This vine has been growing with a Tulip Poplar for quite some time, judging by the shape of the tree: Tree trunk The base of the vine has rhizomes spreading out from it like steel cables. Here is a closeup of the vine's bark.
Jeez Loueeze! Strangler fig in Maryland! The lianas have invaded! But seriously...hard to tell with no foliage present, but I have seen poison ivy vines get this thick. Virginia Creeper, too. You are in luck, phlegethon (cool name you have there)---I think Ron B is online, so you may have your answer soon.
It so happens that there was also a gigantic poison ivy vine in the immediate vicinity of the unknown one.
poison ivy can grow as a vine, a bush and a tree. with no leaves there's no way to give a positive id...i'd also wait to get rid of it until you DO have a positive id in case you're allergic to the ivy and that's what it is...
