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 melanoxylon 20%. It may also be used for producing decorative veneers. The tree's twigs and bark are used to poison fish as a way of fishing. This tree can also be used as a fire barrier plant, amongst other plants, in rural situations Plain and figured Australian blackwood is used in musical instrument making (in particular guitars, drums, Hawaiian ukuleles, violin bows and organ pipes), and in recent years has become increasingly valued as a substitute for koa wood. Acacia melanoxylon Acacia melanoxylon, commonly known as the Australian blackwood, is an "Acacia" species native in South eastern Australia. The species is