Thinning can be used to reduces resistance to wind and to reduce stress during drought periods or following construction damage. First remove dead, broken, weak, or diseased branches. Selectively remove limbs from the perimeter of the canopy, especially those growing close together or beyond the desired size. Also, remove branches with narrow angles of attachment. Branches should be taken back to their point of origin or to laterals that are at least one-third the diameter of the limb being removed.
Trees vary in the amount of thinning they can tolerate without creating ill effects.
An over-thinned tree will respond by producing numerous watersprouts and suckers. Sunscald can occur on thin-barked trees. Never remove more than 25 percent of the total foliage at one time. Heading back - will reduce the overall size of a tree. Cut back to good lateral branches and possible head the tips of the laterals.