I don't think that "tuber" is the correct discription of the root of this plant.
Mr. Garner notes that the Stretchberry Greenbriar parts are
edible. The new growth at end of vines can be munched, the roots
and shoots boiled or raw, the pulp of the little black berries added
to Sweet Gum sap to make bubble gum, and the rizomes dried, chopped then
pounded in water , the fibers strained out, the flour allowed to settle
to the bottom and the excess water poured off and used wet for flour or
the flour can be dried for storage.
I have never tried this and he warns that there is another plant, Snail
seed vine, Cocculus cadolinus, that is poisonous and looks
pretty much like this except no thorns and berries are red.
To me, the plant is definitly a neusance and I could live without it.
I'm sure someone will write me in a huff telling me how this plant saved
his/her life when they were stranded in the wilderness, or how his/ her
ole gran'pappy ate it all his life and lived to be 106.. but that
is ok.. I am open minded. ...that doesn't mean my mind is like a sieve,
though! : )