Fruit tree question?

[histopicker]

I was watering my fruit trees yesterday and found a problem. One of my cherry trees was leaning a little so I wiggled it and it fell over. Some critter had chewed the tap root clean off!!! I don't know if it would be Chipmunk, gopher, rabbit in a den, ground squirrel, pack rat, or what. It looks like it was whittled with a pocket knife.

[bk]

Have had the gophers do that to me in my part of the country.   If you dig around where the tree was, you might find tunnels.

And why does it always have to be a tree you want that they kill?