Ontario Tree By-laws: Why Cutting Down a Tree on Your Own Property Can Require a Permit

The tree in your own yard isn’t entirely yours to remove. Here’s when a city makes you get a permit, how the size rule is measured, what it costs to ignore, and why buyers should check before they offer.

I’m Arthur Zhao, a Toronto real estate broker. Here’s a scene I’ve watched play out more than once: a homeowner calls an arborist for a quote to take down the big silver maple crowding the backyard, expecting a weekend job and a cheque — then learns the tree can’t legally be touched without a City permit, and that removing it anyway could cost more than a used car. The instinct is understandable: it’s your land, your tree, your call. On paper, it isn’t entirely. Tree protection is one of the few areas where a municipality reaches past your property line and onto the plant in your own yard. Below is how the rules actually work in Toronto — the numbers, the exemptions, the fines — and, just as important, why anyone buying a house should size up the trees on a lot before writing an offer.

It’s your tree — but not entirely your call to cut it down

Start with the counter-intuitive core: owning the land the tree stands on does not automatically give you the right to remove it. Many Ontario municipalities run a private-tree protection by-law that regulates trees on private property once they reach a certain size. Toronto is the clearest worked example, so I’ll use it throughout — but the key word is municipal. These rules are made city by city, not by the province, which means the specifics change with the address. Treat what follows as how the mechanism works, then confirm the exact numbers with the by-law of the city the property actually sits in.

How a tree becomes “protected” in Toronto: the 30 cm rule

So what makes a tree protected? In Toronto it comes down to size. According to Toronto Municipal Code Chapter 813, the trigger is a trunk 30 cm or more in diameter, measured at 1.4 metres above the ground — the standard forestry measure often written as DBH (diameter at breast height). Two details trip people up. First, it’s diameter, not circumference — a 30 cm-wide trunk is a substantial tree, but smaller than many people picture. Second, the rule catches multi-stem trees: a clump-form tree is protected if even one of its stems hits 30 cm at that height. So the ornamental birch or serviceberry with several trunks isn’t automatically in the clear.

What’s exempt — and the trap hidden in one word

Chapter 813 does carve out exemptions, but they’re narrower than people hope, and one word does most of the work: certified. A permit is not required to remove a tree that is terminally diseased, dead or imminently hazardous — but only once it has been certified as such by the City’s General Manager, not when you or your arborist decide it looks dead. Routine pruning that follows good arboricultural practice is exempt, as is genuine emergency work and pruning around utility lines (again, as certified by the City). The practical takeaway: “the tree is basically dead, so I can just take it down” is exactly the assumption that leads to a fine. Get the certification first.

The fines are not symbolic

According to Toronto Municipal Code Chapter 813, the penalties have real teeth. A person convicted of an offence is liable to a minimum fine of $500 and a maximum of $100,000 per tree — and the by-law says per tree in plain language, so clearing several protected trees multiplies the exposure. On top of that, the City can add a special fine of $100,000 (§ 813-29B, under the City of Toronto Act, aimed at stripping out any economic gain from the violation), and where the offender is a corporation, directors and officers who knowingly go along with it can be charged personally. The City can also stop the work the moment it finds unpermitted cutting of a 30 cm-or-larger tree.

For buyers: a single protected tree can quietly cap a lot’s potential

Here’s the part most buyers never think about at a showing: a mature, protected tree can quietly limit what you’re allowed to build. Planning a backyard addition, an inground pool, or a widened driveway? Each of those can put a construction footprint straight into the root zone of a protected tree. The City can issue a permit to injure or destroy a healthy tree only on limited grounds — for example, where it’s causing structural damage or genuinely can’t be maintained given the site — and even then it can attach conditions such as replacement planting or a cash-in-lieu payment (set at 120% of the cost to plant and maintain a replacement tree for two years). So a lot that looks like it has obvious room to expand may, in practice, be far more constrained than the survey suggests. If your reason for buying a particular house is what you plan to build on it, walk the lot with the trees in mind before you’re bound by an accepted offer.

Toronto is not “Ontario”: the threshold changes at the city line

Ravines and conservation land: a second, stricter layer

One more layer to know about: the 30 cm rule is the general private-tree standard, but it isn’t the only regime. Trees in designated ravine and natural-feature areas fall under a separate chapter of Toronto’s code (Chapter 658), and land inside a Conservation Authority’s regulated area carries its own permit requirements. In those zones a tree can be protected even if it’s well under 30 cm — so the reassuring “it’s only a small tree” logic doesn’t hold. If a property backs onto a ravine, a valley, a creek or protected green space, assume there’s an extra approval layer and confirm it specifically rather than applying the 30 cm number by default.

Arthur Zhao

Real Estate Broker · FRI · ABR · SRS · PSA · MCNE · E-PRO · CLHMS & GUILD Elite · REAIS

VP & Branch Manager, Bay Street Group Inc.

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