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Preventing Tree Damage during Construction or Landscape Renovation Projects

Maureen Sexsmith-West

ISA Certified Arborist, PR4600A

Many of you, me included, spend the cold days of winter snuggled in front of your favourite renovation shows on HGTV. By the onset of spring, you are dreaming of landscape or renovation projects. You are convinced you should take advantage of the shade from that mature tree by installing a new deck or patio. A well-landscaped yard can contribute significantly to your curb appeal, increase your living or use areas, and appreciate the value of your property. Working with established plants allows you to maintain the environmental benefits of shade, wind buffering, privacy and carbon capture that a mature landscape offers.

All too often, the most important aspect of the project is over looked – preservation of existing trees and shrubs BEFOREwork begins. Many property owners fail to consider the potential damage that can be done to trees during construction projects. Injuries such as broken branches and wounds to tree trunks are obvious. The damage to a tree’s root systems can result in tree failure or death.

Contractors may be well versed in construction building codes for driveway installations or building additions. Roofers need clear, safe access to install shingles. Even the best-intentioned DIY’er, who has read stacks of books from the library, lacks the professional training combined with years of experience that your local Certified Arborist can offer when it comes to tree health care.

Responsible planning, implementation, and aftercare will ensure that your trees can survive and thrive in harmony with the changes your urban lifestyles creates. Avoiding the expense of a tree preservation plan may save money up front but the potential for losses or future costs may quickly exceed the initial savings. A Tree Preservation Plan will ensure that the feature tree you planned your yard around is going to be providing benefits for years to come. Trees are sensitive to any changes to their growing environment; but they can be preserved if the appropriate measures are taken. More often than not, signs of decline start appearing a couple of years later. It is only then a tree care professional is contacted to address failing health issues.

Begin by asking these key questions. Will my project:

  1. require excavating the area between the trunk and drip line?

  2. result in interrupted irrigation?

  3. involve movement of vehicles over the roots?

  4. involve trenching for pipes or utilities?

  5. involve the installation of materials such as concrete, asphalt, gravel or brick?

  6. require pruning or removals to facilitate construction or equipment access?

  7. require stockpiling of construction materials on site?

If you can answer yes to even one, you should contact a Certified Arborist before any work begins.


Random pruning and leaving stubs creates an unsightly tree that is open the insect and disease problems. NEVER TOP YOUR TREE. Some trees have regulated pruning dates or ‘best’ seasons. In some cases, municipalities have tree protection by-laws. They can include restrictions when working around municipal trees, permits may be required when considering removal of certain species, set backs and so on. Your Certified Arborist should be knowledgeable on local laws and regulations.

Changes in grade can either expose the roots causing them to dry out or end up buried below the available oxygen. On an established tree – roots have developed at the optimum depth. Any changes of soil depth can have devastating consequences for your tree.

Removal or cutting of structural roots can make your tree unsafe. The closer the damage is to the trunk the greater the likelihood of tree failure. Excavation for foundations and driveways or trenching for irrigation systems and utilities are typical examples. In windy or stormy conditions, the tree may not be able to remain upright.

Injury or removal of roots can starve your tree. Since these are essential to the movement of water and nutrients throughout the tree, disruption to the flow is like having a leaky or burst water pipe. The pressure drops or flow stops altogether starving all or part of the tree.

Soil Compaction. Roots need oxygen to function and grow. The weight of excavators, haul trucks or repeat traffic, and stockpiled construction materials can force air pockets out of the soil. In extreme cases, soil can become as hard as concrete. Roots are likely to die – branches and leaves along with them.

Random disposal of construction products such as paint thinners or concrete overruns can negatively affect the growing environment by introducing toxins into the soil killing beneficial microorganisms.

Avoid creating planting sites that restrict health root growth: Cement borders and curbs can significantly restrict normal root development. As seen in this photo – the roots could not expand outside the framework. The roots became damaged by the rough surfaces, absorbed elements from the concrete, which resulted in significant pH variations, and an unstable anchoring system from encircling root growth.



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