It's quality over quantity. Forests tend to recover from the edges. If you spread all of your available resources over a hectare of land, you get something better but not good. If instead you dumped all of those resources into six squares, they get closer to healthy faster and then begin to spread.

I've heard others opine that if we forced foresters to leave a large intact area in the middle of a clearcut, that the land would recover faster. I don't doubt it. I think we could accomplish the same by making them take out narrower strips. It's just not 'convenient' and so they won't unless we force them.