It’s difficult without flowers & its location (this will help to narrow down its genus & species). Please resubmit with closeups of the branches & main trunk. I have some ideas but need to see more of the plant & its location. I could be wrong, but it appears there are two different plants in the pictures? The leaves in the bottom of the photo, to my eyes they could be a species of buckthorn (Rhamnus) perhaps? A closeup of leaves & main trunk would help more. Check out images of a species of buckthorn, the common buckthorn (Rhamnus cathartica). If this isn’t that, please re post with details mention above. Thank you & best wishes! https://www.invasiveplantatlas.org/subject.html?sub=3070