The Koa tree is one of the tallest trees in Hawai'i, often reaching several hundred feet in height. The reddish-orange and brown wood is prized for many products and was used by the Hawaiians to build canoes - many of which were built from a single, straight Koa trunk. The trees can reach a diameter of over 10 ft and are resistant to salt water, making them perfect for boat building.
Koa leaves are unusual in that the juvenile plants first leaves look totally different than a mature plant. The top Koa picture on this page shows the typical crescent shape leaves of a mature plant, while the picture just under it shows the leaves of a seedling. You can easily see that the immature leaves are not only different but are also compound leaves while the mature leaves are not compound. The mature Koa leaves are flat and strong. Dry leaves can be very slippery to walk on as they tend to resist water.
The flowers of the Koa are small yellow and puffball like. The Koa tree is a protected tree in Hawai'i. Because the wood is so prized for all sorts of uses it is now illegal to kill any living Koa tree, and only dead trees may be used for any type of woodworking.
You can find Koa all over the Big Island, but huge stands of Koa are easy to find in the Volcano area, including Bird Park and the National Park itself.
The Koa In Ancient Hawaiian Medicine
Both the bark and the crescent leaves were used in various medicinal preparations including birth control.