The main reasons for pruning ornamental and shade trees include safety, health, and aesthetics. In addition, pruning can be used to stimulate fruit production and increase the value of timber. Pruning for safety 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 species that will not grow beyond the space available to them, and have strength and form characteristics that are suited to the site.
Pruning for health 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. Healthy pruning of trees can create long lasting durable trees.
Pruning for aesthetics 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, and on smaller ornamental trees.
Types of pruning:
Crown Cleaning: a method of pruning to remove dead, rubbing, criss crossing, or interfering branches to develop a healthy growing structure for the tree.
Crown Raising: a method of pruning to provide clearance for pedestrians, vehicles, buildings, lines of sight, increased light penetration and vistas by removing lower branches.
Crown Reduction Pruning: a method of pruning used to reduce the height of a tree. Branches are cut back to laterals that are approximately one-third the diameter of the limb being removed.
Crown Thinning: a method of pruning to increase light penetration and air movement through the crown of a tree by selective removal of branches.