I think in my opion that you could use a metal detector i don't know if you can still buy them these days but im pritty sure you can. Then you could put it against the tree and see if theirs anything inside it.
just get some bee killer stuff and angle it down the hole if there is one and spray all around the trunk until fully covered, wait 24 hours at the least before checking again, if thee are still bees,...
The trunk is the main structural support element of a tree; trees elevate their leaves by means of the trunk, lifting them above lower competing vegetation.
The trunk is the main structural support element of a tree; trees elevate their leaves by means of the trunk, lifting them above lower competing vegetation.