Structure of Undergrowth of Spruce in Different Phenological Forms on Height Depending on the Composition and Structure of Forest Stand

Abstract

The article deals with the interrelation of forest canopy of trees and high-rise structures of spruce undergrowth of different phenological forms in pleurocarpous moss group of forest type in conditions of Leningrad region. The analysis of high-rise structures of different phenological forms depending on the composition and structure of forest in the most represented types of forests in Leningrad region is made. For further insights on the role of composition and structure of forest stand as factors determining high-rise structure of different phenological forms of undergrowth of spruce, analysis of variance was conducted. Decrease in the share of large height spruce undergrowth of all phenological forms in the increase of participation of spruce in the growing stock, with increasing elative completeness of forest stand, its age and stock, allowed to conclude that the structure of natural regeneration of spruce on height is affected by the degree of illumination under the canopy of forest stand. Analysis of altitudinal structure of spruce undergrowth in different phenological forms in height, depending on forest type showed that proportion of the undergrowth of all phenological forms is higher in dry forest types than in wet forest. From this we can conclude that high-rise structure of spruce undergrowth in different phenological forms is influenced not only by illuminance under the canopy of the forest, but also fertility of soil, its physical and chemical properties. Conducted analysis of variance confirmed statistically significant dependence of this factor. As a result of conducted research it can be concluded, that in conditions of middle taiga of all biocenotic factors factors, forest type and composition of stands have greater influence on high-rise structure of phenological forms of spruce undergrowth.