Features of Radial Growth of Trees in Shelterbelts of the Dry Steppe

Abstract

Dendrochronological and dendroclimatic analyses of radial growth of trees in shelterbelts of the dry-steppe subzone are presented. In dry steppe conditions, trees of shelterbelts are very sensitive to climate change and are forced to adapt to extreme conditions, which directly affects their annual increment. The radial growth of trees and their response to climatic factors are determined by their species composition and geographical location within the dry steppe. The rates of radial growth vary significantly among species. Poplars show the highest increment. Larch chronologies are characterized by the lowest rates of radial growth. Birch chronologies are the most sensitive to climatic fluctuations, and pine chronologies are the least sensitive. A statistically significant relationship with precipitation, temperature, area moisture index (with the Selyaninov hydrothermal coefficient), and the Palmer Drought Severity Index (sc-PDSI) is noted. A deficiency of precipitation and increased air temperature most often cause a decrease in the wood increment. A large number of narrow, wedging, and missing reference rings were noted. The analysis of the age structure of the studied trees of shelterbelts showed that they are moving into the senile stage of development. Further increase in climate aridization will inevitably affect the growth of trees of shelterbelts and create additional risks for their existence.