Care, Pruning and Tree Cutting Tips
is the most common tree maintenance procedure. Although forest
trees grow quite well with only nature's pruning, landscape
trees require a higher level of care to maintain their safety
and aesthetics. Pruning should be done with an understanding of
how the tree responds to each cut. Improper pruning can cause
damage that will last for the life of the tree, or worse,
shorten the tree's life.
Because each cut
has the potential to change the growth of the tree, no branch
should be removed without a reason. Common reasons for pruning
are to remove dead branches, to remove crowded or rubbing limbs,
and to eliminate hazards. Trees may also be pruned to increase
light and air penetration to the inside of the trees crown or
to the landscape below. In most cases, mature trees are pruned
as a corrective or preventive measure.
does not necessarily improve the health of a tree. Trees produce
a dense crown of leaves to manufacture the sugar used as energy
for growth and development. Removal of foliage through pruning
can reduce growth and stored energy reserves. Heavy pruning can
be a significant health stress for the tree.
Yet if people and
trees are to coexist in an urban or suburban environment, then
we sometimes have to modify the trees. City environments do not
mimic natural forest conditions. Safety is a major concern.
Also, we want trees to complement other landscape plantings and
lawns. Proper pruning, with an understanding of tree biology,
can maintain good tree health and structure while enhancing the
aesthetic and economic values of our landscapes.
When to Prune
pruning to remove weak, diseased, or dead limbs can be
accomplished at any time during the year with little effect on
the tree. As a rule, growth is maximized and wound closure is
fastest if pruning takes place before the spring growth flush.
Some trees, such as maples and birches, tend to "bleed" if
pruned early in the spring. It may be unsightly, but it is of
little consequence to the tree.
A few tree
diseases, such as oak wilt, can be spread when pruning wounds
allow spores access into the tree. Susceptible trees should not
be pruned during active transmission periods.
Heavy pruning just
after the spring growth flush should be avoided. At that time,
trees have just expended a great deal of energy to produce
foliage and early shoot growth. Removal of a large percentage of
foliage at that time can stress the tree.
should be made just outside the branch collar. The branch collar
contains trunk or parent branch tissue and should not be damaged
or removed. If the trunk collar has grown out on a dead limb to
be removed, make the cut just beyond the collar. Do not cut the
If a large limb is
to be removed, its weight should first be reduced. This is done
by making an undercut about 12 to 18 inches from the limbs
point of attachment. Make a second cut from the top, directly
above or a few inches farther out on the limb. Doing so removes
the limb, leaving the 12 to 18-inch stub. Remove the stub by
cutting back to the branch collar. This technique reduces the
possibility of tearing the bark.
Specific types of
pruning may be necessary to maintain a mature tree in a healthy,
safe, and attractive condition.
the removal of dead, dying, diseased, crowded, weakly attached,
and low-vigor branches from the crown of a tree.
the selective removal of branches to increase light penetration
and air movement through the crown. Thinning opens the foliage
of a tree, reduces weight on heavy limbs, and helps retain the
trees natural shape.
removes the lower branches from a tree in order to provide
clearance for buildings, vehicles, pedestrians, and vistas.
reduces the size of a tree, often for clearance for utility
lines. Reducing the height or spread of a tree is best
accomplished by pruning back the leaders and branch terminals to
lateral branches that are large enough to assume the terminal
roles (at least one-third the diameter of the cut stem).
Compared to topping, reduction helps maintain the form and
structural integrity of the tree.
Should Be Pruned?
The amount of live
tissue that should be removed depends on the tree size, species,
and age, as well as the pruning objectives. Younger trees
tolerate the removal of a higher percentage of living tissue
better than mature trees do. An important principle to remember
is that a tree can recover from several small pruning wounds
faster than from one large wound.
A common mistake
is to remove too much inner foliage and small branches. It is
important to maintain an even distribution of foliage along
large limbs and in the lower portion of the crown. Over thinning
reduces the trees sugar production capacity and can create
tip-heavy limbs that are prone to failure.
should require little routine pruning. A widely accepted rule of
thumb is never to remove more than one-quarter of a trees
leaf-bearing crown. In a mature tree, pruning even that much
could have negative effects. Removing even a single,
large-diameter limb can create a wound that the tree may not be
able to close. The older and larger a tree becomes, the less
energy it has in reserve to close wounds and defend against
decay or insect attack. The pruning of large mature trees is
usually limited to removal of dead or potentially hazardous
were once thought to accelerate wound closure, protect against
insects and diseases, and reduce decay. However, research has
shown that dressings do not reduce decay or speed closure and
rarely prevent insect or disease infestations. Most experts
recommend that wound dressings not be used. If a dressing must
be used for cosmetic purposes, then only a thin coating of a
nontoxic material should be applied.
trees can be dangerous. If pruning involves working above the
ground or using power equipment, it is best to hire a
professional arborist. An arborist can determine the type of
pruning necessary to improve the health, appearance, and safety
of your trees. A professional arborist can provide the services
of a trained crew, with all of the required safety equipment and
There are a
variety of things to look for when selecting an arborist:
- membership in professional
organizations such as the International Society of
Arboriculture (ISA), the Tree Care Industry Association (TCIA),
or the American Society of Consulting Arborists (ASCA)
- certification through
ISA's Certified Arborist program
- proof of insurance
- list of references
hesitate to check)
Avoid using the
services of any tree company that
- advertises topping as a
service provided; knowledgeable arborists know that topping
is harmful to trees and is not an accepted practice
- uses tree climbing spikes to
climb trees that are being pruned; climbing spikes can
damage trees, and their use should be limited to trees that
are being removed
This brochure is
one in a series published by the International Society of
Arboriculture as part of its Consumer Information Program. You
may have additional interest in the following titles currently
in the series:
(c) 1998, 2004 International Society of Arboriculture -
UPDATED JULY 2005
Developed by the
International Society of Arboriculture (ISA), a non-profit
organization supporting tree care research around the world and
is dedicated to the care and preservation of shade and