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 in 1962, and continue to manufacture and sell the product worldwide. "Pei pa koa" had annual sales of HK$350 million in 2014. A study at the China Academy of Traditional Chinese Medicine published in a 1994 article, "Pharmacological studies of nin jion pei pa koa", states that Nin Jiom Pei Pa Koa had significant cough relieving and sputum removing effects. In four acute or sub-acute inflammatory models, the anti-inflammatory effect was marked.." "Pei pa koa" is made up of a blend of herbal ingredients including the fritillary bulb ("Bulbus fritillariae cirrhosae", 川貝母), loquat leaf ("Eriobotrya japonica", 枇鈀葉), ladybell root ("Adenophora