside the tree, invisible from the outside.
Two types of fungus cause ROD: C. lukuohia and C. huliohia. C. lukuohia is the more aggressive species, and C. huliohia is less aggressive, though both are fatal (Rapid ’Ohi’a Death: Overview, n.d.). The fungus can be spread in soil, air, and water, and infects a tree by entering through a wound in the bark (Oahu Invasive Species Committee, 2024). In 2019, aerial surveys on the Island of Hawai`i showed that more than 175,000 acres of forest contained ‘Ōhi‘a with ROD (Rapid ’Ohi’a Death: Overview, n.d.). One or both strains of the ROD-causing fungus have been recently found on Hawai`i island, Kaua`i, Oahu, and Maui (Oahu Invasive Species Committee, 2024).
Some factors that may influence the spread of fungi are human activity, animals, and beetles. Humans are a factor since they may unknowingly use infected wood or contaminated tools. A species of beetle is attracted to infected ‘Ōhi‘a trees; when they burrow into the trees they create a fine dust containing fungal spores that can be carried by the wind. The contaminated dust mixes with the soil, creating another opportunity for disease transmission (Rapid ’Ohi’a Death: Overview, n.d.)
Although ‘Ōhi‘a trees are not endangered, their well-being impacts many other species. They provide soil stabilization, shade for crops, watersheds, and habitats for native species, and the blossoms have even been used for medicinal purposes (Friday and Herbert). ‘Ōhi‘a trees comprise about 80% of native Hawaiian forests, and the loss of forests due to ROD allows invasive plants to spread rapidly. A decline in native plants means that there will be less food and shelter available for native animals, ultimately threatening these animals with endangerment or extinction (Camp et al., 2019).
Importance in Hawaiian Culture
‘Ōhi‘a trees have been so important in Hawaiian history that mentions of them have been woven into legends and songs. One such legend is that of ‘Ōhi‘a and Lehua. While there are many iterations of the story, at their core they remain the same. So one version of the story goes, that long ago, there lived a girl named Lehua. She was beautiful and kind, and beloved by everyone. Her gentle spirit drew the attention of many, especially that of a young warrior, ‘Ōhi‘a. ‘Ōhi‘a was strong and fierce, with a brave heart. In the middle of their island was a dense forest, with trees that reached towards the skies and many birds and creatures and forest spirits dwelling there. At night as the moon bathed the forest floor with her light and the stars shone above, ‘Ōhi‘a would whisper sweet melodies on his flute and walk the forest paths. Following the soft music, Lehua would meet Ōhi'a and they would walk together, admiring the beauty of the night. In the mornings they would listen to the birdsong and feel the warm rays of the sun, and Lehua would gather flowers to bring back to their village. And so they passed their days with great devotion to each other, and all the creatures and villagers and gods witnessed their love. Pele, the goddess of volcanoes, saw how much ‘Ōhi‘a cared for Lehua, and grew jealous. Her fiery temper burned darkly within her, filling her heart with rage. One day, Pele approached ‘Ōhi‘a, and demanded that he be hers. Although he didn't want to upset the goddess, ‘Ōhi‘a rejected her, saying his heart belonged to another. As he spoke, Lehua arrived, and Pele became more enraged. The jealous goddess unleashed her wrath, sending waves of lava flowing towards the couple. Devoted to the end, ‘Ōhi‘a held Lehua in his arms and raised her above the flames that surrounded them. The many spirits and creatures of the forest who cared for the couple wanted to help but had no power to stop Pele’s fury. The lava drew closer, beginning to creep up ‘Ōhi‘a’s legs. Lehua wept for her beloved, for their life and future that was being consumed by flame, and all the forest spirits mourned with her. Although they could not save them, the spirits gathered to try and use their power. As the fire enveloped the couple, ‘Ōhi‘a’s legs turned to bark, his body becoming the trunk of a strong tree, his arms turning to branches. Still held aloft, the lovely Lehua transformed into blossoms, red and gold like fiery sparks. The two lovers remained entwined, their love so strong that it lasted even after death, transformed into new life.
