TreeDimensional

Wow, your tree has suffered a severe setback. From the pictures of the leaves on the twig on the main stem, I would suspect chemical damage. We need to know what was sprayed on the tree and where, we also need to know what the chemical was and the target (fungus, aphids). You then go on to explain the root loss, we need to know where the roots were cut. Percentage of root loss is important to determine what is going on with your tree.

The other thing that is interesting is the fact that there was a "structural trim" performed. How much of the crown was removed, and was it recent deadwood or live crown.

Please try to fill in some more of the details, and possibly we can come up with some better explanations.

I see Treelore has posted while I was pecking away at the keyboard. I still need more of your input before I will pass judgement. It is difficult to make decisive judgements UNTIL ALL the facts are presented.