Acacia koaia Acacia koaia Acacia koaia, known as koaia or koaie in Hawaiian, is a tree in the pea family, Fabaceae, that is endemic to Hawaii. It is closely related to "koa" ("A. koa"), and is sometimes considered to be the same species. "Acacia koaia" is usually distinguished by growing as a short (rarely more than ), broad, gnarled tree; having the seeds longitudinally arranged in the pod; shorter, straighter phyllodes; and much denser wood. A population on the northern coast of Kauai may be intermediate, but the relationships have not been worked out. "Koaia" wood is claimed to be very different
Acacia koa used by ancient Hawaiians to build "waa" (dugout outrigger canoes) and "papa hee nalu" (surfboards). Only "paipo" (bodyboards), "kikoo", and "alaia" surfboards were made from koa, however; "olo", the longest surfboards, were made from the lighter and more buoyant "wiliwili" ("Erythrina sandwicensis"). The reddish wood is very similar in strength and weight to that of Black Walnut ("Juglans nigra"), with a specific gravity of 0.55, and is sought for use in wood carving and furniture. Koa is also a tonewood, often used in the construction of ukuleles, acoustic guitars, and Weissenborn-style Hawaiian steel guitars. B.C. Rich used koa on some