HILO, Hawaii (KHON2) – A new study out of University of Hawaii Hilo suggests that ʻōhiʻa seedlings can survive for at least a year in areas that are infected with Rapid Ōhiʻa Death, or ROD.

The study, published May 8 in Restoration Ecology, is authored by scientists from the U.S. Geological Survey and the Hawaii Cooperative Studies Unit at U.H. Hilo.

ROD is a fungal disease that is known to infect the vascular systems of ʻōhiʻa, causing water to stop moving up to the crown of the tree.

“ROD has the potential to cause major ecosystem disturbances that will negatively impact water supply, cultural traditions, natural resources, and quality of life,” said USGS Director Jim Reilly.

To test how the seedlings would survive in areas where ROD is prevalent, researchers planted them directly underneath adult ʻōhiʻa trees that tested positive for the disease.

Some seedlings were planted in survival pots that were fenced in from animals and invasive plants, while others were left out in areas that had no protective measures at all.

According to the study, seedlings that did not survive were taken back to the lab to determine whether they had been infected with ROD.

None of the dead seedlings tested positive for ROD, indicating that ʻōhiʻa can survive in ROD-infected forests if they are protected from wild animals and invasive plants.

​The study revealed that the seedlings were also six times more likely to die if the surrounding weeds weren’t being maintained.

This suggests that controlling invasive plants and animals has a greater impact on the health of ʻōhiʻa than being exposed to ROD.

The results are encouraging for two reasons, UH Hilo Extension Forester J.B. Friday says.

“First, it means that even in forests with invasive trees and shrubs, ʻōhiʻa may possibly be re-established. And second, it means that in our high-elevation, pristine native forests, natural ʻōhiʻa regeneration could be possible, even in forests hit by ROD, if those areas are protected,” said Friday. 

To read the full study, click here.

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