Thanks all. Note that in addition to being a gardener, I love birds and in fact try to attract them to my yard via feeders, birdbaths etc. So I would never want to wantonly remove a haven for birds. However, I also understand the value of trees, which are unfortunately grossly under-appreciated, and their contributions grossly misunderstood, by most people in NYC. So this is why if I think a tree is at risk, that I should do what I can to save it. I also read a terrific book recently, "Bringing Nature Home: How Native Plants Sustain Wildlife in our Gardens", and it talked about this very thing...how non-native plants (such as English Ivy) can dessimate native plants/trees. As for those who mentioned that sometimes the ivy itself helps to anchor a tree, well I'd imagine that if a tree needs that kind of help in keeping upright, chances are it wasn't much longer for this world to begin with. But I'd suspect that in many instances, it's a case of ivy simply growing up and eventually masking an entirely healthy tree, and that eventually the ivy will block out its ability to take in sun. So at this point I still plan to cut as much of the ivy as I can without damaging the tree bark itself. Tx!

Possibly Euonymous fortuneii aka Winter Creeper but I don't know where it's growing so might be totally wrong.

Well ken, why didn't you just write that in the earlier post? This: are there perennial morning glory??? [or is this one of those that is annual for me.. and perennial in more temperate areas?] too lazy to look it up.. bear with me ... Didn't give the impression of your later post's statement: i was trying to make the OP ... original poster ... go out there and observe ... If you wanted details of the vine's trunk from the OP, why not just say that is what you wanted? Instead it is hoops and goose chases... fakes and feints... Most of us that take the time to reply to queries in this forum are trying to assist the posters and address anyone's follow-up questions. It is a waste of our time to be asked questions when you are not even interested in receiving the answers.

Thanks Floral_uk z.8/9 SW UK, that put me in the right direction. It looks like thorny dewberry (without the hairs)