And so the story tells of the creation of the ‘Ōhi‘a Lehua tree, of the resilience it has, and its importance to the Hawaiian islands. As ‘Ōhi‘a and Lehua represented love and life for the forest spirits, so too the ‘Ōhi‘a tree is a source of shelter and life for many species of plants and animals. It is said that if you were to pick a Lehua flower from the tree, the skies would weep with rain at the lovers’ separation.
Although there is no cure or treatment to prevent ‘Ōhi‘a trees from ROD, combined efforts are working together to research the disease and protect Hawaiian forests. While things may seem dire for ‘Ōhi‘a trees, there are still reasons to remain hopeful. For example, “the fact that some ‘Ōhi‘a survive in forests on the Big Island in the presence of ROD indicates that some trees might possess natural resistance” (Rapid ‘Ōhi‘a Death - Don't Move Firewood, 2024).
Further Information
Below are links to a couple of sites providing more information on ROD and efforts done to combat it.
https://www.akakaforests.org/programs/ ‘Ōhi‘a-disease-resistance-program
The ʻŌhi‘a Disease Resistance Program (ODRP) was established in 2018 to identify ROD-resistant ‘Ōhi‘a with the goal of producing disease-resistant plants for restoration of native forests, landscaping, and the perpetuation of ‘Ōhi‘a in our biocultural landscapes.
“We strive to provide the latest information and recommendations for dealing with ROD and helping prevent the spread of this deadly tree disease. We work with schools, communities and event organizers to share about the importance of ‘Ōhi‘a and the threat posed by ROD”.
https://gms.ctahr.hawaii.edu/gs/handler/getmedia.ashx?moid=66598&dt=3&g=12
Rapid ‘Ōhi‘a Death Strategic Response Plan 2020-2024
Works Cited
Camp, R. J., LaPointe, D. A., Hart, P. J., Sedgwick, D. E., & Canale, L. K. (2019). Large-scale tree mortality from Rapid ‘Ōhi‘a Death negatively influences avifauna in lower Puna, Hawaii Island, USA. Ornithological Applications, 121(2). https://doi.org/10.1093/condor/duz007
Fortini, L. B., Kaiser, L. R., Keith, L. M., Price, J., Hughes, R. F., Jacobi, J. D., & Friday, J. (2019). The evolving threat of Rapid ‘Ōhi‘a Death (ROD) to Hawai‘i’s native ecosystems and rare plant species. Forest Ecology and Management, 448, 376–385. https://doi.org/10.1016/j.foreco.2019.06.025
Friday, J.B., Herbert, D.A., 2006. Metrosideros polymorpha (‘Ōhi‘a lehua). In: Elevitch, C.R. (Ed.), Traditional Trees of Pacific Islands. Permanent Agriculture Resources, Holualoa, HI.
Moʻolelo of ‘Ōhi‘a & Lehua • Manoa Heritage Center. (2023, February 22). Manoa Heritage Center. https://www.manoaheritagecenter.org/moolelo/native-plants/ ‘Ōhi‘a-lehua/%CA%BBohi%CA%BBa-lehua-adapted-from-the-goddess-pele-by-joe-mullins/
Oahu Invasive Species Committee (OISC). (2024, February 21). Rapid ‘Ōhi‘a Death - Oahu Invasive Species Committee (OISC). https://www.oahuisc.org/species/rapid- ‘Ōhi‘a-death/
Rapid ‘Ōhi‘a Death - Hawaiʻi Volcanoes National Park (U.S. National Park Service). (n.d.). https://www.nps.gov/havo/learn/nature/rapid-ohia-death.htm
Rapid ’Ohi’a Death: Overview. (n.d.). https://cms.ctahr.hawaii.edu/rod/THE-DISEASE
Rapid ‘Ōhi‘a Death - Don't Move Firewood. (2024, February 21). Don’t Move Firewood. https://www.dontmovefirewood.org/pest_pathogen/ceratocystis-wilt-ohi-html/
The Battle to Slow Rapid ‘Ōhi‘a Death in Hawai‘i . Forest Service National Website. (n.d.). https://www.fs.usda.gov/detail/r5/communityforests/?cid=fseprd1091868
Yuen, L. (2020, June 15). ’ōhi’a-lehua legend. Ke Ola Magazine. https://keolamagazine.com/culture/ ‘Ōhi‘a-lehua-legend/
