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Tree Liability Risk:
The Duty of Care Owed to Persons Who May Be Harmed by Trees
Last Updated: July 02 2026
Question: When can I hold a property owner or tree maintenance contractor liable in Ontario if a tree limb or tree falls and causes damage or injury?
Answer: In Ontario, liability for tree-related injuries or property damage usually depends on negligence principles: the occupier or party responsible for the trees must take reasonable care to keep people and property reasonably safe, and in practice a claimant often needs to show the owner or contractor knew or should have known about a dangerous tree condition and failed to maintain it properly rather than the harm occurring simply because a limb fell. Under the Occupier’s Liability Act, R.S.O. 1990, c. O.2, s. 3(1), an occupier owes a duty to take reasonable care to ensure visitors and the property they bring are reasonably safe while on the premises, and courts have recognized that without evidence of actual or constructive knowledge of a dangerous condition, negligence is not established, including in Hallok v. Toronto Hydro Electric System Ltd., 2003 CanLII 8519. A Family Law Services Provider Paralegal at Denali Paralegal can help you understand how to frame your facts, gather key evidence like inspection history after storms, photos, witness statements, and maintenance records, and discuss next steps in Ontario, including options for limited-scope assistance, by phone at (877) 414-4377 across Toronto and surrounding communities.
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
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
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. 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 substantial amount of inquiries featuring “lawyers near me” or “best lawyer in” often indicate a demand for prompt and effective legal assistance rather than a particular job title. In Ontario, licensed paralegals operate under the same Law Society that governs lawyers and have the authority to represent clients in specific litigation issues. Skills in advocacy, legal analysis, and understanding of procedures are fundamental to this profession. Denali Paralegal provides legal representation within its licensed framework, focusing on strategic formulation, evidentiary readiness, and compelling advocacy aimed at securing efficient and advantageous outcomes for clients.