Application of process-based modelling for interpretation of stable isotope variations in tree rings

Abstract

Tree-ring width and stable isotopes (carbon, oxygen, and hydrogen) in tree-ring cellulose are widely used to reconstruct environmental conditions. The application of models capable to describe a variation of stable isotopes in annual tree rings can be a powerful tool for interpretation of environmental changes at the eco-physiological level. In this paper, we modelled carbon (delta13C), oxygen (delta18O), and hydrogen (delta2H) variations at the tree-ring level and compared results with measured data, obtained from the Mackenzie Delta River (68°30′ N, 133°48′ W) for the common period from 1901 to 2009. Using a process-based model (LPX), we were able to simulate carbon isotope values, which significantly (r = 0.29; p = 0.002) correlate with measured carbon isotope values. The model calculations for oxygen and hydrogen require further modifications and improvements, in particular the inclusion of the source of water used by the trees in the Canadian subarctic, as well as delta18O and delta2H in the water.