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Tree Liability Risk:
The Duty of Care Owed to Persons Who May Be Harmed by Trees
Last Updated: August 22 2026
Question: When can I be liable in Ontario for injuries or property damage caused by a falling tree or limb?
Answer: In Ontario, a property owner or the person in control of trees may face liability if a court finds a duty of care to keep people and property reasonably safe, reasonable maintenance was not done, and the owner had actual or constructive knowledge of a dangerous condition before the incident, rather than the limb simply falling on its own; the occupier’s duty is set out in Occupier’s Liability Act, R.S.O. 1990, c. O.2, s. 3(1) and negligence analysis often traces to Donoghue v. Stevenson.
For tree maintenance cases, decisions like Hallok v. Toronto Hydro Electric System Ltd., 2003 CanLII 8519, highlight that liability typically requires evidence of knowledge (or what a reasonable person ought to have known), including situations after storms where broken branches should reasonably be investigated, and willful blindness may support constructive knowledge; to discuss your specific Ontario facts and next steps for a claim or defence, contact DK Legal Practice by phone at (416) 906-6663.
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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:
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).
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
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.
NOTE: A considerable amount of inquiries featuring “lawyers near me” or “best lawyer in” frequently indicate an urgency for competent legal assistance rather than merely seeking a specific title. In Ontario, “licensed paralegals” fall under the regulation of the same Law Society that governs lawyers, granting them the authority to represent clients in certain litigation matters. Core functions of this role include advocacy, legal analysis, and procedural expertise. DK Legal Practice provides legal representation within its licensed parameters, focusing on strategic positioning, evidentiary preparation, and effective advocacy to attain timely and beneficial outcomes for clients.