Tree Trimming: Avoiding Common Pruning Mistakes

Most Devastating Mistake: Tree Topping

Tree topping is the most dangerous form of trimming that is attempted by homeowners (and many other non-professionals). Topping destroys a tree by cutting off a major portion of the trunk or larger branches, destroying the tree’s natural canopy structure entirely. Although the uninformed service provider will tell you that tree topping “is the way” to shorten your trees quickly and cheaply, tree topping damages trees severely and ultimately puts your home and family in danger long-term.

When a homeowner tops a tree, the tree responds by producing clusters of very weak, poorly attached water sprouts growing rapidly from the cut sites. As these emergency shoots do not have the same structural characteristics as normal branches, the water sprouts frequently break during strong winds and/or storms, creating future dangers to homes.

Why Homeowners Are Topped

Homeowners ask to have trees topped because they think that it is the fastest way to decrease the size of their trees, and because they usually expect to pay less money. Unfortunately, the homeowner will find that a tree that has been topped will need to be trimmed again (even more frequently) than a tree that was pruned properly, since the water sprouts produced by the tree to compensate for the lost branches must be continuously removed to regain some control of the tree.

Ultimately, topping the tree results in long-term cost to the homeowner through faster deterioration of the tree, increased susceptibility of the tree to pests, and increased chance of failure of the tree, which would result in an emergency removal of the tree. The trained arborist understands the damage caused by topping and offers alternative methods of crown reduction.

Removing too much of the canopy at once: Over-Pruning

Exuberant homeowners frequently make the mistake of removing too much foliage at one time. Leaves are necessary for the process of photosynthesis and the energy required by trees. Therefore, excessive pruning causes significant stress to the tree and makes it difficult for the tree to recover from the wounds caused by cutting.

In addition to the above-mentioned information, there are rules regarding the amount of pruning allowed per season. In general, no more than 25% of a tree’s canopy may be pruned in any one season. If you exceed this percentage, you will be stressing the tree and putting it at greater risk of developing diseases, attracting pests, and being affected by environmental factors that healthier trees can withstand.

Identifying Signs of Over-Pruning

If you have over-pruned a tree, you will see several warning signs. Some include:

• Sparse foliage
• Weak new growth
• Increased susceptibility to sun-scald
• Slowed recovery from seasonal changes

These symptoms will take time to develop and are usually not apparent immediately; therefore, many homeowners do not realize the damage until it is too late to correct it.

Trees that have been subjected to over-pruning become targets for pests and diseases that seek out the weakened specimens. A trained arborist will evaluate your trees and recommend the proper amount of pruning based on the tree species, age, and overall health.

Mistakes Due to Improper Timing

Another common mistake that homeowners make when attempting to trim trees without professional help is improper timing. As previously stated, different species of trees require specific timing to minimize stress and allow the tree to react to the pruning. However, the timing for each species differs greatly depending on the flowering habits and the growth patterns of the tree.

Pruning a tree in late summer is particularly detrimental because it encourages new growth that does not have enough time to harden off prior to the onset of winter. Thus, this new growth is highly susceptible to cold-weather damage and potentially could kill entire sections of the tree or compromise the entire tree.

Timing Specific to Tree Species

Trees that bloom in the spring, such as dogwood and magnolia, should be pruned immediately after they finish blooming to avoid removing the flower bud for next year’s bloom. Pruning a tree that blooms in the spring during the winter months will eliminate the spring blooms for the following year and will also deplete the tree’s stored energy reserves.

Trees that “bleed,” or lose a lot of sap, such as maple, birch, and walnut, should be pruned in late summer or early fall to minimize the amount of sap that is lost. While the bleeding itself is not damaging to the tree, it may attract pests and cause stains on trunks and nearby surfaces.

Improper Cutting Techniques

Many homeowners attempt to prune trees without knowing the proper cutting techniques, thus creating wounds that will not heal well and will be susceptible to disease. One of the most important aspects of cutting trees is identifying and protecting the branch collar, a special group of cells located where a branch meets the trunk of the tree. This group of cells allows the tree to compartmentalize and heal the wound created by the pruning.

Flush cuts that remove the branch collar eliminate the tree’s ability to defend itself against decaying organisms. Conversely, stub cuts that leave too much branch material provide entry points for pathogens and inhibit the development of a callus to seal the wound.

Three-Cut Method for Larger Branches

To safely remove branches that are larger than 1.5 inches in diameter, the three-cut method should be used to prevent bark tearing that can cause damage to the trunk of the tree. The first cut is an undercut that is partway into the branch; the second cut is a top cut to remove the weight of the branch; and the third cut is to remove the stub just outside of the branch collar.

The use of dull tools further complicates cutting problems by causing the wound to be jagged and slow to heal, and providing many opportunities for disease to enter the tree. Professional arborists know which cutting techniques to use for different branch sizes and locations and maintain sharp, properly-sized tools for safe and effective pruning.

