Characteristics of radial growth and stable isotopes in a single oak tree to be used in climate studies

In this study we have analyzed the variability of tree-ring widths and stable isotopes (δ13C and δ18O) of a single sessile oak tree (Quercus petraea (Matt.) Liebl.) since these parameters are critical in reconstructing the environment, particularly climatic conditions. Tree rings were separated into early- and latewood (EWt; LWt), tree ring (TRt), and transfer tree ring (TTRt, the latter being the latewood plus the earlywood of the subsequent year. Mean sensitivity, simple correlation, partial correlation and autocorrelation analyses were applied to describe data and relationships. Although this research focused on a single tree, the results compared well with average site data. Widths and δ18O values showed generally low autocorrelation for all tree-ring components, whereas δ13C revealed highly significant autocorrelations for most tree-ring components. Mean sensitivity of the standardized values turned out to be high for δ18O, marginally lower for width and the lowest for δ13C. Correlation analyses have proven that the relationships within the tree-ring widths or within the isotope parameters are much stronger than across widths and isotope parameters. The study demonstrates the unique potential of all measured tree-ring data to be used as climate proxies.