Euonymo nanae-Quercetum roboris Pînzaru, Sfeclă & Cantemir – ass. nova in the Republic of Moldova

This article describes the mesohygrophilous (mesophilous) forests of Quercus robur L. with Euonymus nanus M.Bieb., occurring in the floodplains of small rivers within the intercolline valleys of the Central Moldavian Plateau and the Dniester Plateau. The phytocoenological investigations of the studied communities were conducted using the Braun-Blanquet methodology. The tree layer is dominated by Quercus robur, represented mainly by centuries-old individuals, while other accompanying species occur only sporadically. Carpinus betulus generally appears infrequently in the second sublayer; however, in sectors located further from the river, under anthropogenic influence, Quercus robur has been replaced by Carpinus betulus L., communities that may be included at the facies level (carpinosum betuli). The floristic and ecological analysis of these phytocoenoses in the Republic of Moldova suggests that the association Euonymo nanae-Carpinetum (Borza 1937) Seghedin et al. 1977, previously reported by other authors, should not be recognized and instead be grouped into a new association. Based on 23 phytocoenological relevés conducted by the authors, a new association is proposed for science – Euonymo nanae-Quercetum roboris Pînzaru, Sfeclă & Cantemir, included within the alliance Fraxino-Quercion roboris Passarge 1968, the order Alno-Fraxinetalia excelsioris Passarge 1968, and the class Querco-Fagetea sylvaticae Br.-Bl. et Vlieger in Vlieger 1937.