Cut it a few inches from the ground. I use a pair of hand pruners. Then put something like stump killer (not diluted) on the fresh-cut stump. The herbicide will kill the stump and the vine will due because it has no roots. You can remove after it withers and dies but you can still develop a rash so long sleeves and gloves are needed.
Poison ivy spray usually comes with a wand that you can set for different spray patterns. You can set it just to spray on the poison ivy and not surrounding vegetation. It takes a bit of time to be so careful but it is well worth it to get rid of poison ivy in places that you traverse on a regular basis.
Round-Up.......cut if off,wearing mask & gloves and long sleeved pants shirts remove tops put in garbage bags( thoroughly wash clothing shoes tools anything that you have used to remove the tops;get 2 gallon pump sprayer(not a back pack don't risk leaking solution on your back) buy concentrate Round-Up & add food coloring to it(so you can see where you are spraying it) as soon as you see new leaves growing on stems spray them heavily with the Round-Up. It is absorbed into leaves them stems then kills root systems. Round-Up works best when plant is in vigorous growth after being cut off & new leaves are emerging.Keep checking for new growth and spray thru out growing season.Depending how big the area is it may take a few weeks to get it all. Put spray nozzle down onto leaves when spraying & do not spray in wind or breezy conditions;use gloves;do not walk or get in wet solution. Follow the safety instructions on container they are & have always been on the container for a reason.it won't hurt you or the tree if you do it this way
Thank you to everyone for your help, I truly appreciate it!!!