SPECIFICITIES OF THE DISTRIBUTION OF THE BIRCH-PINE STANDS OF WESTERN POLISSІA BY YIELD CLASSES

Abstract

In this article we have analyzed the silvicultural and taxation features of the distribution of birch-pine stands in Western Polissіa by yield classes. The determined distribution of the share of pine stock in mixed stands of Western Polissіa allowed to identify a decrease in its value in birch-pine stands in the 7th–10th deciles with an increase in yield classes. At the same time, it has been noted that there is an opposite process of increasing the share of pine stock in the analyzed stands in the 1–6th deciles with a decrease in yield classes. The established distribution of pine stocks in stands allows us to identify candidates for removal when planning thinning. It has been established that the distribution of the birch stock share in mixed birch-pine stands of the analyzed region depending on the yield classes is characterized by a similar trend. In particular, the increase in the share of birch stock in the 1–6th deciles ranges from 0.7 to 1.4% and is characterized by the highest rate in stands of Ia and I yield classes. A significant and high negative correlation is shown between the proportion of birch stock in the 1st–6th deciles of mixed stands according to their yield class. In the 9th and 10th deciles, there is a direct low and high correlation between the share of birch stock according to the mixed stand yield classes. The investigations made it possible to note the presence of a medium and strong (from 0.30 to 0.96) correlation between the proportion of the stock of the elementary part of the stand and its potential productivity.