invasiveness of alien trees

There has been a heated debate in Central Europe on the invasiveness of alien trees, including species like Tree of heaven (Ailanthus altissima), Black cherry (Prunus serotina), Boxelder (Acer negundo), Northern red oak (Quercus rubra) and Black locust (Robinia pseudoaccacia). The discussion includes conservationists on the one hand, who argue that alien species are causing impacts on native ecosystems, and that they should not be cultivated. On the other hand, foresters make the point that these species are crucial for the economy, and that the impacts described by conservationists are not accurately addressed, and exaggerated.