FLORISTIC CLASSIFICATION OF THE FLOODPLAIN ALDER, WILLOW AND POPLAR FORESTS IN THE BASIN OF THE LOWER SULA (UKRAINE)

Abstract

The floodplain alder (Alnus glutinosa), willow (Salix alba, rarely S. fragilis) and poplar (Populus nigra, P. alba, outliers of Populus x canescens) forests in the basin of the lower Sula were investigated. Mesohygrophilous forests of European black alder were referred to Alno-Ulmion alliance Querco-Fagetea class (com. Aegopodium podagraria-Alnus glutinosa, D. c. Acer negundoAlnus glutinosa). Swamp forests of European black alder of Alnetea class are mostly common in the floodplains of small rivers and are represented by two associations (Carici ripariae-Alnetum glutinosae and Carici acutiformis-Alnetum glutinosae). The floodplain willow and poplar forests were referred to class Populetea albae (order Populetalia albae). Willow forests of floodplains of the river Sula and its tributaries and also waterlogged gully talwegs and rarely outliers belong to Salicion albae alliance and Salicetum albae association. Lower reach poplar forests of the river Sula floodplain belong to Calamagrostio epigei-Populion nigrae alliance and are divided into two associations that we propose to change in accordance with the requirements of the International Сode of Phytosociological Nomenclature for Galio veri-Populetum nigrae and Strophiostomo sparsiflorae-Populetum albae. It is emphasized that the studied groups don't contain the species from the Red Data Book of Ukraine. The alder, willow and poplar forests of each association that are least transformed, largest in area and oldest require the nature reserve creation, that is proved by their significant water conservation role.