ESTIMATION OF RANK POSITION OF TREES IN STAND PHYTOMASS RESEARCH
When constructing standards for aboveground phytomass of trees, the use of traditional methods of forest taxation science, developed to determine the volume of tree trunks and in which only their linear dimensions (diameter and height) are used as the main volume-forming indicators, is not entirely correct. In particular, the phytomass of the crowns depends not only on the size of the trees, but also on their development and rank position in the tree stand. As a result of the conducted studies, it was found that the rank of trees of the same thickness and their position in the canopy vary depending on the conditions of the growing area (forest types), age and density of stands. In the ontogenesis of stands, there are ecological, age, and density shifts in the ranks of trees of the same diameter. The variability of the mass of crowns, and, consequently, their structural parts (branches, needles and generative organs) is correctly associated with the height and diameter of trees, only in stands of the same type of forest with insignificant age heterogeneity of trees. The assessment of the variability and features of the accumulation of crown phytomass within the natural age series of growth and development of stands (in stands of different ages growing in homogeneous forest growing conditions) is correctly carried out taking into account the age, diameter and height of trees. In such studies, covering a variety of natural development series, there is a need to use an additional indicator that characterizes the quality of the growing conditions - the class bonitet. The rank position, size and phytomass of the crown, as well as the ratio of branches and needles in the crown of trees of the same thickness vary depending on the density, age and conditions of the growing area of the stands.