Treatment of Trees Damaged by Construction
Tree damage assessment and remedial treatments that may preserve trees damaged during construction.
By TreesAreGood®
International Society of Arboriculture
Construction and Trees
Construction can be devastating to surrounding trees if measures are not taken. Remedial treatments may save some trees, but immediate implementation is critical. A professional arborist can assess tree viability and risk potential to recommend treatment options for construction-damaged trees.
Damage Caused by Construction
• Physical injury to the trunk and crown.
• Soil compaction in the root zone.
• Severed roots.
• Smothered roots from added fill soil.
• Increased wind and sunlight exposure.
• Stress due to grade and drainage changes.
Inspection and Assessment
A certified arborist should check for potential risk to the structure and stability of a tree. A risk assessment may involve visual inspection, or instruments may be used to check for decay.
Risks That Can Be Addressed
They can identify risks that can be reduced or eliminated by:
- removing an unsafe limb
- pruning to reduce weight
- installing cables or braces for structural support
Branch Damage
• Remove split, torn, or broken branches. Remove dead or diseased limbs from the crown.
• Generally do not reduce tree canopies to compensate for root loss; however, there are some cases where this is the best option.
• There is no conclusive research to support the practice of routine thinning for reducing water stress.
Treating Damaged Bark and Trunk Wounds
Often the bark may be damaged on the trunk or lower branches. Remove the loose bark. Jagged edges can be cut away with a sharp knife. Be sure not to cut 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.
Proper Watering
A long, slow soak over the entire root zone is the preferred method of watering. Avoid frequent, shallow watering or overwatering. If the soil is poorly drained, the irrigation level should be reduced to avoid saturating the soil, or drainage should be improved.
Wound Dressings
Wound dressings were once thought to be beneficial. However, research has shown that dressings generally do not reduce decay or speed closure and rarely prevent insect or disease infestations. If a dressing must be used for cosmetic purposes, use only a thin coating of a nontoxic material.
Mulching
Apply a 2-4 inch (5-10 cm) layer of organic mulch over a tree’s root system to enhance root growth. The mulch should extend until the dripline or as far out from the tree as practical for the landscape site. Mulch helps condition the soil, moderate soil temperatures, maintain moisture, and reduce competition from weeds and grass.
Cabling and Bracing
If branches or tree trunks are likely to fail, an arborist may be able to install cables or bracing rods. If installed, they must be inspected regularly. The added security offered by the installation of support hardware is limited. Not all weak limbs require these measures.
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