Hmmm, it could be! Yet I cannot pin down the species. I was going to say Erythrina lysistemon or Erythrina variegata, but the bark and the leaves don't seem to match. I couldn't find a photo of a tree with these leaf-clusters like in that photo. Quite a nice gated community - although I prefer Pelican Crest just a tiny bit - and this driveway with strelitzias and those trees looks fantastic.

The people who originally planted that tree are didn't take care of it. Citrus bark is thin and needs protection from the sun in Arizona. In a tree like that it comes form painting the trunk and any exposed main trunks white with either white wash or white latex paint. I suspect the damage is on the west and south side. That area of the tree is dead. It can no longer transport sugars from the leaves down to the roots and water and minerals from the roots up to the leaves. You have already added to the damage by filling in a hole in the tree. Generally that is a very bad idea. As long as a reasonable amount of bark is still intact on the other side of the tree it will survive. I would paint the rest of the intact bark to protect it from further sun burn and hopefully cooling the living surface and improve its vigor. I would remove any peeled bark since it is dead and can trap fungal infecting moisture and hide predator insects. Another problem I see is improper pruning. You grow citrus up and then allow it to grow back down shielding the trunk from the sun. Also the best and most productive part of the the tree is the lower eight feet that unfortunately plenty of people remove. The last thing of concern is the tree looks buried too deep. If true there isn't much you can do about that but it will severely shorten the life of the tree. Now that i have looked at the other pics you took I am concerned there is no part of the lower bar that is intact which means the tree is dead. It may take a couple of years depending upon how much nutrients are stored. But it will die. The advice to plant a new tree nearby is a good one if you own the place and are going to be there for years. Here is a link that might be useful: AZ Coop Exch. pubs citrus

Interesting question and this response is speculative. Certainly living things will exist in the shredded bark and chips. As the wood debris (chips & bark) decompose there'll be even more living things present. It's an assumption that the cherry died of a disease which is transmittable through the new mulch. It may be the disease needs cherry sap, cambium or some other part of the living tree, too, so that the invertebrates, fungi, etc. won't spread. If existing cherry trees are adjacent to the felled tree, then I would expect the risk is greater. If there are no other cherries near or no cherries at all it's probably safer to leave the mulch. I tend to think that mulch is helpful rather than harmful? It might also depend on the region, climate and species of tree. We planted over 30 trees the year-before-last and there's no evidence that the redwood mulch causes any increase in pests or fungi. Our area is dry (Rocky Mtn.) and NJ may be different in this respect? All of our trees are healthy but they are conifers and as can be seen they are resting in deep mulch.

I don't think that is a disease. I think the damage is from birds or insets.