If you’re getting an arborist report or a tree protection plan together for a Toronto project, don’t be surprised to see trees on it that aren’t yours. The city defines the area a report has to cover, and that area reaches onto the neighbour’s yard and the road allowance whether you like it or not.
The Six-Metre Rule Starts at the Disturbance, Not the Property Line
The area a report has to cover comes from the city’s Tree Protection Policy and Specifications for Construction Near Trees. Protection under Chapter 813 “extends 6m beyond the limit of site disturbance,” and the limit of site disturbance includes construction traffic and material storage, not just the footprint of the addition or the pool. On a ravine lot, that buffer doubles: the same policy extends the area “12m area beyond” the disturbance for ravine-protected trees.
Six metres from your excavation, not six metres from your fence. If equipment staging or material laydown pushes the disturbed area toward the property line, the 6-metre zone follows it and doesn’t stop at the line. The policy tells arborists to show every tree within that area on the tree protection plan, and says plainly that “depending on the extent of site disturbance, trees on neighbouring properties may need to be included.”
The same document puts the burden on you to talk to the neighbour before anything happens near a shared tree. It’s the applicant’s responsibility to discuss potential impacts to trees near or on adjacent properties directly with the neighbour, and if such a tree ends up injured to the point of instability or death, the applicant can face civil liability and be required to replace it to Urban Forestry’s satisfaction.
Street Trees Don’t Get a Size Exemption
Private trees need a permit once they hit 30 cm DBH (diameter at breast height, measured 1.4 metres above grade). Trees on the road allowance don’t get that exemption at any size. Chapter 813 defines a street tree as “any tree, all or part of which is located on, above or below a City street,” and injuring, destroying, or removing one without a permit is prohibited, full stop, regardless of trunk diameter.
That boulevard maple in front of your driveway, smaller than the 30 cm threshold that applies to your own trees, still needs a permit before anything touches it. A permit for injury to a city-owned tree runs $436.39 per tree, and the city can attach conditions to any root pruning of one, including payment of the tree’s value, replacement costs, and a letter of credit.
A Neighbour’s Tree Still Needs a City Permit
Toronto’s bylaw doesn’t ask who owns a tree before deciding whether you need a permit to affect it. Section 813-12’s permit requirement applies to any protected tree at 30 cm DBH or larger, and none of the listed exceptions depend on ownership. A tree whose trunk sits entirely on the neighbour’s property but whose roots or canopy reach onto yours still falls under Chapter 813 if your project will injure it.
The bylaw has a name for this: a “neighbour tree” is one whose trunk grows wholly on one property and that becomes the subject of an application to injure or destroy, filed by the adjacent owner. Once that application goes in, the city is required to notify the tree’s owner in writing and to tell the applicant that the arborist report, tree protection plan, survey, and any other supporting documents will be shared with that owner. There’s no quiet way to get a permit affecting a tree you don’t own. Applying for one costs $304.51 for a non-construction application and $913.58 where construction is involved.
Boundary Trees Belong to Both Owners
A different category applies when the trunk itself sits on the line. Under the Forestry Act, “every tree whose trunk is growing on the boundary between adjoining lands is the common property of the owners of the adjoining lands.” Injuring or destroying a boundary tree without both owners’ consent is a provincial offence.
Whether a tree counts as a boundary tree isn’t only about where it pokes out of the ground. In Hartley v Cunningham, the Ontario Court of Appeal read “trunk” as the whole trunk, from where it grows out of the roots up to where it branches into limbs and foliage, and held there’s nothing in the statute limiting that meaning to ground level. A tree can qualify as a boundary tree because of where the trunk crosses the line higher up, not just at grade.
Co-ownership can leave a hazardous boundary tree stuck if one owner won’t consent to its removal. That’s what happened in Freedman v Cooper: a boundary Norway maple was flagged as hazardous by an arborist, the city issued a removal permit, and one co-owner still refused to agree. The court didn’t reach for the Forestry Act’s offence provision. It held that provision doesn’t apply to the tree’s own owners, and ruled instead that the hazardous tree was a nuisance the objecting owner was obliged to let be abated. That owner was ordered not to interfere with the removal and to cover half the cost, $2,940.50.
Damage Runs Through Three Separate Tracks
Hurt a tree that isn’t only yours, and the exposure isn’t a single bill. It can run through three separate tracks, and they don’t overlap.
The Forestry Act covers boundary trees specifically. Injuring or destroying one without both owners’ consent carries a fine of up to $20,000, imprisonment for up to three months, or both, and that penalty applies regardless of any lower fine set by a municipal bylaw.
Chapter 813 runs its own prosecution track, sections 813-25 through 813-29, for any protected tree: neighbour, boundary, or city-owned. The city can inspect, order remedial work at your expense, and back it with fines from $500 to $100,000 per tree plus a special fine of up to $100,000. For a damaged city-owned tree specifically, the city also charges the tree’s appraised value on top of any fine, calculated under its own tree appraisal method. Ravine-protected trees carry the same $500 to $100,000 range under Chapter 658, plus a continuing fine of up to $10,000 per day if the situation isn’t fixed.
Then there’s civil liability, separate from either offence. In Murphy v Mullen, the Ontario Court of Appeal upheld $213,471.27 in trespass damages for cutting trees on someone else’s property, using the cost of restoring the site because there wasn’t enough evidence to support the alternatives the parties argued for (the value of the trees themselves, or the drop in the land’s value). The components the court pointed to included $73,902 to replace a third of the tree line, $20,000 for irrigation repairs, $13,000 for fencing, $75,000 tied to windbreak, screening, and privacy value (accounting for roughly a twenty-year wait for replacement trees to mature), and $24,968 under the Drainage Act, on top of survey costs.
The September 2026 Changes Don’t Touch Any of This
If you’ve read about the bylaw amendments taking effect September 1, 2026, none of them change what’s above. The street-tree permit requirement, the definition of a street tree, the notice requirement for boundary and neighbour tree applications, and the 6-metre and 12-metre areas of consideration all carry forward unchanged. What did shift with those amendments is a set of definitions elsewhere in the bylaw, a new large-tree category, and steeper contravention penalties, covered in our rundown of the September 2026 changes. None of that touches whose trees end up in your report.
Getting the Six-Metre Zone Right the First Time
If your project’s disturbance area reaches within 6 metres of a tree you don’t own, whether it’s on the road allowance, the neighbour’s lot, or straddling the line, that tree belongs in your documentation before you file anything. Missing it doesn’t make the exposure go away. It just means you find out about it after the work is done, when the permit you need is harder to get and the bill is bigger.
Our construction arborist reports map every tree in the area of consideration, including the ones outside your property line, and flag which ones will need a permit application, a neighbour notice, or both before your project starts. Contact us with your site address and we’ll confirm what falls inside your project’s 6-metre zone before you’re committed to a design.
This post covers Toronto’s Chapter 813 specifically. For the Forestry Act rules on boundary trees and common-law pruning rights that apply across Ontario, see our neighbour tree disputes guide.