Lion’s Tail and Interior Stripping

Lion’s tail refers to the removal of all interior branches and foliage while allowing only growth at the end of the branch tips; thus, creating a distribution pattern similar to a lion’s tail. This type of pruning concentrates all of the tree’s weight at the ends of the branches, increasing the likelihood of branch breakage due to wind and/or storms.

Trees require interior foliage for proper photosynthesis and structural support. Removing interior branches takes away the tree’s ability to develop reaction wood, which is a type of wood that develops on branches under stress and provides additional structural support to the branches against wind loads and other stresses.

Proper Canopy Thinning Techniques

Proper canopy thinning involves removing select branches throughout the tree’s crown while maintaining the tree’s natural shape and balanced weight distribution. Professional arborists remove no more than 20% of the living canopy and remove dead, diseased, and structurally defective branches first.

Proper thinning improves air circulation and sunlight penetration while still providing adequate foliage for tree health. This balanced approach minimizes the risk of damage from storms while still allowing the tree to produce energy and maintain its structural integrity.

Ignoring Tree Species and Growth Patterns

Many homeowners unknowingly prune trees using generic pruning techniques that are not suitable for the tree species, or that do not consider the tree’s natural growth patterns, wood strength, and ability to heal from wounds. This lack of consideration can lead to poor pruning results and potentially cause damage to the tree.

For example, some species, such as oak and elm, can compartmentalize wounds well and can tolerate larger pruning cuts than species such as maple and birch, which seal poorly and require smaller cuts to minimize the risk of decay.

Understanding these differences is important for successful tree care.

Specific Considerations Based on Tree Species

Fruit trees typically require specialized pruning techniques that balance fruit production with the health of the tree. Fruit trees often require more aggressive pruning than most ornamental trees can tolerate.

On the other hand, many ornamental trees thrive with little to no pruning beyond routine maintenance pruning.

There are specific considerations for evergreen species versus deciduous species, with timing and technique varying greatly between the two types of trees and impacting their aesthetic appeal and health. Professional arborists recognize these differences and modify their pruning techniques accordingly.

Hazards Associated With DIY Tree Trimming

DIY tree trimming poses serious threats to the homeowner. Performing tasks such as working with chainsaws, climbing ladders while carrying pruning tools, and dealing with falling branches requires extensive training and specialized safety equipment that most homeowners lack.

The hazard associated with removing large branches is especially pronounced, as falling branches can inflict serious injury or cause property damage. Professional arborists use specialized rigging techniques and safety equipment to safely remove branches and protect people and property during the pruning operation.

Insurance and Liability Considerations

Homeowners who attempt to complete complex tree-trimming projects may find that their insurance policy does not cover any injuries or damage to property resulting from their own DIY tree-trimming activities. Lack of coverage can expose homeowners to significant financial liability in the event of accidents occurring during tree-trimming projects.

Professional tree-trimming companies carry specialized insurance and adhere to industry safety standards that protect both employees and property owners. Choosing a professional tree-trimming company that is properly insured and certified will provide homeowners with critical protection against liability risks.

Mistakes in Tools and Equipment

Using incorrect tools represents another common mistake in trimming that can damage both the tree and the equipment. Dull chainsaw blades create jagged cuts that are prone to infection and delay healing, while inadequate tools force homeowners to make multiple cuts, thereby increasing the size of the wound and the time required for healing.

Many homeowners mistakenly use hand pruners or small saws designed for small cuts to prune large branches. Using tools that are not capable of completing the task results in incomplete cuts, bark damage, and potential safety hazards related to equipment failure or binding.

Arborist Tool Choices

Arborists choose a variety of tools for various applications, including hand pruners for small branches, loppers for medium branches, and professional-grade saws for large cuts. Each tool has its own unique function and size range, and provides clean cuts that facilitate proper healing.

Regular sharpening and cleaning of tools is essential to prevent the spread of disease between trees and to assure optimal cutting performance. Arborist companies invest in quality tools and properly maintain those tools for consistency in results.

Treatment of Wounds and Post-Pruning Care

Many homeowners incorrectly assume that applying wound treatments, paints, or sealants to pruning cuts is beneficial. However, such treatments actually disrupt the natural processes involved in the healing of the tree. Trees have developed effective means of responding to wounds, and the most efficient healing occurs when these processes are allowed to operate naturally.

Research indicates that applying wound treatments can entrap moisture and create conditions favorable for decaying organisms. Properly made cuts in the correct location and at the correct time will heal most efficiently without artificial aid.

Promoting Natural Healing

The best way to promote the recovery of the tree is to promote the overall health of the tree through proper watering, fertilization, and monitoring for pest and disease issues. Healthy trees will rapidly and efficiently repair pruning wounds and require no additional treatment.

After pruning, the primary concern should be minimizing additional stressors that could impede the tree’s ability to heal and recover from pruning. Arborist services provide education on post-pruning care that promotes rapid healing and long-term health of the tree.