Hello. There is a lovely willow tree in my back yard that seems to be dying. About 2/3 of the tree has very scraggly branches, while the one area has nice, long weepers. The trunk is obviously very odd, too. It's been fine until this year. We have very sandy soil, too much ivy, and at least one very pesky mole. I'm not sure if any of these is killing the tree, though. I have started to remove the ivy. Any advice would be greatly appreciated. Thanks.