Q: This cherry tree is my favorite and its base is showing this damage. I do not want to lose it.
A: I’ve seen identical damage at the base of a flowering cherry that “up and died” overnight. One day it looked good, the next day the leaves were limp and the third day they were turning brown (this was in July.)
When I pulled away the mulch on the tree, there were small animal droppings in the spot, most probably voles. See my similar pix below.