There appears to be a correlation between rapid ʻōhiʻa death and hooved animals, such as pigs and horses, according to a research group.
ROD was first reported in 2013 when two fungi were found to be killing the trees.
Areas with a bigger population of hooved animals — also known as ungulates — have higher rates of ʻōhiʻa mortality.
Researchers speculate that the hooved animals are injuring the trees.
"There’s likely some kind of interaction with the animals and wounding of the trees which is leading to the increased levels of mortality in the places with ungulates as opposed to ungulate-free areas," said Ryan Perroy, an associate professor of geography and environmental science at the University of Hawaiʻi at Hilo — he's also lead investigator of the study.
Perroy is working with colleagues from the National Park Service, U.S. Forest Service and U.S. Department of Agriculture.
When an animal injures a tree, fungi can enter through the wound and damage its health, similar to an open wound on the human body and bacteria.
Hawaiʻi Volcanoes National Park crews have set up fencing around ʻōhiʻa trees to prevent animals from causing more damage.
