My favorite chopping axe is the Kelly Perfect pattern from Kelly Axe and Tool Works.
The shaded area was hand filed to thin out the blade. This is done on both sides of the axe head. Take notice the thinning doesn’t go all the way to the edge. If you were to taper all the way to the edge it would be a feather edge and very weak.
This edge is very good for chopping wood, but doesn’t take kindly to hitting rocks or chopping roots. It is especially well suited for lopping branches off of a fallen tree.