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Don't Top Trees!
Topping is perhaps the most harmful tree pruning practice
known. Yet despite more than 25 years of literature and seminars explaining its
harmful effects, topping remains a common practice. This brochure explains why
topping is not an acceptable pruning technique and offers some better
alternatives.
| What Is Topping?
Topping is the indiscriminate cutting back of tree
branches to stubs or lateral branches that are not large enough to assume
the terminal role. Other names for topping include "heading", "tipping",
"hat-racking", and "rounding over". |
The most common reason given for topping is to reduce the
size of a tree. Often homeowners feel that their trees have become too large
for their property. People fear that tall trees may pose a hazard. Topping,
however, is not a viable method of height reduction, and certainly does not
reduce the hazard. In fact, topping will make a tree more hazardous in the long
term.
| Topping Stresses Trees
Topping often removes 50-100% of the leaf-bearing
crown of a tree. Since the leaves are the "food factories" of a tree, this
can temporarily "starve" a tree. The severity of the pruning triggers a
sort of survival mechanism. The tree activates latent buds, forcing the
rapid growth of multiple shoots below each cut. The tree needs to put out a
new crop of leaves as soon as possible. If a tree does not have the stored
energy reserves to do this, it will be seriously weakened and may die. A
stressed tree is more vulnerable to insect and disease infestations. Large,
open pruning wounds expose the sapwood and heartwood to attack. The tree
may lack sufficient energy to chemically "defend" the wounds against
invasion. Some insects are actually attracted to stressed trees by chemical
signals. |
| Topping Causes Decay
The preferred location to make a pruning cut is just
beyond the branch collar at the branch's point of attachment. The tree is
biologically equipped to close such a wound provided the tree is healthy
enough and the wound is not too large. Cuts made along a limb, between
lateral branches, create stubs with wounds that the tree may not be able to
close. The exposed wood tissues begin to decay. Normally a tree will "wall
off" or compartmentalize the decaying tissues. But few trees can defend the
multiple severe wounds caused by topping. The decay organisms are given a
free path to move down through the branches. |
| Topping Creates Hazards
The survival mechanism that causes a tree to produce
multiple shoots below each topping cut comes at great expense to the tree.
These shoots develop from buds near the surface of the old branches. Unlike
normal branches that develop in a "socket" of overlapping wood tissues,
these new shoots are only anchored in the outermost layers of the parent
branches. The new shoots grow very quickly, as much as 20 feet in one year,
in some species. Unfortunately, the shoots are very prone to breaking,
especially during windy conditions. The irony is that while the goal was to
reduce the tree's height to make it safer, it has been made more hazardous
than before. |
| Topping Makes Trees Ugly
The natural branching structure of a tree is a
biological wonder. Trees form a variety of shapes and growth habits, all
with the same goal of presenting their leaves to the sun. Topping removes
the ends of the branches, often leaving ugly stubs. Topping destroys the
natural form of a tree. Without the leaves (up to six months of the year in
temperate climates) a topped tree appears disfigured and mutilated. With
the leaves, it is a dense ball of foliage, lacking its simple grace. A tree
that has been topped can never fully regain its natural form. |
| Topping Is Expensive
The cost of topping a tree is not limited to what the
perpetrator is paid. If the tree survives, it will require pruning again
within a few years. It will either need to be reduced again, or storm
damage will have to be cleaned up. If the tree dies it will have to be
removed. Topping is a high maintenance pruning practice. There are some
hidden costs of topping. One is the reduction in property value. Healthy,
well maintained trees can add 10-20% to the value of a property.
Disfigured, topped trees are considered an impending expense. Another
potential cost of topped trees is the potential liability. Topped trees are
prone to breaking and can be hazardous. Since topping is considered to be
an unacceptable pruning practice, any damage caused by branch failure of a
topped tree may lead to a finding of negligence in a court of law. |
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