Radial growth patterns of Siberian larch in plantations of the Republic Mari El

Abstract

Based on the measurements of 83 wood cores, the main patterns of changes in the width of the early and late zones in the annual ring of Siberian larch trees (Larix sibirica Ledeb.), as well as their total radial growth indices in the conditions of the Republic of Mari El were identified. It was found that the width of the early wood zone varies in trees from 0.15 to 11.3 mm, late wood – from 0.05 to 4.15 mm, the proportion of latewood – from 1.2 to 82.8 %, and the annual growth indices - from 13 to 423 %. The main factor in the variability of the total width of the annual rings and the layer of early wood is the age of the trees, and the contribution of weather conditions and other unaccounted factors (noise) to the overall variance of the annual growth parameters is no more than 20 %. The variability of the total width of the annual ring also depends on their genotypic features, which determine up to 42.7% of the total variance of the parameter in some cenopopulations. In the dynamics of the growth indices of larch trees, despite the existing specifics of each cenopopulation, the general sharp decline in their values after the droughts of 1972 and 2010, as well as the alternation of the periods of growth and decline, is clearly distinguished.