Mechanical Damage to Trees

Tree knocked down by vehicle

Trees in the city face a number of challenges. They have to deal with air pollution, compacted and poor quality soil, salt off city roads, limited root and/or canopy space to grow, insufficient and/or excess moisture and light, wind, snow, and ice damage, and of course mechanical damage.

Mechanical Damage to Trees

Mechanical damage to trees is potentially fatal

Mechanical Damage to trees occurs when a tree is hit by something. Whether the damage comes from a lawn mower, string trimmer, chainsaw, backhoe, or car, the results are the same; the tree sustains a wound of some sort. Sometimes fatally.

In the City of London, when a city tree is damaged (as in the case of a motor vehicle accident), a police report is filed. An inspector comes out to assess whether the tree will survive the damages or if it needs to be removed. Where necessary, a fine is levied for the cost of tree and stump removal, and new tree planting.

Young trees are often the most vulnerable to mechanical damage. Damage to the cambium layer of a tree affects sap flow, which may in turn weaken the tree. It also creates an entry point for insects and disease infestation, like oak wilt or emerald ash borer.

Equipment can easily damage trees during construction projects

Damage can also occur to a tree during construction projects. Whether a machine hits the trunk, branches, twigs, leaves, or damage occurs at the root zone during digging, health of a tree becomes compromised. Proper construction planning should be done beforehand to assess potential damage to surrounding trees.

Protection Against Mechanical Damage to Trees

How can you protect your trees against mechanical damage? A little forethought goes a long way.

Tree guards offer protection against mechanical damage by lawn mowers and string trimmers

• reduce your speed when roads become wet or slippery to ensure you maintain control of your vehicle and can steer clear of trees near roadways
• remove grass from the base of trees, to reduce risk of lawn mower or string trimmer damage
• apply a layer of mulch around a tree to reduce grass and weeds, and any disturbances caused by maintaining them
  • this also prevents soil compaction, due to machines or people treading close to the tree
• fence off trees before construction projects begin to reduce the risk of mechanical damage during the project
• be aware of a tree’s surroundings and vulnerabilities when in proximity to them
  • watch for twigs, branches, leaves, trunk and the root zone