Trees must be pruned sometimes to avoid interference with utility (power and phone) lines, buildings, or parts of the surrounding environment. Whenever pruning to reduce a tree’s size is required, avoid the harmful practice of topping
Topping involves removing all parts of a tree above a certain height with no consideration for its structure or health
. This method is not a viable method of height reduction but only a temporary and ineffective solution that actually makes a tree more hazardous in the long run.
The International Society of Arboriculture (ISA) explains why topping is not an acceptable pruning technique. “Topping is probably the most damaging and detrimental thing a person can do to a tree,”
says Sharon Lilly, Director of Education for ISA. “Topped trees are ugly, and the harmful effects usually endure for the life of the tree.”
The destructive effects of topping include:
Creation of weak shoots- As a defence mechanism, a tree will quickly grow (up to 20 feet/ 6.5 metres in one year) food-producing shoots that are weak and prone to breaking, resulting in a more hazardous tree
Higher maintenance costs
- Trees that have been topped will need pruning more often, or may die and need to be removed. Topped trees are potential liabilities and can reduce property value.
Added stress for the tree
- If a tree does not have enough stored energy it will not be able to produce the chemicals required to defend the multiple wounds from a disease or insect attack.
- The leaves within a tree’s crown absorb sunlight. Without
this protection, branches and trunks are exposed to high levels of light and
heat which can burn the tissues beneath the bark.
- Topping removes the ends of branches often leaving unsightly stubs, and destroying the natural form of the tree. A tree that has been topped can never fully regain its natural form.
– Topping often removes 50-100 percent of the leaf-bearing crown robbing the tree of food-creating leaves.
To help avoid these harmful side effects ISA advises that trees should be pruned according to the American National Standards Institute’s (ANSI) pruning standards.
An ISA Certified Arborist should quote approved ANSI pruning methods to their customers. Beware of a tree service that offers to top your tree; they may not be up to date on the latest pruning methods.
The International Society of Arboriculture (ISA), headquartered in Champaign, Ill., is a nonprofit organization supporting tree care research and education around the world. As part of ISA’s dedication to the care and preservation of shade and ornamental trees, it offers the only internationally-recognized certification program in the industry.
Sonia Abney Garth
International Society of Arboriculture
217-355-9411, ext. 217