Pruning 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.
Reasons for Pruning
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 tree’s crown or to the landscape below. In most
cases, mature trees are pruned as a corrective or preventive
Routine thinning 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
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
Most routine 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.
Making Proper Pruning Cuts
Pruning cuts 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 collar.
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 limb’s 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.
Cleaning is the removal of dead, dying, diseased, crowded,
weakly attached, and low-vigor branches from the crown of a
Thinning is 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 tree’s natural shape.
Raising removes the lower branches from a tree in order to
provide clearance for buildings, vehicles, pedestrians, and
Reduction reduces the size of a tree, often for clear- ance for
utility lines. rolex replica uk
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.
How Much 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. replica watches
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.
Overthinning reduces the tree’s sugar production capacity and
can create tip-heavy limbs that are prone to failure.
Mature trees should require little routine pruning. A widely
accepted rule of thumb is never to remove more than one-quarter
of a tree’s leaf-bearing crown. hublot replica sale
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
Wound dressings 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.
Employing a Tree Surgeon
Pruning large trees can be dangerous. If pruning involves
working above the ground or using power equipment, it is best to
hire a professional tree surgeon. A tree surgeont can determine
the type of pruning necessary to improve the health, appearance,
and safety of your trees. See our Tree Surgeon Page for more
information on this aspect of tree maintenance.