Still not sure what this "corrugated pipe" around the base is. Is it cardboard, or plastic? Does it have holes in it? And you think the bees are in this pipe? Maybe you can post a pick of it.
First of all, I don't think the yellow jackets are any threat to the tree. If you want them away from the tree, what you could do it cover yourself up, like winter time wear, mask and all, and move that pipe away from the tree. If you can't move the pipe, you can cover it with plastic garbage bags and tie them up, the wasps will leave or suffocate.
If the wasps are coming out of the ground, you can do what other guys have said to do with that, liquid soap and water or whatever.