Fill a hole in a tree
Where a big branch comes off of the trunk of a large oak, there is a hole that fills up with water and debris. What can I do about it? I'm afraid it's going to rot and the branch will eventually fall
Certified GKH Gardening Expert
This article will help you.
I've seen that filling with hole with some expanding foam, like I'd use for a hole in the wall of my home, would that be beneficial for my concern?