I am highly allergic to poison oak. I have been hospitalize three times over the years with it. Once from cutting a vine of it and the saw spitting sap in my eyes. I got it once up on the on the three rivers fire in No. Calif. that was so powerful, two hours after being exposed my forarms were laid open. I went to a medical mash unit and they insisted I had 3rd degree burns.
Some people don't get it. Could you find someone who's not allergic and have them remove it at the base for you? I wouldn't trust one of them bio suits if their absorbent.
At lest have a Doctor lined up where you can get a steroid shot as soon as your done.
Could you climb above it or is the ivy/oak all over the tree? If you could big shot it and go up and over,you would at lest limit the time you'ed be exposed