Broadleaved forests of the Oka-Don plain within the borders of Penza region

Background. The Oka-Don Plain is located in the north-west of Penza region. The vegetation of the territory is represented mainly by forests: secondary forests predominate, deciduous forests with a high proportion of pedunculate oak make up about 10%. Materials and methods. The composition and structure of broad-leaved forests was studied during route and stationary studies on sample plots. The analysis included 121 complete geobotanical descriptions within the natural contours of plant communities using generally accepted methods, indicating the percentage of projective plant cover. Vegetation classification was carried out from ecological and cenotic positions. The ordination of geobotanical descriptions was carried out using the method of indirect gradient analysis (DCA) using the PC-ORD5 package. The structural diversity of communities was assessed by the ratio of ecological-cenotic groups (ECG) species in the composition of the vegetation cover. We assessed the successional state of communities. Results and conclusions. Broad-leaved forests are not widespread on the Oka-Don Plain within the boundaries of the Penza region and are confined to weakly undulating interfluve spaces composed of thin fluvioglacial deposits. In the grass cover of broad-leaved forests, in terms of number and species abundance, nemoral species are the absolute dominants. The absolute dominant of broad-leaved nemoral forests is Carex pilosa. Boreal-nemoral forests are characterized by a dense canopy of Corylus avellana. As a result of economic activities, forests with a high participation of meadow species were formed. All modern forest cenoses are at different stages of demutation after logging of varying degrees of intensity, grazing, fires, and plowing.