The practice of topping (also referred to as stubbing, dehorning, pollarding, heading, and by several other euphemisms) has risen to crisis proportions nationally over the past two decade. Topping has become the urban forest’s major threat, dramatically shortening the lifespan of trees and creating hazards trees in high-traffic areas.
Contrary to popular belief, topping won't work to keep trees small. With proper care, a tree will grow as tall as it is specifically genetically designed to grow. After a deciduous tree is topped, however, its growth rate increases. It grows back rapidly in an attempt to replace its missing leaf area, as it needs all of its leaves to manufacture food for the trunk and roots. The growth won’t slow down until it reaches the same size it was before it was topped. It takes, at maximum, a few years before your tree returns to near its original size.
Topping destroys the natural shape; hence winter silhouette of a tree. After a tree is topped, hormones stimulate it to grow an ugly mass of straight suckers to replace the old limb destroying its natural shape. Consequently, many topped trees are considered a total loss. In some parts of the United States, these trees are considered illegal and are even completely removed.
Many people top their trees because they think it will make them safer. Topping creates hazardous trees. New limbs made from the sucker or shoot regrowth after topping are weakly attached to the tree. A regrown limb never has the structural integrity of the original limb. These are the limbs that fall on cars or houses below as they easily break in wind or snow storms even many years later when they are large and heavy.
To avoid compromising tree care resulting in disaster, the Arboriculture Industry strongly urges the public to hire only ISA certified arborists to prune trees.