The ʻōhiʻa (metrosideros polymorpha) tree, which is endemic to Hawaiʻi, may be easier to repopulate than previously thought. New University of Hawaiʻi at Mānoa research provides encouragement and guidance to those wanting to reestablish ʻōhiʻa populations in areas that have suffered significant mortality due to the recent spread of the fungal pathogen known as rapid ʻōhiʻa death.
The study is the culmination of nearly 40 years of research on Hawaiʻi Island, spearheaded by School of Life Sciences Emeritus Professor Dieter Mueller-Dombois. The research focuses on portions of an intact, mature native lowland rainforest located in the Puna District, which were deforested in the mid-1980s.
Researchers compared the aboveground carbon accumulation of trees that were replanted in the deforested area (secondary succession) as compared to trees that were planted to new land created by lava nearby (primary succession). Higher aboveground carbon accumulation is one indicator of healthy trees.
Results countered previous research that ʻōhiʻa is a slow-growing species. In addition, ʻōhiʻa planted in second-growth forests were characterized as highly productive and resilient to disturbance. Results indicated that mature ʻōhiʻa trees planted through primary succession provided a high level of aboveground carbon accumulation, while ʻōhiʻa trees planted through secondary succession showed approximately half of the carbon accumulation than from primary succession.
Researchers also discovered that ʻōhiʻa trees were able to be reproduced quickly, as long as factors such as non-native plant invasion did not disrupt their development through competition.
ʻŌhiʻa trees are only found in Hawaiʻi, and are the subject of many Native Hawaiian traditions that refer to the tree as being sacred to Pele (goddess of volcanoes and fire) and Laka (goddess of hula). According to the Department of Land and Natural Resources, on Hawaiʻi Island alone, there are an estimated 290 million mature ʻōhiʻa, more than any other native tree species.
The study, “Aboveground carbon accumulation by second-growth forests after deforestation in Hawaiʻi,” was published in Ecological Applications. Along with Mueller-Dombois, researchers included Richard Flint Hughes and Jonathan D. Marshall from the Institute of Pacific Islands Forestry, U.S. Forest Service Pacific Southwest Research Station; Dennis Grossman from the California Strategic Growth Council; and Travis G. Sowards from Brigham Young University.
This work is an example of UH Mānoa’s goals of Excellence in Research: Advancing the Research and Creative Work Enterprise (PDF) and Building a Sustainable and Resilient Campus Environment: Within the Global Sustainability and Climate Resilience Movement (PDF), two of four goals identified in the 2015–25 Strategic Plan (PDF), updated in December 2020.
