Inter-annual variation of tree-ring width, δ13C and δ18O in juvenile trees of five plantation poplar cultivars (Populus spp.)

The maturation effect and the respective interaction have resulted in large temporal variability in the present three investigated tree ring traits. However, the impact of two drought vegetation periods (2003 and 2006) was still reflected by the juvenile tree ring records of all traits. Different juvenile trends in the records of the stable isotope ratios δ13C and δ18O, and the trend slopes, which may vary between genetically different cultivars, must be considered in tree ring investigations of SRC poplars.