Acacia koa for up to 25 years. Scarification is needed before "A. koa" seeds will germinate. Koa is endemic to the islands of Hawaii, Molokai, Maui, Lānai, Oahu, and Kauai, where it grows at elevations of . It requires of annual rainfall. Acidic to neutral soils (pH of 4-7.4) that are either an Inceptisol derived from volcanic ash or a well-drained histosol are preferred. Its ability to fix nitrogen allows it to grow in very young volcanic soils. Koa and ōhia lehua ("Metrosideros polymorpha") dominate the canopy of mixed mesic forests. It is also common in wet forests. The koa's trunk was
Acacia sensu lato fragrant timber used for ornaments. "A. seyal" is thought to be the shittah-tree of the Bible, which supplied shittim-wood. According to the Book of Exodus, this was used in the construction of the Ark of the Covenant. "A. koa" from the Hawaiian Islands and "A. heterophylla" from Réunion are both excellent timber trees. Depending on abundance and regional culture, some "Acacia" species (e.g. "A. fumosa") are traditionally used locally as firewoods. It is also used to make homes for different animals. In Indonesia (mainly in Sumatra) and in Malaysia (mainly in Sabah), plantations of "A. mangium" are being established to