Canada opens first bio-powered power plant

I just saw on CTV news that a small town in canada is the first to use this technology, a power plant which creates absolutely no harmfull environmental effects. What they do is take trees and grind them up into sawdust, then they vaporize the sawdust and convert the vapor into this bio-oil that is very long lasting and 100% clean burning.
now I'm not really sure where I stand on the issue however. I mean sure there's no more pulution, but is using trees as a source of power really sustainable? I suppose you can replant trees as you harvest them, but there's no way they can grow back as fast as we use them, should this become wide scale (as the industry hopes to do). not really sure where I stand on this, what are you opinions?