Koa is a spectacular hardwood growing only in the Hawaiian islands but is possibly the most popular hardwood in the world. Due to its popularity and lack or growing space, Koa can be difficult to find. It has a wide range of colors and is one of the finest hardwoods available.
Color can be highly variable, but tends to be medium golden or reddish brown, similar to Mahogany. There are usually contrasting bands of color in the growth rings, and it is not uncommon to see boards with ribbon-like streaks of color. Boards figured with wavy and/or curly grain are also not uncommon.
Grain & Texture
Grain is usually slightly interlocked, and sometimes wavy. Uniform medium to coarse texture.
Koa is widely considered to be the most beautiful and useful of Hawaii’s native hardwoods, and along with Monkey Pod and Mango, it is the most common Hawaiian species to be imported into the lower 48 United States.
Visually, Koa has been compared to Mahogany, while in terms of working and mechanical properties, it has been compared to Walnut. Because of its nearly equal tangential and radial shrinkage, (its T/R Ratio is only 1.1), Koa tends to be quite stable regarding environmental changes in humidity.
Although Koa is naturally quite abundant on the islands of Hawaii, most Koa forests have been cleared for grazing pastures; and since young Koa seedlings are edible for grazing animals, most new trees are prevented from growing to lumber-harvestable size. As a result, mature Koa trees are either scarce, or in hard-to-access mountainous locations, and the price of Koa is likely to only increase further in the future. Australian Blackwood (Acacia melanoxylon) is considered to be a more sustainable, and visually/mechanically similar substitute.