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
Nin Jiom Pei Pa Koa for "Mother and Son Brand", referring to the brand's logo) in Malaysia and Indonesia, also acronymed as OBIDA (as in "Obat Ibu dan Anak") in the latter country. The formula for "pei pa koa" was reportedly created by Dr. Ip Tin-See, a Qing Dynasty physician born about 1880. Yang Jin, a county commander, asked Doctor Ip to treat his mother's persistent cough. They were so impressed that they created a factory to mass-produce it. In 1946, the Yang family sold the business to Tse Sui-Bong, a medicine practitioner, who founded the Nin Jiom Medicine Manufactory. The company was formally incorporated