Sigmoid functions in modeling Scots pine growth course in height

The results of the analysis and applicability of sigmoid functions for studying the Scots pine crops growth on the territory of the North taiga region of the European part of the Russian Federation in the blueberry type growing conditions are presented. A computational procedure for finding models of forest crop growth progress is proposed. The growth progress model reflects the relationship between age and height of a tree and contains sigmoidal growth progress functions in its description. Sigmoid functions were selected for each of the five growth phases and development of the stand as a result of regression analysis. In general, the model of the Scots pine crops growth course in bilberry forests of the northern taiga region of the European part of the Russian Federation represents a system of equations based on the Weibull, Drakin-Vuevskii and Richards equations.