Tree growth and leaf morphological measurements
On July 25, just before the onset of defoliation and drought treatments,
we quantified for each tree initial d 2has a proxy for initial aboveground biomass (as for Experiment 1, above).
On September 18, the final d 2h was again
measured for all trees. Forty-two days after initial re-watering, trees
were harvested. Intact stem sections, newly grown tissue (new side
shoots, petioles and leaves that developed after the stress treatment
application), and old leaves that developed before the stress treatment
applications were separated and oven-dried. Before drying, the surface
area of a randomly selected subset of 15-21 newly grown leaves (without
petioles) per tree was measured again using the LI-3100. These leaves
were then oven-dried, weighed and their SLA was calculated (see above).
Weight of above-ground tissue produced after the drought event, total
above-ground tree weight, leaf weight (without petioles), LWR and SWR
were quantified.