US TREE SERVICE
Reasons For Pruning

include safety, health, and aesthetics. In addition, pruning can
be used to stimulate fruit production and increase the value of
timber. Pruning for safety (Fig. 1A) involves removing
branches that could fall and cause injury or property damage,
trimming branches that interfere with lines of sight on streets or
driveways, and removing branches that grow into utility lines.
Safety pruning can be largely avoided by carefully choosing
and have strength and form characteristics that are suited to
the site.

Pruning for health (Fig. 1B) involves removing diseased or
insect-infested wood, thinning the crown to increase airflow
and reduce some pest problems, and removing crossing and
rubbing branches. Pruning can best be used to encourage
trees to develop a strong structure and reduce the likelihood of
damage during severe weather. Removing broken or damaged
limbs encourages wound closure.

Pruning for aesthetics (Fig. 1C) involves enhancing the natural
form and character of trees or stimulating flower production.
Pruning for form can be especially important on open-grown
trees that do very little self-pruning.  
Introduction
The objective of pruning is to produce strong, healthy, attractive plants. By understanding
achieved.
poorly attached may be broken off by wind and accumulation of snow and ice. Branches
removed by such natural forces often result in large, ragged wounds that rarely seal. Pruning as
a cultural practice can be used to supplement or replace these natural processes and increase
the strength and longevity of plants.

Trees have many forms, but the most common types are pyramidal (excurrent) or spherical
(decurrent ). Trees with pyramidal crowns, e.g., most conifers, have a strong central stem and
lateral branches that are more or less horizontal and do not compete with the central stem for
dominance. Trees with spherical crowns, e.g., most hardwoods, have many lateral branches that
may compete for dominance.

To reduce the need for pruning it is best to consider a tree's natural form. It is very difficult to
impose an unnatural form on a tree without a commitment to constant maintenance.

Pollarding and topiary are extreme examples of pruning to create a desired, unnatural effect.
Pollarding is the practice of pruning trees annually to remove all new growth. The following year,
a profusion of new branches is produced at the ends of the branches. Topiary involves pruning
trees and shrubs into geometric or animal shapes. Both pollarding and topiary are specialized
applications that involve pruning to change the natural form of trees. As topiary demonstrates,
given enough care and attention, plants can be pruned into nearly any form. Yet just as proper
pruning can enhance the form or character of plants, improper pruning can destroy it.

Topping and tipping (Fig. 7A, 7B) are pruning
reduce the size or height of the crown of a tree, but
Topping, the pruning of large upright branches
between nodes, is sometimes done to reduce the
height of a tree (Fig. 7A). Tipping is the practice of
cutting lateral branches between nodes (Fig. 7B) to
reduce crown width.

These practices invariably result in the
development of epicormic sprouts, or in the death
of the cut branch back to the next lateral branch
below. These epicormic sprouts are weakly
attached to the stem and eventually will be
supported by a decaying branch.

Improper pruning cuts cause unnecessary injury
and bark ripping (Fig. 7C). Flush cuts injure stem
tissues and can result in decay (Fig. 7D). Stub cuts
delay wound closure and can provide entry to
canker fungi that kill the cambium, delaying or
preventing woundwood formation (Fig. 7E).