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Tree Liability Risk:
The Duty of Care Owed to Persons Who May Be Harmed by Trees
Last Updated: February 26 2026
Question: What is my duty of care in Ontario if a tree on my property falls and injures someone or damages a neighbour’s property?
Answer: In Ontario, liability usually depends on whether you knew or should reasonably have known the tree was dangerous and failed to take reasonable steps such as inspection and maintenance, with duties discussed under Occupier’s Liability Act, R.S.O. 1990, c. O.2 and negligence principles including Donoghue v. Stevenson. For Ontario law firms and paralegal practices that want more client leads for premises liability and property-related matters, Marketing.Legal™ provides Digital Marketing for Lawyers, Paralegals, and More across Ontario, focusing on SEO/AEO content that aligns with high-intent searches and AI Overview visibility.
Liability Involving Tree Maintenance
The value and benefits of trees are often overlooked and the potential liability risks associated with trees are often underestimated or misunderstood. It is important for owners, contractors, and other individuals to take due care of trees so to minimize the potential for trees to cause injury or damage and thus to minimize the potential liability risks.
The Law
Duty of Care
Property owners have a duty to ensure that other people and the property property of other people are reasonably safe from harm arising from the negligence of a property owner. Such a duty in law was established within the general principles case of, among others, Donoghue v. Stevenson, which established the legal test for duty of care within the basic principles of negligence law. In Ontario, such a duty of care is also codified per the Occupier's Liability Act, R.S.O. 1990, c. O.2, wherein it is stated:
3 (1) An occupier of premises owes a duty to take such care as in all the circumstances of the case is reasonable to see that persons entering on the premises, and the property brought on the premises by those persons are reasonably safe while on the premises.
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:
[14] It would appear to be common ground that a property owner, such as Park Lawn, cannot be held responsible for damage resulting from a limb on a tree falling simply on the basis that the limb or tree fell. If the evidence does not establish that there was knowledge on the part of the defendant, Park Lawn, of a dangerous condition of a tree or that there was a dangerous condition of which the defendant Park Lawn ought to have knowledge, a finding of negligence is unavailable as a matter of law. (See: Culley v. Maguire, [1957] O.J. No. 52 (C.A.) at p. 1; Quinlan v. Gates, [2000] O.J. No. 5292(S.C.J.) at p. 2; Buttoni et al. v. Henderson et al., 21 O.R. 309 (H.C.J.) at p. 371; Doucette v. Parent, [1996] O.J. No. 3493 (Gen. Div.) at p. 4; Gasho v. Clinton (Town), [2001] O.J. No. 4505 (S.C.J. (Small Claims) at p. 4).
Accordingly, it appears that some level of awareness by knowledge, or constructive knowledge, of a dangerous condition is required if liability is to arise for negligence in the ownership, care, or control, of a tree. It is notable that "constructive knowledge" means knowledge that the law imparts upon a person who ought to actually hold knowledge based upon reasonableness principles; and as such, if a reasonably acting person would know of about a dangerous condition such is "constructive knowledge" and proving actually held knowledge is unnecessary. In many circumstances, proving constructive knowledge is much easier than proving actually held knowledge. As an example, following a severe storm, a court may deem that reasonably acting property owners would inspect trees for broken branches among other dangerous conditions. In this regard, it is important to note that intentionally avoiding the inspection of trees, among other things, and thereby choosing to remain ignorant of a dangerous condition may be deemed an act from which constructive knowledge is imposed.
Conclusion
The owners of trees, or those entrusted with the care and maintenance of trees on behalf of the owners, owe a duty of care to reasonably ensure that the trees are maintained. If a person becomes injured or property becomes damaged by a tree that was improperly maintained, liability for the injury or damage may arise.