Pruning is necessary to maintain a healthy, vigorous tree.
Maintain or reduce tree size. Pruning can prevent a tree from overgrowing its space in the landscape and eliminates the need for drastic pruning.
Remove undesirable growth. Pruning can encourage tree vigor through the removal of weak, overcrowded growth. Such thinning often improves the visual balance or symmetry of the tree.
Remove dead, diseased, or broken branches. Pruning will aid in maintaining the shape, vigor, and health of the tree.
Stimulate flowering and fruiting. Removal of the current year’s old, faded flowers and fruit clusters will promote flower buds for the following season.
Prevent damage to life and property. Pruning can minimize the hazard of limbs interfering with power lines or overgrowing structures. It can also remove weak crotches before limbs break in strong winds and open blocked sight lines caused by overhanging limbs at driveways or street corners.
Shape trees in an artificial form. Pruning and shearing can be used to shape trees as hedges or form rigidly formal espaliers or topiaries.
Source: Pruning Ornamental Trees and Shrubs, Michael Dana and Philip Carpenter, Purdue University Cooperative Extension Service, Department of Horticulture
Pruning cuts should be made just outside the branch collar. The branch collar contains trunk or parent branch tissue and should not be damaged or removed. If the trunk collar has grown out on a dead limb to be removed, make the cut just beyond the collar. Do not cut the collar.
If a large limb is to be removed, its weight should first be reduced. This is done by (1) making an undercut from the limb’s point of attachment. Make a (2) second cut from the top, directly above or a few inches farther out on the limb. Doing so removes the limb, leaving the stub. (3) Remove the stub by cutting back to the branch collar. This technique reduces the possibility of tearing the bark.