Topping
Trees Is Bad News
Proper
Pruning to Promote Healing
Topping is an
unacceptable pruning practice that can lead to stress, decay and hazardous
conditions in trees. Even so, hundreds of trees are topped, headed, or rounded
over every year in the Baltimore areas because a homeowner may feel that a tree
has become too large. Topping occurs when tree branches are cut back leaving
stubs or lateral branches that are not large enough to assume normal growth.
Crown reduction by topping does not work, and can injure a tree in several ways.
Topping reduces the leaf-bearing crown of a tree by 50-100%, thereby removing
most or all of the food-producing capabilities it may have. New buds become
active and rapidly growing shoots develop at each cut to make up for the sudden
loss of leaves. This will stress the tree by depleting any stored food reserves
and making it vulnerable to insect and disease attacks. The sudden exposure of
the inner branches and trunk to high levels of sunlight can also lead to injury
of the wood tissues. Proper pruning would remove no more than 25-30% of the
leaf-bearing crown.
Large wounds take longer to close over, and stubs will decay when a topping cut
is made. Proper pruning cuts are made just beyond the branch collar near the
branch's point of attachment. Such pruning cuts are usually smaller and less
numerous, and also heal over more readily. Decay resulting from improper topping
cuts is likely to spread through the remaining wood.
The shoots that develop below a topping are only weakly attached to the
outermost wood layers, unlike normal branches that are anchored deeper in the
wood tissues. These shoots, which can grow 10-20 feet per year, are much more
subject to breaking. The tree becomes a hazard and a potential liability to the
tree's owner. Although hazardous conditions could take some time to develop, the
owner may still be held liable even years after the topping occurred.
Topped trees often require pruning again in only a few years to remove shoots
and decayed areas. The trees appear disfigured and lose their natural graceful
form. Properly pruned and maintained trees leave little or no indication that
pruning even occurred, and can add 10-20% to property values.
If a tree's crown must be reduced in size or thinned, proper pruning cuts will
avoid the problems mentioned above. Never should more than 1/3 of the crown be
removed. Selected branches should be removed back to their point of attachment,
or to a lateral branch that is at least 1/3 the diameter of the branch being
removed without leaving stubs.
Tree professionals working in Maryland must be licensed by the Department of
Natural Resources as Tree Care Experts. They must demonstrate knowledge of
proper tree care practices and carry an minimum amount of liability insurance.
Always ask for the tree expert license number, proof of current insurance, and
references. A written contract of work to be performed, as well as a
receipt, is suggested also.
For more detailed
information http://www2.champaign.isa-arbor.com/consumer/topping.html
For
more information, contact the
Maryland DNR Forest
Service at 410-665-5820 or 410-836-4551.
(Information
on topping adapted from the International Society of Arboriculture)
This page was last updated on 04/11/01
