Tree Liability Risk:

Question: When can a property owner in Ontario be liable for injuries or damage caused by a falling tree or branch?

Answer: In Ontario, liability for a falling tree or limb usually depends on whether the owner (or a hired contractor) knew or should have known about a dangerous condition and failed to take reasonable care, consistent with duties under Occupier’s Liability Act, R.S.O. 1990, c. O.2 and negligence principles from Donoghue v. Stevenson.  Access Ontario Legal Services provides paralegal services for Milton, Ontario to help assess constructive knowledge, maintenance records, inspection expectations after storms, and next steps for a claim or defence.

Liability Involving Tree Maintenance

Although trees are extensively found throughout our urban and rural landscape, the value and benefits of trees are often taken for granted. Additionally, the potential liability risks are often unappreciated or misperceived. Owners and contractors, among others, should carefully heed the potential liability risks arising from the ownership, care, or control, of trees.

The Law

Duty of Care

The basic principles of common law, particularly negligence and the legal test regarding duty of care as founded within the Donoghue v. Stevenson case (a general principles case rather than tree specific case), prescribe that property owners owe a duty to ensure that other persons and the property of others persons is reasonably safe. In Ontario, these duties are also codified the Occupier's Liability Act, R.S.O. 1990, c. O.2, whereas it is said:

Negligently Performed Maintenance

Generally, the owner of a tree, or other persons responsible for the care of a tree such as hired maintenance contractors, will be held liable for injury or damage caused by the tree only when it was known, or constructively known, that a tree failure risk was present and the owner, or other person, failed to take proper care of the tree. Accordingly, it should be viewed that the injury or damage resulted due to neglect in the care of the tree rather than as a result of inherent risks. Essentially, it is the man-made risk of negligent failure to maintain a tree rather than an inherently natural tree risk that is said to give rise to liability for injury or damage. On the point that liability arises for the negligent failure to maintain trees rather than being absolute so to include inherent risks, such concerns were addressed within the case of Hallok v. Toronto Hydro Electric System Ltd., 2003 CanLII 8519, wherein it was stated:

As such, it seems that knowledge, or constructive knowledge, of a dangerous condition is a requirement of liability for negligent maintenance of trees.  Note that "constructive knowledge" is knowledge which the law deems a person ought to have based on reasonableness.  If a reasonably diligent person would know of a dangerous condition this is "constructive knowledge" and proving actual knowledge becomes unnecessary.  Constructive knowledge is often much easier to prove than actual knowledge.  For example, following severe storms, property owners should reasonably be on alert for broken branches as well as other dangerous conditions.  Additionally, it is important to recognize that intentionally avoiding investigation and thereby choosing to remain unaware of a dangerous condition may be deemed an act of willful blindness from which constructive knowledge may also be imposed.

Conclusion

Tree owners, or other persons who are hired to provide the care and maintenance of trees on behalf of the owners, are prescribed by law with a duty of care to reasonably ensure that the trees are maintained in a safe condition.  If a person becomes injured or if property becomes damaged by a unreasonably maintained tree, liability may arise.