Tree-Ring Variability of Larch (Larix Sibirica Ledeb.) in Different Landscape Positions of the Terekhol Depression, Tuva, Russia in the 20th Century

Abstract

Dendroecological approach was applied to study of fundamental problem in landscape science - a relationship between pattern and functioning of landscape. Using the tree-ring width of larch (Larix sibirica Ledeb.) in different environmental conditions we analyzed the transformation of regional (climatic) factors by landscape pattern heterogeneity. The study area is south-western part of Terekhol Depression in Tuva region, Russia. The considered time period is 1906-2008. It was found that the dynamics of tree-ring growth depends on external factors (62%) rather internal ones (38%). Major components of radial growth variability were identified and their interpretation was discussed. The contribution of each component to growth variability of trees was calculated in various sites. The results show that the main factor of variability is the regional dynamic of meteorological parameters transformed into spatially heterogeneous landscape. The factor of summer precipitation (June-July) of current and last growth season is especially significant for the forest-steppe plant communities. The autonomous taiga ecosystems of watershed without permafrost and superaqueous taiga ecosystems on Cryosol at the bottom of small stream are sensitive to precipitation and temperature regime. Boreal forest communities on the north slopes of Terekhol Depression are not susceptible to moisture regime. The dynamic of larch tree-ring growth on the lake terraces related to the groundwater depth, depending on the lake level.

Keywords

• dendroecology
• tree-ring growth
• Siberian larch
• local conditions
• landscape heterogeneity
• climate
• Tuva