Fig. 5.

Mean species-specific linear mixed model t statistics for the influence of climatic variables and atmospheric CO₂ concentrations on BAI. Mean values exceeding the 95% probability levels are identified by a diamond. Mean r refers to mean values of the plot-level correlation coefficients computed between the fitted estimates from the average model and the response variable. Abbreviations of climatic variables: SummerT, summer temperature; SoilWater, summer soil moisture index; FallT, fall temperature; SpringT, spring temperature; Snowfall, cool season total snowfall; [CO₂], atmospheric CO₂ concentrations. Terms t − 1 and t describe influences taking place in the year before and of ring formation, respectively; n is total number of sampled years.