Dynamics of the height of Siberian spruce in the stands of the Yenisei Ridge

Background. The height of trees is an essential indicator in forest inventory, closely associated with stand productivity. It is a widely utilized metric for characterizing site conditions, both within individual forests and for comparing stand development across diverse climatic zones. The relationship between tree height and diameter is a pivotal aspect of forest stand vertical structure, ultimately informing the development of primary inventory standards for the commodity structure. Purpose. The objective of this study is to identify the characteristics of height change in Siberian spruce trees in mature stands of the Yenisei Ridge, a mountain taiga region with challenging conditions for woody vegetation growth. Materials and Methods. The study was conducted in mature stands of Siberian spruce (Picea obovata Ledeb.) on the Yenisei Ridge, a mountain range in the western part of the Central Siberian Plateau. The research was based on data obtained from 15 research plots placed in stands with a predominance of Siberian spruce in the stand composition, as determined by the largest growing stock value. Results. In the course of mathematical analysis, a number of series of natural development of forest stands were identified, both within a group of forest types and even within a single forest type. The findings of the study indicate that the application of the bonitet classes scale in the formulation of inventory standards for spruce stands is unwarranted, given that the bonitet scale encompasses the absence of growth in height in stands of considerable age. The growth intensity of spruce stands in height can be delineated into three phases, each characterized by a distinct variability of the complex assessment indicator. Conclusion. The findings of this research indicate that mature, low-productivity spruce stands subjected to the harsh climatic conditions of the Yenisei Ridge exhibit a number of characteristics associated with tree growth in height. The utilization of a bonitet scale for the establishment of inventory standards for spruce stands is not a viable proposition. This is due to the fact that the bonitet scale incorporates the absence of height increments in stands of considerable age. Consequently, in order to ensure the suitability of the regulatory forest inventory base for spruce stands on the Yenisei Ridge, it is essential to develop a bespoke approach that takes into account the specific site conditions.