Trees as living organisms respond to environmental impacts in various degrees. With environmental changes, adaptations on various levels are needed to ensure survival. The most regularly reoccurring environmental changes are temperature, precipitation and water availability as a result of seasonal changes during the vegetation period. Such changes lead to different physiological response patterns, which effect the isotopic composition in plant organic material. Thus the stable isotope composition of C, O, H and N can serve as indicators and Proxies for various environmental impacts. Tree rings are an ideal matrix for such these isotope data, as they are renewed yearly and store this information for centennials to millennia. The year by year or even intra seasonal decoding of this isotopic information provides a powerful data set, which in combination with classical dendrochronological information represents a tool for the retrospective reconstruction of environmental changes. This can be climate reconstruction, understanding the effect of increasing CO2 over the last 150 years, or the effect of varying air pollution loads on the tree cover world-wide. Thus the use of isotopes (stable and radiogenic) in tree ring material represent a powerful and valuable archive to unfold past environmental changes and their effects on the vegetation.

For this session we invite contributions using stable (C, O, D, N, S) and radiogenic isotopes (14C) in tree rings as indicators of physiological responses to environmental changes.