Analysis of the Tree Ring Chronology Network at the Upper Timberline in the Southern Siberian Mountains

Within the last decade, significant progress has been made in researching the upper timberline of the Southern Siberian mountains. For this end, a network of millennial tree-ring chronologies has been compiled. The aim of this study is to analyse a set of quantitative (tree ring width, latewood optical density) and qualitative (frost damage, light and missing rings, density fluctuations) growth parameters for larch trees growing on 12 sample plots within this network. The tree ring width analysis revealed that the analysed tree ring chronologies network is divided into two large clusters (western and eastern), within which the chronologies are in good agreement with each other over a distance of 500 km), allowing the construction of two regional chronologies. The results obtained indicate the need for further work to integrate materials from different millennial chronologies within a cluster, and to subsequently develop regional chronologies. An analysis of the anatomical structure of tree rings revealed five extreme events that occurred throughout the study area (1884, 1869, 1854, 1813, and 1783) and reflect regional scale climatic anomalies. Methodologically, the study demonstrated that at the upper limit, there is no fundamental difference in the choice of method for measuring tree ring width (analog or digital), and the use of a parameter such as latewood optical density circumvents limitations associated with local variability in growth.