Chinese Pistache Berries but no leaves

[JeffC.]

Hello all
I have a 16 yo Chinese Pistache. This year it has berries, still green, but no leaves. We are in the middle of summer and normally by now it would have full foliage. It has one sprout of leaves that are green but the rest of the tree has green berry clusters all over. Any ideas if it has a problem?

Befuddled

 

[JeffC.]

Just to clarify. The tree has green berry cluster all over. The berries have been green and plentiful for about 2 months now, maybe a little longer. I have one minuscule budding of leaves on one limb. There are no other leaf cluster anywhere else on the tree. This is the first year it has not had a full coverage of leaves. We have not had any harsh freezes. We have an irrigation system so it gets watered weekly.