ASPEN FORESTS OF THE LOW PLATEAU OF THE VOLGA UPLANDS

Modern forest vegetation of the low plateau of the Volga Upland is represented by pine, birch, aspen, black alder and broad-leaved (mainly oak) forests. The article is devoted to the analysis of the current state of aspen forests in the landscapes of secondary moraine plains. The study of the composition and structure of aspen forests was carried out during route and stationary studies on trial plots. The analysis included 152 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 using the PC-ORD5 package. The structural diversity of communities was assessed by the ratio of ecological-cenotic groups species in the composition of the vegetation cover. We assessed the successional state of communities. Aspen forests are not widespread in the forest-steppe landscapes of the low plateau of the Volga Upland and occupy about 23% of the forest area. In the grass cover of aspen forests, in terms of number and species abundance, the absolute dominant species are nemoral species, with nitrophilous species occupying second place. Aspen forests are represented by 6 associations. The most widespread communities are dominated by Carex pilosa. Aspen forests are characterized by 8 highly constant species, exclusively nemoral ecological-cenotic group. Aegopodium podagraria is most often found in the communities of the low plateau of the Volga Upland. An assessment of the successional state of aspen forests showed that they are distinguished by a high participation of nemoral species among both tree forms and grasses. Absolute dominance in the tree layer belongs to exploratory (R-species) species. The origin of aspen forests is associated with non-moral grass broad-leaved forests, on the site of which they arose after repeated felling and grazing