Alien Tree Invasion in South Africa Status and Impacts on Water in Strategic Water Source Areas

Clearing woody invasive alien plants (hereafter “alien trees”) in all four of the study catchments could release over 100 mm per annum if they are restored to a native treeless ecosystem, such as grasslands, shrublands or wetlands. Even restoring to a treed ecosystem, such as a forest (where appropriate), produces water gains compared to alien tree invasions of wattle, pine, gum and poplar (by ~20 mm per annum).