If an unsightly, diseased or broken tree branch needs to be removed, take care to protect the tree from harm. Improper pruning can make trees vulnerable to disease and pest infestations. Start by shortening the branch to a stub about a foot long. Make a cut on the underside of the branch about a third of the way through; then about an inch further out, on the top, make a second cut, cutting until the branch breaks off. Then make a final cut to remove the stub, taking care not to cut into the collar where the branch joined the trunk of the tree. Eventually this "wound" will be sealed off by callus tissue. A diagram is in "The Sunset Western Garden Book."