It has to be a very large operation to be economically viable. Any operation making wood biofuel would likely be large enough.
I've never been in large scale timber harvesting, i just think it's real cool. If I hit Powerball, I would probably start my own timber harvesting/land clearing business for fun and profit.
I'm the first guy in my neighborhood out and about after a good size storm that includes damage,I never pass up a chance to fire up the old saw!