3)Very little of the Southern forests are used for winter heating.

While the forests of the Southern Highlands are so huge that firewood harvesting does hardly make a dent, nevertheless it is a fact that a lot more people in these parts do use wood heat on at least a supplemental basis. Anyone that lives here and knows what they are doing will have a woodstove and a cord or two on hand just in case we lose power for a couple of days in the winter (which does sometimes happen, even in the towns). Get out of the towns and into the backwoods and it becomes a mainstay.

One of the problems with your state-by-state analysis is that there are fundamental differences between different parts of many states. The situation here in WNC is very different from the Piedmont, which is different from ENC.

We probably do have enough forests here in the Southern Highlands to heat all of our homes (at 60F, not 72F!), plus have some for export to other parts of the southeast, all with sustainable harvesting. Air quality would become an issue in the cities and towns, though.