Here's the photo, for others:
Unfortunately, yes, that looks like poison ivy.
I've dealt with it, it's not fun.
If you want to deal with it yourself, I recommend that you get long rubber gloves and some Tecnu:
Also wear clothes you wouldn't mind tossing.
Then you can proceed in a few ways.
One is to just tear it off of the tree. Depending on the size, that can work fine.
A vine going up the tree that much probably has a corresponding vine/ root system that you'd also have to find and dig up. If the ground is saturated, this can be relatively easy. If the ground is dry, it's harder.
I'm just here for a minute so will leave things there for now, let me know if you have any questions so far.