Spatial organization of the main park-forming species in landscapes of the «Оlexandria» state dendrological park of the National Academy of Sciences of Ukraine

The article presents the research results of spatial structure of the main park-forming species (Acer platanoides L., A. campestre L., Fraxinus excelsior L., Tilia cordata Mill.) in the ecotopes of the «Оlexandria» State Dendrological Park of the National Academy of Science of Ukraine are presented. The spatial structure was determined by mapping trees by age groups. The spatial organization of the studied tree species has species specificity and shows age confinement to different park ecotopes. The most numerous Acer platanoides and A. sampestre are distributed more or less evenly throughout the park. The third most abundant species, Fraxinus excelsior, is concentrated in the eastern part of the park. The formation of a large young cenopopulation in the south-western part of the park was noted. The predominant number of natural stands of Tilia cordata is concentrated in the oak woodlands of the western part of the park. Today the population of Tilia cordata is practically not recovered, however, over the past half of a century it has formed a powerful ecotone in the oak forest in the central part of the park, displacing the species-edifier Quercus robur L. Populations of all studied species have a full age structure in oak-oak-type plots. The age structure of all species is disturbed in technogenically polluted ecotopes, in areas of mass phytopathogens reproduction in quasi-natural areas with significant anthropogenic interference. The distribution of older age groups individuals is mostly random and uniform, while group distribution is observed in younger trees. In all studied species more dense areas of all ages’ specimens or sparse, small groups or even single specimens, are distinguished. The latter is typical for older age groups trees. The main factors determining the distribution of the main park-forming species are the ability of tree species natural regeneration, pest and disease damage, and economic activity. Key words: forest type plantations, spatial structure, tree mapping, age groups, types of spatial distribution, factors determining distribution.