ive seen deer rubs where the deer took out so much frustration he ripped the tree to shreads and broke it and knocked it down...i seen a few like that.....and there aint no moose in PA......elk...but not in these parts.....deer get frustrated when the velvet itches and also when chasing does ect....ive seen it on the discovery channel and thats what they said....they just get angry and let off some steam right into the tree.....id say it was a deer if it looked like a deer rub.....