The property I bought last year had poison ivy/oak vines growing up many of the trees all the way to the canopy. The vine stems/stalks were of all size from 4mm wide to 10cm(seriously) they were choking the trees. The way I tackled this oozy itchy blister rash plant without wide spraying of herbicide was to cut through each vine and apply a herbicide gel to the cut ends. It worked extremely well without harming the trees. Alright so here's why I typed all that. On some of the thicker vines I did not cut all the way through some I cut 75%-90% through then painted the herbicide on even with just 10% of the vine intact with poison on the cut ends they survived. Amazing how resilient plants can be. I really minimize the amount of poison I use but it was a poison ivy jungle and really not many other options that wouldnt result in me covered in blisters and the trees unharmed.
It baffles me how I manage to kill some plants I'm trying to grow