As far as poison ivy vines in trees, it's best to sever the vines near the base of the tree first. Use a hatchet or machete. Spray any ivy resprouts near the tree. I've never killed a tree using the method.
I have killed several invasive trees with triclypr; Bradford Pear and Tree of Heaven. To do that, I drilled 3-4" holes at a downward 45° angle and poured in straight triclypr.
I have killed several invasive trees with triclypr; Bradford Pear and Tree of Heaven. To do that, I drilled 3-4" holes at a downward 45° angle and poured in straight triclypr.