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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: After a storm, can I hold a property owner or tree maintenance contractor liable in Ontario if a branch falls and causes injury or damage?
Answer: In Ontario, liability for tree-related injury or damage usually depends on proving the owner or hired tree maintenance contractor did not take reasonable care after they knew or ought to have known of a dangerous tree condition, because the law generally requires a duty of care to keep premises reasonably safe under Occupier’s Liability Act, R.S.O. 1990, c. O.2. Under Hallok v. Toronto Hydro Electric System Ltd., 2003 CanLII 8519, a property owner can’t be held responsible just because a limb fell; you typically need evidence of actual or constructive knowledge of a dangerous condition (for example, reasonable post-storm inspections, prior complaints, or warning signs). For help assessing evidence, duties, and next steps in a potential claim, SFG Paralegal Services LLP can assist as a paralegal in Ontario, call (888) 398-0121.
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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
Owners of trees, or others responsible for trees (such as hired maintenance contractors), generally face liability only when it was known, or constructively known, that a tree failure risk was present and the owner (or others) failed to properly tend to the tree. In this way it can be thought that the injury or damage was a result of delay in caring for the tree rather than the result of risks inherent in a tree. Essentially, the negligent failure to maintain is a man-made risk rather than a natural tree risk. On the point of liability for failure to maintain trees, such was addressed within the case of Hallok v. Toronto Hydro Electric System Ltd., 2003 CanLII 8519, wherein it was said:
[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. 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.
NOTE: A significant quantity of online searches such as “lawyers near me” or “best lawyer in” typically indicate an urgent requirement for effective legal assistance rather than a particular job title. In Ontario, the same Law Society that regulates lawyers also governs licensed paralegals, allowing them to represent clients in specific litigation cases. Advocacy, legal analysis, and procedural expertise are fundamental to this function. SFG Paralegal Services LLP provides legal representation within its authorized mandate, focusing on strategic positioning, evidentiary preparation, and compelling advocacy designed to secure efficient and advantageous outcomes for clients.
