I have a crab apple tree in my backyard in Lakewood Colorado that is quite large and old, from reviewing your list of varieties I'd guess it's a Dolgo? It is in rough shape with damage that I presume to be sun scald, bug damage, and some kind of infection. It is the anchor of the back yard, providing so much of our needed shade and would be an expensive pain (and heartbreak) to remove. I'd appreciate any help on how to care for it. Background: When I moved in 4 years ago I could see some signs of bugs. I noticed small ~1mm holes in the bark from some kind of bug. I did see Pigeon Tremexes on it from time to time but I can't say if that's the only bug responsible. There was also some mild bark peeling that revealed insect tracks on the hard wood. The peeling bark has gotten much worse, primarily on the South or South/East aspect which makes me suspect sun scald even though it's a very mature tree. I had a respectable arborist company come in early 2023 to look at and trim trees as necessary. They thinned the crab apple tree quite a bit and offered to spray a pesticide which my wife declined. In the two summers since being trimmed the tree has taken a hard turn for the worse. Last summer it was primarily the bark peeling that progressed. And this year some branches failed to bud/fruit and many others got leaves just to drop them in late spring. Any advice is appreciated this tree means a lot to me. Thanks