Pruning is an important component of maintaining a tree health and growth. Pruning accomplishes several objectives: controlling size, encouraging healthy growth, improving quality of growth, and training to achieve a specific look or function. The properly-pruned tree will typically grow symmetrically, produce fully-foliaged branches, have crossed or dead branches removed, display cleanly, and enjoy light and air access throughout the crown.
There are four overarching purposes for pruning trees:
- Controlling size
- Encouraging healthy growth
- Improving quality of growth
- Training of growth habit
Whether you’re a Texas home-owner with two trees, the manager of a commercial walnut grove in California, or a superintendent of a South Florida landscaping company, the maintenance of the trees in your care is a significant responsibility.
In this article, we discuss the reasons why tree-pruning is important and what pruning accomplishes.
Pruning restricts/controls size
Pruning to control overall size is a common practice in urban areas or in settings where trees need to remain at a certain height or girth or within the confines of a container. Root pruning is a technique that can also be performed on plants in containers.
Pruning to restrict size may also be important for the safety and protection of a property and the people on it. A dead branch extending over a lawn should be removed before it breaks and falls on someone walking underneath. A limb growing against a house or roof should be pruned back to keep it from damaging structural surfaces.
Pruning Stimulates Growth
Pruning a tree encourages new growth. A leggy branch (one that’s mostly branch with little foliage) can be pruned back to result in tips that produces multiple buds.
Removing dying, ill or diseased branches redirects water and nutrients to healthy branches, resulting in more vigorous growth.
Pruning Improves Tree Health
A tree becomes healthier when diseased, susceptible or redundant parts are pruned out. These include crossed branches, water sprouts, and suckers.
When tree branches cross, they rub together and the bark becomes damaged. The damage can lead to decay which introduces illness to the rest of the tree. Crossed branches should be addressed by removing one of the branches.
Water sprouts are shoots that grow straight up, usually from latent buds. They sometimes grow from areas of damage or pruning. Water sprouts, sometimes called water shoots, are generally not as strong as normal branches. Their lack of strength and their vertical growth habit are reasons why the tree is healthier and looks better when these sprouts are removed.
Suckers typically grow up or out from previously pruned areas. They are redundant growths that detract from the appearance of the tree and hijack nutrients and water. Removing suckers when they are young is the best pruning protocol.
Pruning to improve the health and growth of large trees is a task best left to professional tree trimmers or a licensed arborist. Commonly performed procedures on large trees include crown thinning, raising, reduction, and cleaning.
Crown thinning is the removal of branches in the crown to allow for more light and air to pass through that part of the tree. Crown raising is removing low branches to open more space between the bottom of the crown and the ground, creating headroom over lawns, sidewalks, etc. Crown cleaning is the removal of branches–usually dead, dying or diseased ones. The pruning of large branches at the top of a tree is called crown reduction. This is done to manage the height of a tree and, especially in mature trees, should be done as minimally as possible.
Pruning Trains Growth Habit
For most landscapes, letting trees grow into their natural form and shape is the best practice. In some cases, however, trees are shaped for special effects, such as boxwood topiaries or an espaliered apple or pear tree.
Topiary is the horticultural practice of target-pruning a tree to produce a clearly defined shape. This can be a geometric shape or a whimsical shape such as an animal or a cartoon character.
Espalier is the practice of pruning and training a fruit tree to grow along a wall or a fence. This makes good use of a vertical plane space and produces fruit that is easy to pick. Espaliered trees can also be evergreen or deciduous, and their purpose can be ornamental.
Espaliered trees can be trained and pruned so that the overall shape represents a fan, a candelabra, a lattice, a “Y,” or a cordon, which is when the trunk goes straight up and the branches go straight out to the sides, evenly spaced apart and in opposing pairs.
Summing It Up
Tree trimming is both an art and a science. Having a good eye for balance and symmetry is important when pruning trees to achieve a certain shape. Knowledge of safe pruning techniques is important so that trees are not damaged.