If he's not the one to do the development, what would be the point? Does he feel the property would be more attractive without trees on it? If that is the case, then to properly clear it, it needs to be done with a D-6 or larger crawler that can remove the stumps as well.
Do the trees have any value? You mentioned "mulch", are there companies that would come and chip up the entire forest for power plant usage or something similar?
If it's allowed, one of the better options would be to burn it. (push the trees into piles and torch them)
