Taxation and forestry features of the growth and development of plantations of shrub birch under conditions of the Central Siberian plano-mountain-taiga region

Abstract

Shrub birch or Yernik (Betulafruticosa) grows along river valleys in excessively waterlogged areas. Scientific interest in this plant is due to the lack of information on taxation patterns of vegetation and growth of this plant in Siberia. Shrub birch growing in the Baikit region, the territory of the Central Siberian Plateau is the object of the study. Based on the taxation data of the forest inventory of the Baikitsky forestry, 95 sections with the growth of birch shrub were selected. All plots were characterized by a clean composition. The quality of the growing conditions is Vа bonitet class. A birch forest up to 10 years old was characterized by a meadowsweet-ledum forest type, a sedge-sphagnum type was observed in birch forests of 15–20 years old and a rosemary-sphagnum forest type is characteristic of 30 years old birch forests. Yerniki of meadowsweet-ledum forest type had a density of 0.4–0.5. The birch forest of the sedge- sphagnum type was characterized by a wide variety of density (0.5–1.0) with a predominance of high-density thickets. Shrub of rosemary-sphagnum type develops in fullness of 0.4–0.5. On the basis of empirical formulas, a tabular form of indicators of heights and diameters, as well as the values of growth by age of shrub birch in the conditions of the Central Siberian Plateau, was obtained. It can be stated that the conditions of the place of growth determine the longevity and dimensional parameters of Shrub birch. The maximum parameters of Shrub birch characterize the critical conditions for the existence of a woody plant: age – 30 years; height – 5 m; diameter – 4 cm: fullness – 1.0. The current growth of Shrub birch in height and diameter exceeds the average growth, which indicates a steady growth of shrub birch in the study area. The absence of older age groups of birch forests is due to the processes of changing climatic conditions (permafrost thawing), which causes the death of thickets.

The age, typological and size structure of shrub birch forests depends largely on the habitat conditions and climatic characteristics of the territory.