Severe heading causes decay and sprout production from the cut ends, resulting in a potentially hazardous situation once the sprouts become large and heavy. Topping or heading back is not a recommended pruning method. If a tree has been topped previously and has sprouted vigorously, crown restoration can improve its structure and appearance. One to three sprouts on main branch stubs are selected to become permanent branches and to form a more natural appearing crown. Selected vigorous sprouts may need to be thinned to a lateral to control length growth and ensure adequate attachment for the size of the sprout.
Restoration usually requires several prunings over a number of years.
Trees in urban and landscape setting s may need to have lower limbs removed. Crown raising, or elevating, removes the lower branches of a tree in order to provide clearance for buildings, vehicles, pedestrians, and vistas. Excessive removal of lower limbs should be avoided so that the development of trunk taper is not affected and structural stability is maintained. Regardless of the pruning techniques used, avoid removing more than one third of the foliage in one season. Excessive thinning or crown reduction can stress a tree because the reduced photosynthetic capacity.