Coevolution of soils and vegetation in the southern taiga (with the Prioksko-Terrasnyi reserve as an example)

A detailed characterization of the relief, parent materials, soils, woody vegetation, and the links between them is given for a small part of the southern taiga zone in the center of the East European Plain. A methodology for determining the vegetation succession patterns on different soils with the use of the selectivity coefficient K is suggested. This coefficient is defined as the ratio between the frequency of occurrence of the given tree species on a given soil and its average frequency of occurrence within the entire analyzed area (in the area of the reserve). The values of K change from 0.2 to 3.6 and indicate positive (K > 1) and negative (K < 1) feedback relationships between the soils and vegetation. Changes in the frequencies of occurrence of different tree species on different soils that took place over 19 years have also been studied. It is shown that spruce has a tendency for settling on podzols, mixed spruce-oak-lime forests tend to develop on podzolized podburs, and lime and oak trees tend to develop on soddy podburs. Birch stands are most often replaced by spruce and pine stands; aspen stands and a part of the birch stands are replaced by lime and oak stands. The ecological plasticity of pine trees and the long age of this tree species ensure the existence of a long transitional succession stage with the predominance of pine. These regularities are important for predicting the further development of forest vegetation.