Silvicultural Characteristics of European Larch Trees of Different Kraft Classes in Forest Crops

A comparative study of silvicultural characteristics of the growth of trees of various Kraft classes has been conducted in the forest crops of European larch (Larix decidua Mill.) growing in the centre of the Russian Plain in the conditions of a blueberry pine forest (Pinetum myrtillosum). The relevance of the work is due to the absence of similar studies for artificial dendrocenoses over the past 25 years. The dynamics of reduction numbers, soil-light increments and relative heights of trees of different Kraft classes at the maturity stage of the stand (124–149 years old) has been considered. It has been established that at the age of 124, 134 and 149 years old, reduction numbers and relative heights are strictly differentiated in terms of different Kraft classes and this feature has been maintained for 25 years. Moreover, from 124 to 149 years of age, the reduction numbers and relative heights for different Kraft classes change little, and for trees of Kraft classes I and II they are almost stable. Trees of Kraft class III are closest to the average diameter and average height of the entire stand: they differ by 7 % in diameter and by 2 % in height. The silvicultural peculiarity of trees of different Kraft classes is not only the specificity of their rank position, but also the nature of the functional implementation of soil-light increments, both in diameter and in height, in different periods of time. For example, in the time period of 124–134 years of age, the soil-light increment in diameter of trees of Kraft class V has been 3.3 times less than in class I, and in height – 3.9 times less. In the period of 141–149 years of age, the difference in soil-light increment in height has not changed, but in diameter it has increased to 4.3 times. In dynamics, the values of soil-light increment and relative height show a depression of growth processes in trees of Kraft classes V, which become candidates for mortality. In general, the division of the plantation into Kraft classes reflects the functional hierarchy and shows the existence of rank structures of the dendrocenosis and their stability over time.