Large increases in biomass occurred even with water stress. Large effect of elevated CO 2 on water use. There is a strong interaction between CO 2 and light. Light use efficiency rises. Light compensation point decreases.
Lower leaves remain effective longer.
Basal area increased significantly due to CO 2 enrichment in year-1. Daily photosynthetic enhancement by elevated CO 2 varies with time of year. No evidence of photosynthetic adjustments during the first 14 months exposure to elevated CO 2 in the first year. Elevated CO 2 does not seem to alter total water use by pine trees. Stomatal conductance was not significantly different in elevated CO 2 vs. ambient trees.