AGE-DEPENDENT TREE-RING GROWTH RESPONSES TO CLIMATE IN LARIX DECIDUA AND PINUS CEMBRA

Abstract

Dendrochronology generally operates under the assumption that climate–growth relationships are age independent, once growth trends and/or disturbance pulses have been accounted for. However, several studies have demonstrated that tree physiology undergoes changes with age. This may cause growth-related climate signals to vary over time. Using chronology statistics and response functions, we tested the consistency of climate–growth responses in tree-ring series from Larix decidua and Pinus cembra trees of four age classes. Tree-ring statistics (mean sensitivity, standard deviation, correlation between trees, and first principal component) did not change significantly with age in P. cembra, whereas in L. decidua they appeared to be correlated with age classes. Response function analysis indicated that climate accounts for a high amount of variance in tree-ring widths in both species. The older the trees are, the higher the variance explained by climate, the significance of the models, and the percentage of ...