A living fence or a green fence uses natural growing vegetation as a fence barrier.
Tree Posts
Using trees as living fence posts saves you time and money when putting up a fence. A disadvantage is you don’t get to pick where the posts should go and you can’t be obsessed with straight lines.
Take a pressure treated board and attach that to the tree, then add your fence hardware to the board that you’ve attached to the tree. What that does is it allows the tree to grow against the board without consuming all that hardware over time.