What was done
The authors grew 34 trembling aspen (Populus tremuloides Michaux) clones in pots in greenhouses maintained at atmospheric CO2 concentrations of 375 and 800 ppm for 95 days, after which they assessed the growth responses of the vegetatively-propagated plants.

What was learned
The mean CO2-induced growth increases experienced by the 34 clones were: 42% (leaf biomass), 83% (stem biomass), and 136% (root biomass).

What it means
The authors say that "for agroforestry/afforestation, both early establishment and maximum growth are of interest," and that "in reclamation, large root systems which help ensure survival and rapid uptake of water and contaminants, would be important."  Hence, it is clear that elevated CO2 concentrations during greenhouse growth prior to out-planting can increase the productivity and modify the morphology of vegetatively-propagated aspen clones in ways that increase the likely success rates of these enterprises.