Our cherry tree is located in a school garden and some students were climbing on the tree to pick cherries and broke a branch at the trunk taking some of the trunk with it. It is just a round little cavity where the branch was. Should I seal it or anything?
If you can clean or cut the wound to the branch collar its the best you can do. Pruning 'sealants' etc likely wont do any good. They arent recommended for most pruning wounds or injuries except for a few disease spreading issues (oakwilt and dutch elm disease).