Looks like oriental bittersweet painin the backside to get rid of. Sends out runners and spreads that way as well as the billions of seeds the birds eat. Cut it down and paint the stumps with round up.
I peeled a small section and was drying it on top of the stove to possibly make a file handle. After heating it smelled vaguely sweet, and kind of like vanilla. I have the feeling it's some kind of invasive honeysuckle due to the prolific spread, but I haven't been able to find it online so far. When it flowers, I'll try to get a good pic of that, and it might tell what it is.