Stop the dieback

[Auffi]

Hi, last year my aunt wanted to get rid of some trees. As I'm interested in bonsai and it was my first year with a garden I took it home (beech or hornbeam. Can't tell at the moment. Sry). nothing but the trunk and a few roots. To my surprise it survived, grew a little last year and even survived the winter. I like the root base and the curve of the trunk. The new leader is obvious and my plan was to cut/carve right there where the dieback is showing now. And there is my question. Will this dieback stop? Do I have to stop it? How? Cut around seal? What else can or should I do? (I'm a lurker for years but it's totally different when there is a real tree suddenly.

https://imgur.com/a/vX6HcqY

Thanks, Marc

 

[just.wing.it]

That's a Hornbeam.....nice trunk!
I would let it grow for another year before carving.