When hewing with the long broad axe, I have never had any trouble with hitting the dirt even with timbers very close to the ground. My motion with this axe is usually vertical too, but I am relying on the axe's own weight combined with the mechanical advantage derived from the long handle to do all the work, and not actually swinging the axe. This means that in most cases, the wood just splits away calmly, and the axe doesn't fly through.
It is also very important not to try and remove and entire juggle as one solid piece on thicker sections, but to remove it in sections. This way the wood can easily split away and you don't have a sudden release of energy when it split off. In addition, when you are removing wood you finish your swing with a slight snap of the wrists, which gives the axe a kind of slicing motion, then when it is embedded in the wood you pry the piece of wood free with the axe. I tend to finish out the bottom of a section with slow, gentle, sweeping cuts that sometimes run more horizontal.

This long axe is single-beveled as well.

Was de eine ilüchtet isch für angeri villech nid so klar.