Hope you're right FN. The older tree is certainly dying - all but 2 scaffolds died last year. But when I saw the tree next to it peeling bark so copiously, so much like the dying branches on the other tree, I began to worry.

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

I may be judging some peoples thoughts on here unfairly, and maybe I'm the one who's wrong. But, Not all trees are symetrical and perfect. Trees get burls,galls uneven growth if one side is shaded etc. Some times your mulch gets dog vomit fungus and your tree gets Slime Flux. It isn't all perfect, but, it's normal, and no cause to just throw it out and start new. Yes, sometimes you need to get rid of a diseased tree and start with the new, but, I just don't see this (the Op's) tree as a lost case to get rid of. This is likely why ( at least in the US) there won't be many old tree specimens to show future generations. I realize if there is an old tree near a house ready to fall it should be cut down, but, the younger generations (no I'm no crotchety old man) will just get rid of trees that are breaking down, even if they are away from buildings. In the UK, it seems they remove any rotten wood, then fence around them, so nobody will get close enough to get hurt easily. Then the tree continues to put on growth in girth, if not height, and it is a sight to behold, and of great age. I need some unicorn blood to make sure I can be around and make sure nobody cuts down my English oaks and white oaks. I'm kidding about that of course. I don't mean to be ignorant to Logan and anyone. But, trees get better with age, and don't need to be perfect, they are shaped by their environment. In the forest they don't have limbs until many feet up in the tree because of growing in the forest environment. I guess if you are in a HOA neighborhood, and all has to be perfect, you will think if it isn't perfect it has to go.

I wouldn't cut the whole thing off at once. I also wouldn't have cut that large branch out of the center, resulting in a conspicuous pruning wound in the middle of everything, or done anything else to "arborize" (make tree-like) a cane-stemmed type of shrub such as this one. Unlike kinds like hollies and rhododendrons shrubs of this nature often do not make long-persistent individual stems of a permanent and solid nature that always last the entire life of the specimen in the manner of true trees. When a cane-producing shrub is pruned and trained to have everything coming off a single main stem the entire specimen may be lost if and when this one cane ages and deteriorates - well before a stem of a tree or tree-like shrub would have.