From your photos, I believe this was probably the rootstock of a Mulberry, but I can not be positive. The landscaper or designer who planned this commercial area did not intend the tree to look like this.
The original tree could have declined from water stress, freeze damage, a car accident, or something else that required the mine trunk to be removed, and then they allowed the suckers to grow and become a multi-trunk oversized sucker.
If you see flowers in the spring or fruit I could give you a more positive identification.