THE ASSOCIATION OF SPREADING ELM AND NARROW-LEAVED ASH (FRAXINO-ULMETUM LAEVIS SLAV. 1952) IN FLOODPLAIN FORESTS OF THE PODRAVINA AND PODUNAVLJE

Abstract

The association Fraxino-Ulmetum laevis is a forest community of hard broadleaves occupying the highest positions in floodplain areas along large rivers of south-eastern Europe. It was described for the first time in Vojvodina by Slavnić in 1952. According to earlier research, this community is developed in Baranja in Croatia, then downstream of the river Danube up to Ilok, fragmentarily in the area of the Podravska Slatina forests, and along the river Sava in the Spačva area. The results of synecological-vegetation research indicated the existence of this community over entire Podravina and Podunavlje, mostly on sandy alluvium and on the eugley hypogley soil type. The floral composition of the association Fraxino-Ulmetum is shown on the basis of 19 relatively heterogeneous phytocoenological relevés from the Podravina and Podunavlje. The results of multivariate analysis and the results obtained by classical synthetic analysis of these relevés revealed the existence of two variants. The first, drier, is linked to the river Drava and the upper and central part of its course. It is labelled as the variant Prunus padus. The second, more humid, is linked to the Danube, and is labelled as the variant typicum. Within the latter, there are certain differences between the relevés from Baranja and those from the Danube islands in eastern Croatia, which are the result of different hydrological-pedological conditions. The forest of spreading elm and narrow-leaved ash was formerly relatively well represented, albeit fragmentarily and over small areas. Today, it is expanding again because drier conditions, infrequent and shorter-lasting floods favour its development. The community does not have any significant commercial value, but from the aspect of biological diversity, ecological stability and general benefits it is highly valuable and should be preserved wherever possible.