Extracting Climatic Information from Stable Isotopes in Tree Rings

Abstract

Trees provide within the physical characteristics of their rings (width, relative density, reflectance), a record of past environmental changes, which, when expressed strongly, may be used successfully to extract palaeoclimatic information. Such approaches are now well established and have been applied globally. Trees can live for many hundreds or even thousands of years; it is, therefore, possible using these physical parameters to reconstruct climatic change throughout the life of the tree. Along with these established physical proxies, the stable carbon, hydrogen, and oxygen isotopic analyses of tree ring series provide a powerful suite of additional climate proxies. In comparison with the measurement of the physical proxies, the analysis of stable isotope ratios in tree rings is demanding, in terms of both personnel and resources. Consequently, the stable isotope analysis of tree rings can only be justified if the resulting data can provide additional, reliable climate information that cannot be obtained through alternative methods such as ring width or relative density. This chapter provides an introduction to the application of modern stable isotope techniques for the reconstruction and study of past climate from tree rings. Current challenges and limitations are discussed with specific emphasis placed on the development of robust isotope-based palaeoclimate time series and their potential for both isotopic and multiproxy analysis, using examples from a well-replicated site located close to the Boreal tree line.