I've used a product called "Tree-Kote" with good results. It's a black, tarry goop that come in a metal can with an enclosed applicator brush attached to the screw lid. It also comes in a spray form like paint. I've used Tree-Kote on my trees at home when I prune a limb off with good results. I think the trees heal fine on their own, as long as bugs or rot don't get in the wound - and that's why I use the Tree-Kote, to seal the open wounds. I've never had a bad outcome from using Tree-Kote. The bark heals from the outer perimeter of the wound inward. My BIG pin oak and our home crab apple trees are my test cases - all healed nicely.
Natty's idea of cleaning-up the rough edges is smart. Cleaner wounds heal better and quicker. Less shredded areas for rot to take hold. Clean edges can begin to heal more easily, IMO. ------- FWIW.