Homes are often constructed near existing trees to take advantage of their aesthetic and environmental value. Unfortunately, the processes involved with construction can be deadly to nearby trees. Proper planning and care are needed to preserve trees on building sites. An arborist can help you decide which trees can be saved. The arborist can also work with the builder to protect the trees throughout each phase of construction.

Planning

Your arborist and builder should work together early in the planning phase of construction. Sometimes small changes in the placement or design of your house or driveway can make a great difference in whether a critical tree will survive. If utilities cannot be re-routed away from trees, less damaging tunneling and trenching installation techniques exist.

Erect Barriers to Limit Access

The most effective way to prevent damage to trees during construction is erecting barriers to prevent physical damage to the tree and its roots. Set up sturdy fencing around each tree that is to be retained as far out from the trunk as possible, or approximately 1-foot (0.3 m) for each inch (2.5 cm) of trunk diameter.

If possible, limit access to the construction site to only one entrance/exit. Additionally, instruct all contractors where they are permitted to drive and park their vehicles, to help limit soil compaction and root damage. Limit areas permitted for cement wash-out pits, burning of construction materials, and/or equipment storage.

Maintain Good Communication

Communicate your objectives clearly to your arborist, builder, and all subcontractors. Visit the site at least once a day, if possible. Your vigilance will pay off as workers learn to take your wishes seriously. Take photos at every stage of construction.

Treatment of Trees Damaged by Construction

The processes involved in construction can be devastating to the surrounding trees if no measures have been taken to protect them. Remedial treatments may save some construction-damaged trees, but immediate implementation is critical. If you have trees that have been affected by recent construction, a professional arborist can assess tree viability and risk potential and recommend treatment options.

Learn more about the treatment of trees damaged during construction

Inspection and Assessment

Because construction damage can affect the structure and stability of a tree, your arborist should check for potential risks. A risk inspection may involve a simple visual inspection, or instruments may be used to check for the presence of decay. Identified risks can sometimes be reduced or eliminated by removing an unsafe limb, pruning to reduce weight, or installing cables or braces to provide structural support.

Common damage caused during construction includes:
  • physical injury to the trunk and crown
  • soil compaction in the root zone
  • severed roots
  • smothered roots from addition of fill soil
  • increased wind and sunlight exposure
  • stress due to grade and drainage changes

Treating Trunk and Crown Injuries

  • Pruning. Split, torn, or broken branches should be removed. Also, remove any dead or diseased limbs from the crown of the tree. It is best to postpone other maintenance pruning, such as crown raising, for a few years. Do not thin or reduce tree canopies to compensate for root loss.
  • Cabling and Bracing. If branches or tree trunks need additional support, a professional arborist may be able to install cables or bracing rods. If cables or braces are installed, they must be inspected regularly. The amount of added security offered by the installation of support hardware is limited. Not all weak limbs are candidates for these measures.
  • Treating Damaged Bark and Trunk Wounds. Bark may be damaged along the trunk or on major limbs. If this happens, remove the loose bark. Jagged edges can be cut away with a sharp knife. Take care not to cut into living tissues.
  • Irrigation and Drainage. One of the most important tree maintenance procedures following construction damage is to maintain an adequate, but not excessive, supply of water to the root zone. Water trees as needed, especially during the dry summer months. A long, slow soak over the entire root zone is the preferred method of watering. Avoid frequent, shallow watering or overwatering. Poor drainage must be corrected or trees will decline rapidly.
  • Mulching. Apply a 2- to 4-inch layer of organic mulch such as wood chips, shredded bark, or pine needles over a tree’s root system for a simple and effective means of enhancing root growth. The mulch helps condition the soil, moderates soil temperatures, maintains moisture, and reduces competition from weeds and grass. The mulch should extend as far out from the tree as practical for the landscape site.

Monitoring for Decline and Risk

Despite your best efforts, you may lose some trees from construction damage. Symptoms of decline include smaller and fewer leaves, dieback in the crown of the tree, and premature fall color. Stressed trees are more prone to attack by certain diseases and pests, which further a tree’s downward spiral. Severe damage and decline may also lead to defects and decay. Consult with an arborist for a professional assessment if you are concerned with your tree’s health or structural integrity.

Learn more about the treatment of trees damaged during construction