It’s easy to think the job is done once your new landscape trees are planted in the ground. However, a few more things still need to happen to provide the best chance of a long-lived healthy tree. The best thing you can do is provide some structural pruning or “training” of the young tree to force a well-developed trunk and branch structure. This will provide less opportunity for disease and damage as the tree ages. Structural tree pruning for newly planted landscape trees is an investment sure to pay off in the long run.
This article aims to inform you how to train young, newly planted trees through proper pruning to promote good branch structure resulting in long-lived, serviceable, and healthy trees. In addition, structural pruning reduces the potential for structural failure at maturity and results in less maintenance as the trees mature.
If you would like professional guidance or recommendations, please feel free to reach out to us.
This article used Best Management Practices: Tree Pruning by Edward F. Gilman and Sharon J. Lilly as a reference. We encourage you to check out that publication if you want to learn more.
Structural Pruning Definition
Structural pruning is the removal of live branches and stems to influence the orientation, spacing, growth rate, strength of attachment, and ultimate size of branches and stems. It is used on young and medium-aged trees to help engineer a sustainable trunk and branch arrangement. If young trees are pruned to promote good structure, they likely will remain serviceable in the landscape for more years than trees that have not been structurally pruned. Waiting until the tree grows larger makes structural pruning much more difficult and detrimental to the tree.
Professional Help:
Due to safety reasons, we recommend that most prunings be completed by an ISA Certified Arborist in accordance with TCIA A300 Part 1 and ANSI Z133.1 Safety Standards. Tree care and pruning are extremely dangerous and result in thousands of injuries every year to homeowners and DIYers.
Depending upon your skill level, equipment, size of the trees, and level of comfort, you may be able to do some of these basic pruning techniques on smaller trees as long as safety and proper techniques are emphasized.
If you go with a local tree care company, ask them to provide a copy of their ISA Certified Arborist license. You can find arborists on the ISA website as well.
Structural Pruning Process:
The training process should be spread out over many years. Never remove more than 25% of the canopy in any one year.
Prune trees each year for the first three years, then every five years to age 30 according to the training steps below.
As you read through the structural pruning steps, it may be helpful to refer back to the diagram below which identifies the leader, scaffold, and lateral branches of a tree.
Five simple steps to properly train young trees:
Step 1: Clean the canopy by removing all dead, broken, diseased, damaged, and dying branches. Complete this step at every pruning occurrence.
Step 2: Choose and develop a dominant central leader. There should only be one leader which is usually the strongest vertical stem.
To select a leader and develop the leader, follow this process:
- Choose the one stem that will make the best leader.
- Identify which stems and branches are competing with this leader.
- Decide how much to shorten these competing stems.
- Prevent branches from growing larger than half the trunk diameter by regular pruning.
Multiple prunings over time (for example 15 to 25 years) are usually required to develop a dominant leader. Competing stems and branches are subordinated (reduced in length) or removed. Subordination is usually preferred over removal, especially if the problem stem or branches are larger than half the trunk diameter. Subordination may cause less trunk decay than removal. If necessary, the offending stem(s) can always be removed later.
Step 3
Select and establish the lowest permanent branch if the tree is old enough. The lowest permanent branch should be less than half the diameter of the trunk at the point of attachment. Establish the lowest permanent branch by shortening vigorous branches below it and any lower branches that grow up into the crown. This procedure may not be possible on a young tree if all branches are below the best position for the lowest permanent branch. The height of the lowest limb is determined by the location and intended function of the tree. For example, a tree along a roadway may require the lowest permanent branch to be 15 feet above grade.
Step 4
Select and establish scaffold branches. This is done by subordinating or removing competing stems or branches. Scaffold branches are located above the lowest permanent branch and provide the base on which to build the permanent crown. These branches should be selected for good attachment, appropriate size, and spacing in relation to other branches. Scaffold branches shall be free of serious defects such as included bark and cracks, should be among the largest on the tree, and should be appropriately spaced apart. Vertical spacing should be at least 18 inches for large maturing trees and about 12 inches for smaller trees. They should also be radially spaced around the tree.
Step 5
Selection and subordination of temporary branches below the lowest permanent branch and among the scaffold branches. The temporary branches should be retained temporarily because they help provide energy back to the trunk, contribute to trunk taper development, and provide shade to young trunk tissues. As the tree matures, these branches may be removed as necessary.
Closing Thoughts
Once you know the steps, structural tree pruning for newly planted landscape trees is relatively easy and will pay off in the long run. It’s much easier to deal with young trees when they can heal and grow quickly. As the saying goes, “You can’t train an old dog new tricks,” old trees are hard to train and fix. So train your trees!