It was too dense, and inner parts would die soon without light.
When you neglect pruning and partially defoliating hornbeams, you will be left with long branches with foliage only on tips and long internodes.
Mimo, don't you think the first branch is getting a little too thick? It's almost like a second trunk.
In fact I like this tree very much, and I am jealous, of course. But...
I am wondering if there is a way to stop branches from thickening when they get "there".