Fig. 3
Mean daily sap flux (F H2O), CO2 flux through xylem (F T), and dissolved CO2 concentration at stem base ([CO2 *]base) of 16 stems belonging to two large and two small clones in a coppiced Quercus pyrenaica stand measured during the growing season of 2012. Since F H2O and F T were insubstantial before and during budburst (DOY 101–145), data from DOY 146 to 200 were used to calculate the means. Different letters indicate significant differences within clone for [CO2 *]base (italic), F H2O (capital), and F T (lowercase) (Tukey’s test at p < 0.05)