Acacia mearnsii (black wattle).
Black wattle (Acacia mearnsii) is one of the most widespread, and significantly invasive alien trees in South Africa. It has been introduced as a useful tree for its commercial source of tannin or a source of firewood for local communities. In areas where it has been introduced, it is often considered a weed, and is seen as threatening to native habitats by competing with indigenous vegetation, replacing grass communities, reducing native biodiversity and increasing water loss from riparian zones.