Steepness and types of steepness of structure curves according to volume of aggregates of forest stands of different categories and tree species

Based on data on the structures according to volumes of aggregates of forest stands of different categories – seed-tree coniferous and deciduous, rapidly growing, coppice, and forest plantations, the steepness of the structure curves has been studied while using the new index method for comparing parabolic curves (Petrin, 2021) , and the types of steepness have been determined by a new method – the method of coefficients, and, for comparison, by the method of natural indicators (Douhovnikov, 1966). Comparisons between the coefficients according to types of steepness and the zero natural indicators have showed an inversely proportional relationship with a high degree of correlation. The curves of the structure indices according to volumes of the particular aggregates of the studied stands according to tree species and stand categories have been compared, and the values   of the obtained indices have been analysed. By applying the new coefficients for the types of structure, the values   and ranges of the steepness indices of all structure curves according to aggregates of stands have been found. It is concluded that the coefficients for the types of structure, as well as the indices according to steepness, are quite convenient tools for finding the differences in the structures of forest stands and homogeneous aggregates of these.