Can anyone tell me what is happening to my beautiful oak? Thank you for any help you can point to. By the ways the tree is on a bubbler 3x a week. It's other Oaks nearby are fine and it is fertilized. It's a Nuttal oak tree.

It will help to tell us where this tree is growing, and as many other details of its life history and growing conditions as you can provide.

I suspect it doesn't need to be on "...a bubbler 3x a week..." That may be a saturation/wet feet/drowning problem.