Peculiarities of net forests primary production formation in different site conditions of the Carpathian National Nature Park

Forest plant communities of the Earth are one of the grounding factors influencing the global carbon cycle in the context of global climate change, as they are not only a source of carbon emissions from autotrophic respiration and oxidation of organic matter but also provide its intensive sequestration from the atmosphere in the course of photosynthesis. The natural dimension of this process is the net primary production of forest ecosystems. The research object is the features of the bioproduction process in forest plant communities of the Ukrainian Carpathians. The subject of research is the peculiarities of net forests primary production formation in different site conditions of the Carpathian National Nature Park. The purpose of the research is to carry out a comprehensive quantitative assessment of net primary production and features of the intensity of organic matter production by forest plant communities in different types of forest site condition. The assessment based on the application of the «semi-empirical» method, which considers the ecosystem net primary production of a certain age as an analogy to the current annual increment in total live biomass production. The basis for the assessment is comprised of stand-level characteristics of forests and mathematical tools based on data collected at 80 temporary sample plots. The forests of the Carpathian National Nature Park produce annually almost 360 thousand tons of plant organic matter. At the same time, the average density of net primary production of the studied stands is more than 1000 g·(m2)-1·year-1. Spruce stands produce almost 75 % of the production of forest plant communities of the park. The peculiarities of forests’ primary production formation in the stands of different forest site conditions are determined. In particular, more than 70 % of the production is accounted for stands in moist fertile hornbeam site type, 80 % of which produced by mid-aged stands. A significant influence of the type of forest site conditions and stand productivity on the indices of organic matter production intensity by the forest stands of the park are established. The highest values of this index are inherent for stands with Ib and higher site index classes in moist fertile hornbeam site type which are at the level of 1300 g·(m2)-1·year-1. At the same time, beech stands in these forest conditions reach values of more than 1700 g·(m2)-1·year-1. Almost 55 % of the primary production of the studied forests accounts for stem wood (26.8%) and photosynthetic apparatus (27.1%). At the same time, a significant impact of the changes in forest site conditions types on the studied index fractional structure was estimated. The research results on the primary production of the Carpathian NNP forests form an information basis for forecasting their role in biosphere.