Koa wilt it starts to produce microconidia, eventually clogging the xylem. Once the Koa tree dies, the fungus invades all tissues and, upon reaching the dead plant surface, sporulates profusely producing macroconidia and chlamydospores. The fungus can survive saprophytically in the soil, as either mycelium or as any of its three spore types mentioned. The chlamydospores, as the resting spores, survive the longest in the soils, usually under cold conditions. Koa trees occupy dry to mesic areas on the islands of Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi in elevations of 80 to 8,000 feet with 0 to 100 inches of rain.
Acacia koa used by ancient Hawaiians to build "waa" (dugout outrigger canoes) and "papa hee nalu" (surfboards). Only "paipo" (bodyboards), "kikoo", and "alaia" surfboards were made from koa, however; "olo", the longest surfboards, were made from the lighter and more buoyant "wiliwili" ("Erythrina sandwicensis"). The reddish wood is very similar in strength and weight to that of Black Walnut ("Juglans nigra"), with a specific gravity of 0.55, and is sought for use in wood carving and furniture. Koa is also a tonewood, often used in the construction of ukuleles, acoustic guitars, and Weissenborn-style Hawaiian steel guitars. B.C. Rich used koa on some