The article did mention this. The problem is that, while trees absorb a lot of CO2 in the spring, they emit most of it in the fall. Freeman Dyson had proposed a solution whereby we breed a special kind of tree that stores most of the CO2 in its roots, rather than emitting it in the fall.
For what it's worth, that is the most pleasant method the article mentioned.
That might turn out to be a feature - more carbon in the winter and less in the summer could = smoothing out seasonal variation, if my wild speculation is correct.
At any rate, I don't see how you could turn a desert or a field into a high biomass forest without sucking up lots of CO2. Of course, once it's full-grown it will be in equilibrium, losing carbon as fast as it gains it.
Unfortunately trees don't largely suck as much carbon dioxide out of the air as people used to think. In some studies, its being found that forests produce more co2 than they absorb through growth.
With that said, I completely agree that we should plant more forests. They have many benefits to the environment even if the co2 argument is out. Decreased erosion, increased rainfall, and increased animal habitats.
