The climatic signal in tree rings of the common oak (<i>Quercus robur</i> L.) on the south-eastern border of its range in the Ural River basin, Russia

Abstract

Aim. The objective of this study was to identify and analyze the climatic signal contained in the tree-rings of common oak on the southeastern border of its range in Russia (Ural River basin).Material and Methods. The materials for the study were tree-rings in samples of common oak wood from three sites in the southern part of the Dziau-tyube ridge. Measurements of ring-width were performed on the MBS binocular microscope and on the Lintab measuring complex with the TSAP-WinTM software package. The construction of tree-ring chronologies was carried out in the ARSTAN program. Dendroclimatic analysis was carried out in the R package treeclim.Results. The limiting climatic factors for the radial growth of the common oak on the southeastern border of its range are precipitation during the winter-spring season and the initial period of vegetation and to the greatest extent with the precipitation in March-May. It was shown that the strength of this climatic signal in oak tree rings was not constant over time. The dynamics of this signal are characterized by the presence of local periods of decline, the beginning of which is timed to the years of mass gypsy moth outbreaks.Conclusions. Since the beginning of the 1980s, there has been a significant decrease in the relationship of radial growth with the amount of precipitation for March-May. The reason for this change, in our opinion, could be a strong change in the condition of trees and stands caused by the consistent impact of strong oak defoliation caused by Gypsy moths and late spring frosts.