Hibiscadelphus giffardianus viscosa"), and naio ("Myoporum sandwicense"). "H. giffardianus" is a small tree, reaching a height of and trunk diameter of . Hibiscadelphus giffardianus Hibiscadelphus giffardianus (Kilauea hau kuahiwi) is a species of flowering plant in the mallow family, Malvaceae, that is endemic to the Big Island of Hawaii. It is believed to be extinct in the wild; any remaining plants are threatened by habitat loss. Cultivated plants exist in Hawaii Volcanoes National Park. It inhabits mixed mesic forests on the slopes of Mauna Loa at elevations of . Associated plants include ōhia lehua ("Metrosideros polymorpha"), koa ("Acacia koa"), mānele ("Sapindus saponaria"),
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