A new video, “Protecting Hawaiʻi’s Native Forests,” shows how ʻōhiʻa trees can thrive when animals are kept out of native forests.
The film from the University of Hawaiʻi at Mānoa’s College of Tropical Agriculture and Human Resilience shows land across Hawaiʻi Island that’s been fenced off for native plant conservation. It illustrates the stark difference in ʻōhiʻa tree health between the land inhabited by animals and the land that has been blocked off.
J.B. Friday, an extension forester at UH, was the lead on the project. He explained that the research team behind the video surveyed the lands and concluded that animals, especially those with hooves and tusks, were damaging ʻōhiʻa trees, making them vulnerable to the disease.
“When you see animal damage to trees, cattle stripping, pigs tearing up roots, you also see a lot of mortality. We started seeing these patterns, that there would be an area with a lot of disease, and it would abruptly stop, and it would stop at a fence line,” Friday said.
ʻŌhiʻa trees make up roughly 80% of native forest in Hawaiʻi, and they play an essential role in watershed protection and overall ecosystem function. Rapid ʻōhiʻa death (ROD) was first identified in the state in 2014, and has since killed an estimated 1 million trees on Hawaiʻi Island alone.
The disease can be carried through sawdust, on the hooves and tusks of animals, and through the wind. If these infected surfaces come in contact with an exposed wound on an ʻōhiʻa tree, that tree will become infected.
“You have the same forest on both sides of the fence, but one side of the fence was managed to keep the animals out, and the other had a lot of animals in it. The disease would go up to the fence line and stop. You'd only see a few trees inside the fence with it, but hundreds of trees outside the fence getting the disease,” Friday said.
Friday said he doesn’t think fencing off areas is the ultimate solution. He added that many folks, including Justin Lee, a hunter featured in the video, rely on the animals as a food source.
“I think at the very end, it has to be balanced, because there is a lot of people that live off of the pork that run around this island,” Lee said in the video. “But what's more important? Is it that? Or is it the forest that we live amongst, that we count on for our water, that we count on for so much more than just food?”
Friday said he believes there can be a middle ground. Areas with large native plant populations could be marked off, while land with more animals and fewer plants could be saved for hunting.
“Protecting the forest from animals is one thing that we can do, but there are other things that are going to injure trees and spread disease that we can't do anything about,” Friday said. “Forest health is like your own health. You take care of it the best you can, but then something happens out of your control and you get diseases anyway. But this is something that we can do.”
