We had a very beautiful, healthy coral bark maple tree which was about eight
years old, and 10 feet high.

It was destroyed when a nearby tree fell onto it, leaving only a tall stem,
with one sprig of leaves about a foot long sticking out of the side.

Question: What if anything can I do to restore this tree?

You can see a photo at:

https://sites.google.com/site/10test20/