As far as carbon is concerned new plants consume far more carbon than older, established plants. The new trees that will come up after older ones have been cut will consume far larger shares of carbon. So in effect harvesting trees can actually benefit the environment instead of hurt it. The key to it working is simply taking only the oldest trees and taking no more than is ecologically viable at that time.
Thanks for the replies, all of you.
They definitely helped me answer my question.