Hello John,

You have a beautiful crabapple tree. It looks like you have some sunscald going on in your picture caused by the bark heating up during the day and freezing at night. I see a lot of reflective surfaces in your picture which can heat up the bark. A southwest exposure can also cause this problem. Apple trees can be susceptible to this disease. If the cambium just under the bark is damaged then that part of the tree can die. You had mentioned you had some dead branches. I have included sunscald information from Utah State University Cooperative Extension.

https://forestry.usu.edu/files/utah-forest-facts/sunscald-injury-or-southwest-winter-injury-on-deciduous-trees.pdf

Some crabapple trees defoliate naturally, check under the peeling bark, if you see more bark then this is a natural process. If you see bare wood under the flaking, then there could be an environmental or disease cause. A disease called fireblight can cause the bark on the trunk or branches to peel and kill branches or the entire plant.

https://extension.colostate.edu/topic-areas/yard-garden/fire-blight-2-907/

https://extension.colostate.edu/topic-areas/yard-garden/environmental-disorders-of-woody-plants-2-932/

Wildlife such as deer or squirrels can strip and eat the bark of crabapple trees. I have included a link with more information about this problem.

https://planttalk.colostate.edu/topics/wildlife-issues/2303-squirrel-damage-trees/

You are welcome!  Thank you very much for your reply.