Climatic signal in earlywood and latewood of deciduous oaks from northern Italy

Annual radial growth of four deciduous oaks was quantified by measuring two parameters: 1) ring width and 2) earlywood and latewood width. Dendrochronological series were compared with one another to assess the amount of information in earlywood and latewood. For each chronology, response functions to monthly precipitation and temperature were calculated in order to identify climatic parameters affecting ring formation. The study showed no remarkable differences between ring width and latewood width; they are highly correlated and contain the same climatic signal. On the contrary, earlywood series are less correlated to the others and yield nonsignificant response function if only climatic factors are involved in the regression. Earlywood formation seems to be influenced by xylem volume available for water transport and especially by latewood width of the preceding years, rather than by climatic factors.