Acacia koa Acacia koa Acacia koa is a species of flowering tree in the pea family, Fabaceae. It is endemic to the Hawaiian Islands, where it is the second most common tree. The highest populations are on Hawaii, Maui and Oahu. Its name in the Hawaiian language, koa, also means brave, bold, fearless, or warrior. Koa is a large tree, typically attaining a height of and a spread of . In deep volcanic ash, a koa tree can reach a height of , a circumference of , and a spread of . It is one of the fastest-growing Hawaiian trees, capable of
Hawaiian tropical rainforests milo ("Thespesia populnea") for the past 1,000–2,000 years. The Polynesian-introduced noni ("Morinda citrifolia"), pia ("Tacca leontopetaloides"), and kī ("Cordyline fruticosa") are also common in this zone. Other native species include pololei ("Ophioglossum concinnum"), ākia ("Wikstroemia" spp.), loulu fan palms ("Pritchardia" spp.), ōhia lehua ("Metrosideros polymorpha"), and lama ("Diospyros sandwicensis"). Mixed mesic forests, at on the windward slopes of the large islands in addition to the summit of Mount Lānaihale on Lānai, receive of rainfall annually and thus may not be true rainforests. The forest canopy, dominated by koa ("Acacia koa") and ōhia lehua ("Metrosideros polymorpha"), is somewhat open, but tree