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) 1927, increased to 12,500 watts. KOA became an NBC affiliate in 1929, and the network took over operation of the station from GE shortly thereafter. On July 7, 1934, power was raised to the current level of 50,000 watts. In 1941, NBC, which had been operating the KOA and KGO in San Francisco for GE since October 1, 1929, also took over ownership of the stations. NBC continued to own KOA until June 1953 when it sold the station to Metropolitan Television Company, whose principal stockholder was Bob Hope. GE repurchased the station in 1968 and continued to own it