I was thinking, wouldn't it be easy to implement natural plant speading?
Tree's could drop their seeds, and the it would check the distance of other trees. If there isn't one within 5-6 tiles, it starts growing.
You could also have them check to see how far away the nearest plains are. This would give the edge of forests. Same with paved tiles.
Also the ability to have the trees fall in the direction you're facing when you cut them. This way the logs don't get caught in other trees.