Khan Y. Dynamics and Forecast of Growth of Common Oak Coppice Stands in Ukrainian Forest-Steppe

The dissertation is devoted to studying growth of common oak stands of vegetative origin in Right Bank and Left Bank Forest-Steppe of Ukraine, and actualizing biometric indicators that characterize their productivity and forecast growth. The relevance of the research is linked with the important role that oak stands of vegetative origin play in the natural formation of Forest-Steppe ecosystems of Ukraine. These stands have a significant area (about 26 % of the total area of all oak stands in the research region). Therefore, questions of the development of models for updating biometric indices of such stands are of high importance. For experimental research, information from the stand level database of IA «Ukrderzhlisproekt» was used, which characterizes pure and mixed common oak stands of vegetative and seed origin (as of 01.01.2011). Also, as experimental data for mathematical modelling, the results of processing materials obtained on temporary sample plots were used, which representatively reflect the main biometric indices and the most typical growth conditions of coppice oak stands. As a result of the research, mathematical models of dynamics of such biometric indices as average height, average diameter, form factor and stock per 1 ha for modal usual oak stands of vegetative origin in Forest-Steppe of Ukraine are proposed. The obtained mathematical dependences are characterized by a sufficient level of accuracy in the description of the initial data and are used to develop appropriate yield tables. To study the growth forecast, the main biometric indices, such as average height, average diameter, stand basal area and growing stock per 1 ha, were subject to mathematical processing and modelling. The main parameters of mathematical models for the forecast of biometric indices were set using the nonlinear regression function of the statistical software package IBM SPSS Statistics. The obtained results were compared using the graphic-analytical method. As a result of modelling, equations have been obtained, which with sufficient accuracy describe the studied ratios and predict growth by the main biometric indices at different age intervals. As a result of the dissertation research, the following tools are proposed for use in forestry and forest management planning enterprises – dynamic site index scales, yield tables for modal stands and mathematical models for actualizing the database «Forest Fund of Ukraine» for coppice mixed common oak stands in Forest-Steppe zone of Ukraine.