This is a mod that aims to do a little realism into cutting trees. It offers a "super" variant to all common axes (at least those found in the Asuna game).
This super axe functions like this: Once it detects that you're trying to chop a "tree", it does a breath first search from the level you dig at to wherever it can reach. All found items are added to a stack and then it begins chopping from the top down again. Each chop wears the axe as a normal one would, so it's best to find a better axe to turn into a super axe.
The super axe can be created by combining an axe with a star fragment from the astralcraft mod. (this is also included in the Asuna game). The resulting axe will have the durability of the axe used in the combination.