Which would be an absolutely huge (and practically impossible) change in, say, Western Europe. Maybe 80–90% of all farmland would have to be reforested. It was difficult enough to get people to agree on the 20% goal of EU's Nature Restoration Regulation.
It depends what preindustrial means exactly. Most of the forests in Western Europe were cut well before that, I believe around 1800 is actually the trough. Your 80-90% figure is probably back to the original state, but I would guess it's antiquity or pre-antiquity levels.
