By Jeff McMann
Trees play an important part in a landscape environment, often providing the backbone around which backyards are built. They improve the quality of the air we breathe, absorbing, trapping and filtering harmful pollutants. They provide shade around the pool in the summer and shelter in winter. Well-placed trees can reduce noise from neighbours and vehicles, lessen glare and provide shade and shelter from harmful ultraviolet (UV) rays. In addition, trees also provide benefits to landscapers, adding an extra dimension and grandeur to a backyard design.
Despite these benefits, trees are often neglected in a few ways. There are many prevalent misconceptions about trees, even amongst industry professionals, and several persistent myths that can actually perpetuate more harm than good. Pool and landscape professionals must understand how a tree grows, what it needs and how it should be properly maintained. Below are a few of the more common myths associated with trees and their care.
Myth 1: Topping is good for trees
Topping is the drastic removal or cutting back of most of a tree’s large branches. It is often confused with pollarding. Pollarding is a pruning system in which the major limbs of the tree are dramatically cut back. Each following year, the long slender shoots that grow below the cuts are then removed, and a new set of shoots quickly take their place. The tree develops a stubby and knobby appearance, resulting in a dense mass of foliage and branches.
The pollarding process, which has been practiced for many centuries in Europe to maintain trees at a certain height, should begin when a tree is very young. It is a high-maintenance practice; depending on the tree species, annual or biennial pruning is required.
Trees are often topped so they can fit a given area or be maintained in a smaller shape. However, unlike pollarding, topping can be harmful to trees. A proper pruning cut should be made just beyond the branch collar at the branch’s point of attachment. The tree is biologically equipped to close such a wound, provided it is healthy enough and the wound is not too large. Topping, however, creates cuts above the branch collar (the swollen area of trunk tissue that forms around the base of a branch), creating stubs with numerous wounds that may not close. In actuality, it is one of the worst things you can do to a tree. Some incorrect assumptions many professionals make about topping include:
- Topping does not injure the tree;
- Topping ‘invigorates’ a tree; and
- Topped trees add value and beauty to a property.
Topping, in fact, severely injures a tree. Consider the process—by removing most of the leaves and branches, large wounds are left exposed. This leaves the tree susceptible to insect attacks and decay. Very few trees can defend themselves against the multiple severe wounds caused by topping; as a result, exposed tissues begin to decay. Decay organisms are given a free path to move down through the branches. The tree becomes stressed and, consequently, more vulnerable to insect and disease infestations.
In addition, since every tree needs foliage to produce food, a topped tree will try to compensate for the excessive removal of its branches and leaves by exhausting its stored resources to produce new branches. As a result of this quick growth, new branches are weakly attached and more susceptible to breakage and storm damage. A topped tree can become hazardous and cause property damage (e.g. a loose branch falling on to a person or parked car), making it a liability, rather than an asset. Furthermore, the tree can actually grow to be taller than it was before topping was performed.
Ultimately, a topped tree requires more attention in the future than a properly pruned tree (more on that below). It may survive the process, but its lifespan will be significantly reduced. The end result lacks all natural beauty and form, and may actually have a negative impact on a design.