Most people recognize the three leaves of poison ivy. If you need a reminder, google search the name with “images” to see hundreds of photos.
This picture was taken in winter. Here you’ll see root hairs that attach the vine to the tree but no leaves, since poison ivy is deciduous. (English or common ivy is evergreen, and it also produces root hairs as the vine matures.)
Notice that the vine is starting to encircle the foot of the tree. Carefully cut it with a limb saw, remove and dispose of this portion and extract as much of the root as possible. Keep in mind that poison ivy is native to Long Island, and unless it is creating a health risk leave it for wildlife to enjoy.