Certified GKH Gardening Expert
Oh no! That is, basically, the equivalent of cutting a person's head off! Sometimes, a tree can be saved with careful surgery as long as the ringing is only a strip of 1 or 2 inches. This is severe damage, unfortunately. This cannot be saved.
The only thing that I can do is provide a link that will help you to keep moose out of your yard in the future. This will offer some information: