High-resolution stable isotope analysis of tree rings

Tree-ring d13C variations have long been recognized as valuable archive of climatic information, but studies in the past focused on inter-annual patterns. In contrast, high-resolution intra-annual d13C studies are still rare. The reason is the time-consuming preparation, but also the limited understanding of such sub-annual patterns, which can be blurred by mixing of stored carbon and fresh assimilates used in tree-ring formation during different growth periods. Nevertheless, high-resolution analyses hold great promise as they could result in unprecedented and highly valuable intra-seasonal climate reconstructions, revealing the occurrence of dry and wet periods throughout the growing season rather than an average only. Here we will use a novel laser-ablation isotope-ratio mass-spectrometer to produce the data richness necessary for systematic assessment and understanding of the climatic information imprinted in the intra-ring isotope signature for different species and environments.