Certified GKH Gardening Expert
It's going to be important to examine the healthy-looking side of your tree. Look carefully at the branches, stems and leaves to see if there may be some kind of disease or pest problem. If not, you may have a root problem. Could the roots from the dead half have encountered pavement or something else that may have injured them? Prune out the dead branches as soon as possible. We recommend contacting your county's extension service for help to see if the rest of your tree can be saved.