The influence of soil hydrothermal regime of larch growth in Central Yakutia
2007
Fedorov, P.P. | Desyatkin, A.V., Russian Academy of Sciences. Siberian Branch, Yakutsk (Russian Federation). Institute of Biological Problems of Cryolithozone | Nikolaev, A.N., Russian Academy of Sciences. Siberian Branch, Yakutck (Russian Federation). Melnikov Permafrost Institute
The radial growth of larch growing on permafrost-affected soils appears to be closely related with active-layer temperature and moisture content. The dendroclimatic methods to the study of the response of dominant tree species in the permafrost zone to climatic conditions were used. Analysis of larch growth in relation to air temperature and precipitation indicates that the tree growth is strongly affected by summer precipitation and negatively related to air temperature. The correlation analysis of larch tree-ring chronologies from the Tyungyulyu and Churapcha sites shows a strong correlation with soil temperatures at different depths in the winter season. The higher is the soil temperature in winter, the faster is soil warming in early summer which promotes timely onset of active tree growth in the early growing season. In Central Yakutia, summer soil temperatures impose no limitations on the growth of tree rings, since there is a sufficient amount of heat for rapid tree growth during this period. Under drier growth conditions, high soil temperatures have a negative effect on radial increment. Analysis of the tree-ring growth in larch in relation to soil moisture conditions indicates the correlation throughout the growing season. The most significant coefficients are observed for autumn of the prior year. This is related to the fact that in the early growing season larch uses soil moisture accumulated during the previous year. The larch growth has a strong correlation with moisture contents in the top soil layer (upper 50 cm) in October, i.e. during the seasonal freezing period. It also correlates well with soil moisture contents within the depth of 80-100 cm in September and October. This can be explained by the fact that by the end of the growing season the root system of larch uses moisture from the lower soil horizons, since the soil thaws gradually during the summer, with accompanying desiccation of the upper layers.
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