Feshchenko R. Ecosystem functions of forest stands of the parkmonument of landscape art “Feofania”

The dissertation is devoted to the assessment of ecosystem functions of forest stands of the park-monument of landscape gardening art “Feofania”. The methodological basis of ground and remote measurements is formed on the principles of integrated forest stand accounting using classical methods of forest mensuration, assessment of the current increment of ecosystem functions, namely carbon sequestration, growth of live biomass, formation of dead biomass, current sequestration of carbon, oxygen production and energy accumulation. The manuscript of the dissertation substantiates the main issue of the state of forest stands, their ecological functions in the context of solving the issues of global climate change. The study of the main ecosystem functions of forest ecosystems that prevent the globalization of climate change and the search for ways to reduce emerging environmental risks is one of the priority research areas. During the fulfillment of the tasks of the dissertation research, a number of generally accepted and standardized methods in forest mensuration were applied to study the state of forest stands of the park-monument “Feofania”. The field research was carried out in space and time on the territory of permanent sample plots, which were established in 2016-2017 within the park-monument of landscape gardening art of national importance “Feofania”. According to the species composition, the research object is formed of Common oak (QURO), Common hornbeam (CABE), Sycamore maple (ACPL), Small-leaved linden (TICO), European white elm (ULLE), Black locust (ROPS), Common ash (FREX). The biophysical indicators of ecosystem functions were assessed using classical forest mensuration formulas and forest mensuration reference books for the assessment of aboveground live biomass components of trees of the main forest-forming species of Ukraine. The research revealed a general increase in the reserve of stored carbon in the biomass of stands, as well as multivector dynamics of the structure of stored carbon in the live biomass and tree woody debris, which can potentially negatively affect the ecosystem functions of the park's forest stands. The research results confirmed a decrease in the carbon sequestration potential of stands under conditions of more intensive decline and lower current increase of stand live biomass. A positive, from the ecological point of view, tendency to increase the share of coarse woody debris (dead biomass) in the biomass structure of the experimental stands was established. The increase in the stock of dead biomass creates prerequisites for maintaining an environment for biodiversity. The species composition of the experimental stands on the permanent sample plots is mainly represented by Common hornbeam (on plots 2 and 3) and Sycamore maple (on plots 1 and 4). The number of trees of Common oak, Small-leaved linden, European White elm, Black locust and Common ash in the experimental plots is less numerous. It was found that the structure of the live biomass of the surveyed test plots was mainly formed by the stands of Common oak, the share of which, during the study period, was No. 1: 70-67 %; No. 2: 56-55 %; No. 4: 82-81 %. During the establishment of the sample plots, dry trees were mainly recorded in oak and hornbeam stands. Studies have confirmed an increase in the percentage of snags formed during the accounting period. It was found that middle-aged (~80 years old) stands of Common oak can reach similar structural heterogeneity as older (>150 years old) forest ecosystems. Successful natural regeneration, the formation of a layer of undergrowth and the formation of a microhabitat are highly dependent on spatial and non-spatial forest attributes. The largest increase in live biomass is accounted for by the stands of Common oak in the three sample plots, the growth of which was most intense in the first sample plot, which amounted to 71.3% during the study period. The processes of dead biomass formation in the studied plots had positive dynamics of its formation, which is directly related to the processes of deadwood and dryness formation. The largest share of dead biomass formation is represented by Common oak and hornbeam. Studies have shown a decrease in the carbon sequestration potential of stands under conditions of more intensive decline and a decrease in the current growth of live biomass of stands. The increase in indicators of ecosystem functions, namely, growth of live biomass, carbon sequestration, oxygen and energy productivity, had different intensities by tree stand components. The predominant share, more than 60%, is accounted for by the trunk in the bark of the trees that form the forest stands of the study object. By species, the most intensive processes of formation of ecosystem function indicators were observed in the Common oak, and the reduction of the park area significantly reduces their level over a long period.