Trees must be pruned sometimes to avoid interference with utility 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, ISA Director of Educational Goods and Services. “Topped trees are ugly, and the harmful effects usually endure for the life of the tree.”
The destructive effects of topping include:
“Starved” trees – Topping often removes 50 to 100 percent of the leaf-bearing crown, robbing the tree of food-creating leaves.
Creation of weak shoots – As a defense mechanism, a tree will quickly grow food-producing shoots (up to 20 feet in one year) that are weak and prone to breaking, resulting in a more hazardous tree.
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.
“Sunburned” trees – 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.
Poor aesthetics – 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.
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.