Hawaii’s native forests threatened

  • More than two dozen endemic Pritchardia palms (loulu) found no place on Earth are on the verge of extinction due to rats and pigs. We can help avoiding this if we plant them in our parks and gardens. (Voltaire Moise/Special to West Hawaii Today)

Like so much of the tropical world, the forests of Hawaii’s coastal and mountain regions are under assault. Over the years we have seen massive timber clearing for pasture and sugarcane. Now thousands of acres have been abandoned and are being naturally reforested with non native species like guava, albizia, African tulip, gun powder trees (Trema orientalis) and scores of others. These trees are sometimes called weeds, but remember that they are pioneer species attempting to heal the wounds created by nature and human activities. On the positive side, they continue to supply oxygen, sequester carbon and minimize erosion. On the negative side, they are not native.

When it comes to native forests, large portions of the Big Island have been protected in national park and state forest watershed. Unfortunately, these too are under assault by nature. Global warming, along with new diseases like rapid ohia death and koa wilt are killing some of our most revered trees. The natural world seldom stays the same, as we are reminded by COVID-19. We can attempt to control nature by minimizing the introduction of insects and diseases. We can avoid introducing plant or animal species that may have a negative effect on our native forests, but things will never be like it was in the good old days before humans arrived here.


Climate change is having a tremendous impact. As temperatures rise, high elevations are being invaded by mosquitoes, thus threatening our endemic birds with disease. Global warming is no longer a theory and is being accepted as fact by most scientists and governments. This will affect much of the tropics including our Islands by causing more extremes like drought, floods and severe storms. It is not all doom and gloom even though it seems like it after more than two months in COVID-19 lockdown! We may not be able to do much about other parts of the world, but here at home we as individuals are either part of the solution or part of the problem. Cutting down trees is a step in the wrong direction. Planting trees is a step in the right direction. That can make a big difference, since trees not only produce oxygen, they supply shade, act as windbreaks and lock up the carbon that is the main cause of global warming.

Many of Hawaii’s forests and forest watersheds are threatened, even with all the rhetoric about saving rainforests. In East Hawaii, many forest areas are subdivided into small lots of one to three acres. Unless the owners of the land really commit to protecting the forested lots, they are bulldozed and flattened. In West Hawaii, much of our uplands are still covered with native forest.

Where our family lives in Kaloko Mauka, it is sparsely populated, and the gardens are a fascinating mixture of hydrangeas, hoawa, calatheas, camellias, koa, kopiko and many other natives. Since the COVID lockdown we have been doing a lot of hiking here and really appreciating its uniqueness. The area abounds with ancient ohia (Meterosideros polymorpha) and gigantic treeferns, some of which are 15 feet or more. These ferns may be over 100 years old since the trunks only grow 2 to 3 inches per year. The native forest contains many rare and endangered species that local residents are committed to protect through the County Tax Department that allows residents to dedicate their land to forest. This program allows residents to protect this important and unique watershed. This region between 2,000 and 5,000 feet is actually cloud forest. Up to 40% of the precipitation comes from the mists that abounds. When the cloud forest is cleared, the area dries.

The cloud forests of Kaloko Mauka are the home of the Hawaiian hawk, apapane, iiwi, elepaio, amakihi and many other endemic and exotic birds. Kaloko Mauka has been identified as essential wildlife habitat and forest watershed. This is essential if our island is to have the rainfall and watershed needed to supply communities at lower elevations. It is a rare type of forest and yet is readily accessible being only 15 minutes from Kailua.

Some folks feel that East Hawaii has plenty of rain, so forests are not necessary. However, forests are like big sponges. They slow down flooding rains, and give up moisture so that streams continue to run when rainfall is light. Without forests, flooding and drought as well as severe erosion becomes the norm. Also, grasslands are infamous fire hazards during drought times.

Tropical forests include not only trees but under story palms, orchids and ferns. Many plants like our endemic pritchardia palms are endangered due to the destruction of the forests. We must protect our unique natives and at the same time recognize that many nonnatives have value as well. Fortunately, Hawaii is becoming a kind of Noah’s Ark for rare plants thanks to the efforts of the Hawaii Island Palm Society, Bamboo Society, Sierra Club, Nature Conservancy, Outdoor Circle, Moku o Keawe, Hawaii Island Land Trust and other concerned groups.


Remember, not only is it vital to protect our remaining Hawaiian forests, but to reforest those abandoned cane lands of Hamakua, Puna, Kau and Kohala thus ensuring valuable forest resources for future generations.

For more information on forest planting and management, contact UH Extension Forester, J.B. Friday at (808) 959-9155 when COVID-19 lockdown is pau.

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