Ecological Systems and Devices Annotation << Back Simulation the Variability of Pine Growth in Biogroups With Differ-Ent Structure Maksimova O.V., Koukhta A.E. The study of the variability of forest ecosystems responses to the biotic and abiotic environmental factors infl uence is an important tool for assessing climate change. The literature has covered the population variability of tree stands based on generalized material from phytoassociations characteristic of different habitats. However, due to the growing conditions heterogeneity in forest ecosystems, trees biogroups are formed during the growth process, which compound integral cells of the tree stand. The cluster trees distribution in phytocenoses serves as a characteristic condition for the forest ecosystems formation. For a better understanding of the biocenoses functioning, the structure of clusters – biogroups – should be analyzed. The work aime was to identify the influence of structural characteristics of Scots pine Pinus sylvestris L. biogroups on the rate of height increments variability stabilization. A model based on Markov chains was constructed, reflecting the resource exchange dynamics in a biogroup. The conducted modeling made it possible to obtain reliable conclusions. Its necessity is justified by the complexity of empirical fi eld studies, in which the ecological states dynamics operating at any level of the hierarchy can often be unobservable or “hidden”. The variation coefficients vector, which smooths out the tree age, was selected as the output parameter for tracking the dynamics. It was found that within biogroups linear increments variability stabilization occurs regardless of the structural characteristics of the micropopulation itself. However, the stabilization rate depends on the forest stand clusters structure. The following structural characteristics were considered: the number of overdominants in a biogroup and its homogeneity in terms of the diversity of dominance classes. In particular, it was found that an increase in the number of overdominants slows down the stabilizing variability process, and the biogroup heterogeneity accelerates the process of stabilizing variability only in the case of the presence of only one overdominant. The results of the constructed model verification on a sample of data from 42 pine biogroups of the Central Forest State Nature Biosphere Reserve are presented. The work conclusions will help to optimize the tools for boreal ecosystems environmental monitoring in the context of recorded climate change and anthropogenic pollution. Keywords. Forest ecosystems, biogroup, Markov chains, stabilization, variability. DOI: 10.25791/esip.3.2025.1509 Pp. 20-32.