I am hoping for more details about your sick tree. Could you send a picture or describe what it looks like? Does it have large leaves or needles? What part of the country do you live? If the limbs or branches are falling off a tree and there are no green leaves left then I suspect the tree has died. The best idea would be to cut it down and either dig out the roots or place a pot or some other garden art on top of the cut stump while it rots. So sorry for your loss but now you get to visit a nursery and find a healthy plant to take the place of your sickly tree. Keep growing, Marianne Binetti