The alliance Alnion incanae includes broad-leaved floodplain forests with Alnus incana in the mountains, Alnus glutinosa and Fraxinus excelsior at mid-altitudes, and the former two species together with Quercus robur, Ulmus laevis and U. minor in the broad floodplains of lowland rivers. In southern Moravia Fraxinus angustifolia can be added to this assemblage, occuring in lowland floodplain forests. Soils of these forests are usually flooded in spring for several days or weeks, but the water table recedes later in the growing season. These soils are rich in nutrients and productive.