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At each visit, we chose young, fully developed leaves from two sun exposed branches of each selected tree. Leaf gas exchange measurements were concentrated in the morning. Sun exposed branches were excised and the cut end of the branches immediately placed in a bucket and then recut under water to re-establish the xylem water column. For each leaf, approximately light-saturated (1500 µmol photons m-2 s-1) measures of net photosynthesis were taken at ambient CO2 concentration, 400 µmol mol-1 (ppm) (A400) and then at 1500 ppm (A1500). The leaf was next wrapped in aluminium foil for 30 minutes before respiration in darkness (Rdark) was measured, still at 400 ppm CO2. Air flow was held constant and a constant chamber block temperature was adopted, set marginally (ca. 1°C) higher than expected morning air temperatures to counter the effect of transpirational cooling and to ensure leaf and ambient air temperatures were similar.

On completion of the gas exchange measurements leaves were weighed for fresh mass and scanned for leaf area before being dried in an oven at 70 °C for a minimum of 48 hours, after which their dry mass was recorded.

Oven-dried leaf material was used for determination of total leaf nitrogen and phosphorus: dried ground leaf material was hot-digested in acid-peroxide before colorimetric analysis using a flow injection system.