Wattle trees are of the genus Acacia, in the Mimosa family, and common throughout Australia, where there are over 600 different species. Varying in size, they may grow as low shrubs, or tall trees. Remarkably adaptable, they grow from rainforest areas to coastal heaths and remote, parched desert country.
During the last century, natural vegetation in the hills of the Western Ghats was replaced on a massive scale with the introduction of non-native tree species. In Kerala, black wattles were planted massively by the Europeans for the purpose of fire wood. Wattle trees now seem a part of the hill-station landscape though they are actually dangerous invaders. These plantations of exotic trees have been one of the major factors in restricting the flow of streams in the dry season.