Melochia umbellata

A native to India this tree was introduced for reforestation use.  It is a weedy fast growing tree.  In India it is used to provide shade for crop plants but in Hawaii their rapid growth allows them to crowd out native species and their small winged seeds are spread by winds allowing them to cover wide areas, making it a pest plant.  The wood is soft and deteriorates rapidly after being cut.  However at the zoo, the leaves and young shoots are used in some of our animal's diets.