Don't Dress Tree Wounds
gardeners have experienced that awful moment when the lawn mower or
weed whacker accidentally comes in contact with the bark of a valued
tree in the landscape and a wound is created.
No matter how careful you are, accidents happen, and then
you’re left wondering what you can do to help the tree repair
this wound. In most cases, the answer is to let the tree repair the
wound on its own.
|Upon being wounded,
trees begin a natural process of callusing over the
wounded area with new bark and wood. In the spring, when trees are
growing vigorously, this process will naturally occur quickly. During
other times of the year when growth is not as vigorous, try to keep
wounded trees growing as vigorously as possible by fertilizing and
On some trees,
a wound made during the active growing season may attract insects and
pass on pathogens. Wounds on oaks and elms, for instance, may attract
borers and beetles that are carriers of diseases such as Dutch elm
disease and oak wilt.
such cases, a petroleum-based tree wound dressing may be applied to
cover the freshly cut wood in order to inhibit decay or insect
infestation, but its effectiveness is debatable. Researchers at
Washington State University have found that wound dressings
do not prevent entrance of decay organisms or stop rot from
do, on the other hand, seal in moisture and decay, and
sometimes serve as a food source for pathogens, prevent wound
wood from forming, inhibit compartmentalization, and eventually crack,
exposing the tree to pathogens.
pruning a disease-prone species while insects or fungi are active (that
is, during the warmer times of the year), a light coating of an
insecticide or fungicide may be warranted. Otherwise,
avoiding wounds is the best practice.
Mulch around trees and shrubs to avoid mowers and weed whackers getting
close to trees, and prune during the dormant season when insects and
pathogens are not active.
Source: Candice Miller,
University of Illinois Extension
wounds and diseases, their prevention and treatment
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