Scientific publications

Received 19.10.2017 The studies were carried out in Eastern Fennoscandia, a domain embracing the Kola Peninsula, Karelia, a part of the Leningrad Region and the eastern Finland, and noted for a prevalence of pine forests due to a wide distribution of poor sandy soils. The paper discusses the coenotic diversity on automorphic sandy soils, where the authors distinguish three types of forest growth conditions with their respective primary communities: bilberry pine forest (P. s.-V. m.), cowberry pine forest (P. s.-V. v.-i.), lichen pine forest (P. s.-Cl.). The typology is built upon the differences of the ecological conditions (the principal features taken into account are groundwater bedding depth and soil texture) as well as dynamics (orderly changes in the composition and structure of communities at different stages of reforestation after catastrophic disturbances). Plant associations forming dynamic series were identified for each stage of the forest regeneration. The scope of the associations generally conforms to the principles formulated by the 1910 Botanical Congress: equal consideration is given to habitat properties, species composition of the communities and their physiognomy as expressed in the composition and structure of the tree layer which, in its turn, largely defines the structure of the entire community. Overall, the diversity of communities on automorphic sandy soils at the clear-cut stage is limited to 3-4 associations. In the sites with lichen- and cowberry-type conditions the communities then develop without a change of species, and in bilberry-type conditions there will be a high proportion of deciduous species (Betula sp., less often Populus tremula). The dynamic series usually converge as early as at the stage of middle-aged communities (50-100 yrs). Starting from there, the species composition in lichen- and cowberry-type conditions does not change, although some alterations happen in the ground cover structure in connection with the state of the tree layer. In bilberry-type conditions the series with early stages dominated by the feather reed grass joins the «central» series only after 100 or more years. The studies have demonstrated that it is not only necessary but also possible to create a fairly easy-to-use typology for forestry purposes, which comprehensively represents the coenotic diversity of the territory and the vegetation dynamics. The array of types for a specific area (forest district) will be quite small if the associations are determined by three major indicators: species composition of the community, habitat conditions, and characteristics of the tree layer.