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
KOA (AM) heard on KOA include Bob Martin, Don Zimmer, Gus Mircos, Alex Stone, and Steffan Tubbs, Rollye James and George Weber. The late Rick Barber was heard for 30 years on KOA. Consumer advocate Tom Martino and former FEMA official Michael D. Brown were KOA hosts until they switched to sister station KHOW. Radio host Alan Berg broadcast his talk show from the station, but was shot and killed by members of the white supremacist group The Order on June 18, 1984. Another host from an earlier era was Leigh Kamman, who hosted jazz programs during World War II. Kamman returned