Chelean Mesquite Tree
I have a chelean mesquite tree that seemed to have died, but it is shooting out branches from the bottom that are beautiful and healthy, but the original trunk is dead. What if anything can I do? Its a beautiful bush.. ha ha ha Lynda Burke
Your tree is a grafted tree, and it seems the tree is only growing from the root stock.
There isn't really a way to know what the root stock is. You may want to look for a replacement.