Common climatic signals affecting oak tree-ring growth in SE Central Europe

A network of 41 local tree-ring chronologies of oak (Quercus petraea and Quercus robur) in Austria, Hungary, Slovenia, Croatia and Serbia (latitudes 45.00-48.00N, longitudes 13.14-21.63E, altitudes 80-800 m a.s.l.) was constructed and used to establish common climatic signals in oak tree rings in the region. Co-variation of residual chronologies could be resumed in 11 significant principal components (PC), explaining 79 % of common variability. Three of them, PC1, PC2 and PC3, made it possible to identify similarities among the sites. PC1, significantly correlated with all 41 chronologies, indicated a common positive response to precipitation in spring and summer (March and June) and a negative response to temperature in spring and summer (April and June). PC2, significantly correlated with 12 chronologies, indicated a common positive response to precipitation especially in spring (May) and a negative one to high summer temperatures (especially in August) with a pronounced north to south gradient. PC3, significantly correlated with ten chronologies, indicated that a warm previous December and warm current September have a positive effect on tree growth, especially in the south-western part of the study area. The obtained climate-growth relationships will help to understand better the variability of oak growth, to fill palaeoclimatic gaps and to improve dendrochronological research in the region.