Physiological Measurements
Physiological measurements were made monthly for four months in 2018 and for three months in 2019 starting at 45 DAFB on days that were cloud free and temperature not exceeding 30°C. Means were calculated for all sampling times during the season. Stomatal conductance, transpiration rate and net CO2 assimilation were measured on two sun-exposed mature leaves per replicate between 10am and 12pm using a LI˗6400XT infrared gas analyzer (Li˗COR, Lincoln, NE, USA). Reference CO2 concentration was set at 400 ppm, leaf temperature at 25 °C, and photosynthetic photon flux density inside the chamber was set to 1,500 μmol m−2 s −1. After clamping, the leaf was allowed to equilibrate until reference and sample values stabilized. To assess water status, fully mature expanded leaves were chosen from inside the canopy closest to the base of the tree and leaf water potential was allowed to equilibrate with the stem in a silver reflective bag for at least 90 minutes. Then, stem water potential was measure using a Scholander System Pressure Chamber Instrument (PMS Instrument Co., Albany, OR, USA) at solar noon.