I know only a little about this, but I think the problem with fast growing trees is that the wood tends to be of low quality for commercial purposes. A while ba

I know only a little about this, but I think the problem with fast growing trees is that the wood tends to be of low quality for commercial purposes. A while back eucaplyptus trees were planted all around the world, but turned out to not be very useful as lumber. I think they're mostly now used for paper pulp, which is still useful, but much less valuable than timber. If the aim is to just regrow a forest quickly then maybe it doesn't matter. But I think there's probably a difference (aesthetically, if nothing else) between a healthy "natural" forest ecosystem and a plantation all of the same type of tree.