Fig. 1

Volumetric soil water content (SWC; %) of the 64 trees during the 6 weeks of the experiment. Week 0 (April 4 to 8), week 2 (April 18 to 22), week 5 (May 9 to 13), week 6 (May 16 to 20). The well-watered trees are represented by circles and the water-stressed trees by squares. The level of significance of the SWC effect is indicated by asterisks: ***P < 0.001, **0.001 ≤ P < 0.01, *0.01 < P < 0.05. Different letters (a, b, and c) indicate significant differences (p = 0.05 by Student’s t test) between weeks