apple tree – bark damage – some parts weak possible breakage
Good Afternoon, Old apple tree - over period bark peeling thought at first fox damage, but my neighbour suggested is it possible local garden owner may have used some form of poison to deal with the dreaded vine and caused that situation to effect the tree, Regards. Alan.
Peeling bark could be from sunscald, disease or pests and of coarse the two possibilities you list also.
Inspect the tree more closely for any other signs of pests, cankers, leaf diseases.
These links have more information.