I've been out of town for 3 weeks; I got back last night. My sour
cherry tree looked perfectly healthy when I left, but now all the leaves
are dead and brown -- except for about 10 leaves that aren't *quite*
dead yet. I looked around the base of the tree for signs of a peach
tree borer, but nothing. I also don't see any insect or mite damage to
the leaves. The ground under the tree is neither really dry nor really
wet. I don't see any twisted growth like you might find if someone
sprayed it with herbicide.

Any idea what might have caused this? Is there any hope for the tree?

Best regards,
Bob