A lot of species of acacia will make a bow...but it twists like mad, so dry it well first. Also, you probably have a lot of invasive Australian pine (Casaurina) growing there. Some subspecies of it will make a good bow if backed. Koa I would imagine to make a bow as well! What the other guys said is true though, guava is a great bow wood. Just take the bark off it and don't violate the sap wood layer and it will kick some serious arse ;-)