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Koa

Acacia koa
Gray is Hawai`i's most prized tree species. The koa is a large, evergreen broad leaf tree and the only Acacia endemic to Hawai'i. It is found from 600 to 7,000 feet on all of the main islands except Ni`ihau and Kaho`olawe. Koa occurs in both pure and mixed forest stands and is frequently found growing with the native `ōhi`a (Metrosideros polymorpha).

These small koa trees on the right  were found along side the road on Koloko Drive on the slopes above Kailua-Kona. Larger koa trees can be seen at Hawai'i Volcanoes National Park.

No discussion of the koa tree would be complete without mentioning its importance to the Hawaiian rain forest. It is a nitrogen-fixing species. In dense, pole-size stands, nitrogen-rich koa foliage can account for 50 to 75 percent of the leaf-litter. Mature koa is needed for bird habitat; our forest birds do not use young, pure stands of koa, but do use the old, mixed-species stands adjacent to young stands.

 

Koa Leaves

 

Koa are large trees up to 100 feet tall and spreading 40-80 feet. On mature trees, what appear to be sickle-shaped leaves are actually modified leaf stalks called phyllodes, which allow more effective drought resistance.True leaves, which facilitate rapid growth, are similar to those of koa-haole or mimosa and generally occur during the seedling state. Old trees usually bear only laurel green phyllodes, but sometimes true leaves appear on the trunk or lower branches, or after wounding. Flowers appear as small pale yellow "puffballs."

The koa's fine straight trunk made the wood a favorite for canoes in ancient times. Hawaiians also used the wood for surfboards, storage containers (but never for food storage), weapons, and tools.


Today, this lustrous wood is used for cabinets, veneer, and crafts. It frequently occurs with a curly grain and ranges in color from golden-blonde through most common orange-red to deep purples.

The interior walls of Hulihe'e Palace were originally koa.The doors are made of koa and much of the Palace furniture was crafted from koa.





Trees used in Hulihe`e Palace and its furnishings: Koa, Kou, `Ōhi`a Lehua
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