Topping is perhaps the most harmful tree pruning practice known. Yet, despite more than 25 years of literature and research explaining its harmful effects, topping remains a common practice.
Topping is the indiscriminate cutting of tree branches to stubs or lateral branches that are not large enough to assume the terminal role. Topping a tree consists of removing 50-100% of the tree canopy (top of the tree). This is an extremely negative practice as it causes weak branching structure and in some cases death of a tree. Since at least 50% of the canopy is being pruned out, the tree needs to compensate for the lost leaves. The tree will rapidly produce shoots that grow right below the pruned section. Since these shoots are formed quickly and profusely, the attachment is not strong. In some cases, depending on tree species, shoots formed can grow 20 feet in one year!!
The wound left from topping can become a hazard of its own because of potential decay/rot issues. Since there are so many large stubs left behind from topping, the tree is not likely able to callus over all of the open wounds. These wounds leave an open path for insects, diseases, and decay to form in the tree. Branch failure is prone to happen due to the added weight from the shoots growing off of a weakening branch stub.
The bark of the topped tree can also be affected. When 50% or more of the leaves are lost during topping, trees can actually get sunburned due to the loss of shade. This damages the inner tissues of the tree causing the bark to split and cankers to form. These cankers ultimately destroy a tree by causing loss of structural integrity.
There are times when size and shape of a tree need to be controlled. With care and skill, this can be accomplished without marring the tree’s beauty and usefulness. Responsible pruning even contributes to the health and safety of a tree. Tree Topping, or Dehorning, is strictly prohibited by the Bismarck Forestry Division Arboricultural Specifications and Standards of Practice. Topping is detrimental to the health and structural integrity of the tree. View a list of Bismarck's Licensed Commercial Arborists below.