Well there are lots of signs of problems, but not enough information to really know what's happening with your tree. I notice there is no exposed root flare, which is a sign of improper planting, but that doesn't mean that that necessarily lead to the problems we see now.

If we knew more about the planting process, conditions at the site, and timeline of symptoms, it's possible that something would give clues to the problem.

Planting a Tree or Shrub

p.s.

Also, tell us about how you have cared for your tree. Have your watered regularly? How did you determine when to water? Other factors that come to mind? Etc....