Topping trees results in large areas of decay and fast-growing, weak, and unattractive watersprouts.
What is Topping?
Ever notice trees in your community whose branches have been cut to stubs, causing them to look like sheared shrubs? These trees have been improperly topped. If you want healthy and safe trees, these examples of senseless destruction may provoke anger and disgust.
Topping is the indiscriminate and drastic cutting of a tree branch or branches. It has been referred to as heading, stubbing, tipping, lopping, rounding-over, and dehorning. No matter what the name, topping disfigures trees and is detrimental to tree structure, health, and value.
Trees are topped because they grow too large for the places where they were planted, or people become afraid of their large size. Trees are also topped because proper tree pruning methods are not used.
Topping Hurts a Tree in Many Ways
In the most severe cases, topping can lead to the death of a tree.
Topping causes the quick growth of dense, weak, upright branches called watersprouts. Sprouts caused by topping are often weakly attached. They grow so rapidly that a tree can regain its original height in a short time with a dense and unwieldy crown.
Decline in health
Topping removes a tree's food production factory (leaves) and food stored in limbs that are cut. Topping also causes a tree to use valuable food stored in the trunk and roots to regrow limbs and branches. Topping redistributes the use of energy and has a substantial impact on the physiology of a tree. Although debated, topping also can place a tree under stress and affect its tolerance for further injury.
Topping replaces a tree's natural form and beauty with unsightly branch stubs, large wounds, broomlike branch growth, and unhealthy branches.
Because of the negative impacts on appearance, structure, and health, topping can reduce the value of a large ornamental tree by thousands of dollars.
Insects and disease
The drastic removal of limbs by topping exposes remaining limbs to sunshine. This sudden exposure to light and heat can kill or damage a tree's living tissue (the bark and cambium) and is called sunscald. Trees have difficulty protecting themselves from sunscald and the large wounds that result from topping. These sunscald wounds are highly vulnerable to insect invasion and the spores and actions of decay fungi.
How to Prevent Topping
Plant the right tree in the right place
Plant tree species that fit and will thrive in the places where they are planted. Don't plant large trees such as oak, tulip poplar, and sycamore under power lines, in small tree lawns, in sidewalk cutouts, or close to buildings or signs.
Buy quality nursery stock
To assure success when planting landscape trees, it is important to start with a healthy plant that has good structural form. Characteristics that are important to consider when purchasing nursery stock can be found in the American Standards for Nursery Stock, available from the American Association of Nurserymen, 202-789-2900.
Prune young trees
The most important time to prune trees is in the first 5 to 10 years of their life. Proper pruning of young trees promotes correct development of structure, saves money by removing branches when they are small, and keeps pruning wounds small.
All tree pruning should be performed in accordance with current International Society of Arboriculture tree maintenance standards. Insist that thinning cuts and natural target pruning techniques are used.
Proper pruning enhances and protects the natural shape of a tree.
Proper utility clearance
Because of the vigorous growth of sprouts, topping makes utility line clearance more difficult, frequent, and expensive. Most utilities use an arboriculturally correct method called directional pruning instead of topping. Directional pruning directs subsequent growth away from wires and leaves no branch stubs.
When required because of obstructions, a tree's height should be reduced using thinning cuts.
Hire a qualified arborist
Although tree topping may cost less and take less time, why pay for an inferior service? Hire a qualified arborist, preferably a certified arborist, who knows about proper and safe tree care techniques. Do not blindly accept the lowest price. In tree work, the old adage "you get what you pay for" is usually true. Ask for customer references and proof of liability insurance and worker's compensation insurance.
Gather good information
For more information on tree care and management, contact the Penn State Extension Urban Forestry Program at 814-863-7941, the Pennsylvania Urban and Community Forestry Council at 717-783-0385, the International Society of Arboriculture at 217-355-9411, the National Arborist Association at 603-673-3311, the National Arbor Day Foundation at 402-474-5655, or your local electric utility arborist.
Thanks to the International Society of Arboriculture and the National Arbor Day Foundation for information and illustrations used in this fact sheet.
Produced by William Elmendorf, assistant professor of urban and community forestry, and Henry Gerhold, professor emeritus of forest genetics
This fact sheet was prepared by Penn State with guidance from the Pennsylvania Urban and Community Forestry Council and support from the Pennsylvania DCNR Bureau of Forestry. For more information, contact the Pennsylvania Urban and Community Forestry Program, The Pennsylvania State University, 334 Forest Resources Building, University Park, PA 16802; 814-863-7941.