Part of the myrtle family, eucalyptus trees are a diverse genus of flowering trees and shrubs native to Australia. They were introduced to the rest of the world following the first expedition of James Cook, which began in 1768. After making scientific observations, recording a transit of Venus across the sun in 1769 in Tahiti, Cook set sail for home. Heading westward, he took time to circle New Zealand and stop on the eastern coast of Australia.
A very diverse species, they have many uses which have made them economically important trees, and have become a cash crop in poorer areas such as Timbuktu, Africa and the Peruvian Andes.
I’ve walked past one of these unique trees on a daily basis for about the last five years. I’m not blind, and I did notice it, and once I stopped to take some pictures of its unique multi-colored bark.
For some reason I thought it was an Ohia tree, a flowering evergreen that is part of the Myrtle family and grows only in Hawaii.
I grew up in Southern California, a place where a wide variety of the genus, eucalyptus exists, so I can’t explain the misidentification. It wasn’t until I decided to look further into the issue of the multi-colored trunk that it became clear. I picked a leaf and rubbed the glossy, green foliage between my palms, and then, the familiar fragrance. Of course, it’s a eucalyptus and it stands just 15’ to 20’ from my exercise path along the school yard in Makawao.
Due to its fast growth, the foremost benefit of these trees is their wood. They provide many desirable characteristics for use as ornament, timber, firewood and pulpwood. It is also used in a number of industries, from fence posts and charcoal to cellulose extraction for biofuels. Fast growth also makes eucalypts suitable as windbreaks and to reduce erosion.
Eucalyptus oil is also much sought after. It is readily steam distilled from the leaves and can be used for cleaning agents and as an industrial solvent. It is also used as an antiseptic, for deodorizing, and in very small quantities, in food supplements, especially sweets, cough drops, toothpaste and decongestants. It has insect repellent properties, and is an active ingredient in some commercial mosquito repellents. Although, the oil is highly flammable, an aid to bushfires, adding fuel, allowing flames to travel easily through the oil-rich air of the tree crowns. The Oakland, CA fire of 1991 destroyed 3,000 homes and 25 people died fighting and trying to escape the flames. In many cases, eucalyptus trees located near many of the homes were blamed, their dried oils and sap detonated and intensified the fire in some cases.
This unique plant is a tall tree that comes to us from the Philippines, and it is commonly known as the rainbow eucalyptus, Mindanao gum, or rainbow gum. Since its introduction, it is found in New Britain, New Guinea, Seram, Sulawesi and Mindanao, and is the only eucalyptus species with a natural range that extends into the northern hemisphere. It thrives in mostly tropical forests, places that typically get a lot of rain. This is why such a large specimen is located near my home. Makawao is located at 1,500 feet above sea level and is on the windward side of the island of Maui. Trade winds buffet this part of the island, often spraying the surrounding area with a mist every afternoon, year round.
Although this tree looks like the trees I knew in California, the unique multi-hued bark, which is the most distinctive feature of the tree, distracted me from further inspection. Patches of outer bark are shed annually at different times, showing a bright green inner bark. This then darkens and matures to give blue, purple, orange and then maroon tones. The previous season’s bark peels off in strips to reveal a brightly colored new bark below.
Known as Eucalyptus deglupta, it is cultivated as an ornamental tree. It is used for planting in tropical and subtropical gardens and parks. The showy multi-colored streaks that cover the trunk are a distinctive landscape design element.
In the U.S., rainbow eucalyptus grows in the frost-free climates found in Hawaii and the southern portions of California, Texas and Florida. In the Hawaiian Islands, rainbow eucalyptus can be found in the up-country of Kaloko in Kona, on the Big Island; at the Dole plantation near Wahiawa on Oahu; and, where I took most of my images, just off Hana highway near mile marker 7, and close to Na’ili’ili Falls on Maui. This is a small grove of trees that appear to have been planted in straight rows, close to and nearly parallel to the highway. Although, after doing some additional inspection of the surrounding area, there are more rainbow eucalyptus nearby. There is limited parking along the road and it’s an easy and worthwhile walk.