Whose tree is it? Tree removal permit rules in Oakville, Mississauga and Toronto

Autumn is when a tree gets marked for removal — the one leaning over the driveway, the one shading half a back lawn, the one that has not leafed properly in two years. Before anyone is booked, two facts decide what is legal: where the trunk stands, and how thick it is. A tree removal permit is required across most of the GTA once the trunk passes a threshold, that threshold is a different number in every municipality, and the tree nearest the road is frequently not yours to cut at all. Both facts can be settled in an afternoon, at no cost, and settling them first is the difference between a scheduled job and a bylaw charge.

Who owns the tree in front of your house?

Location decides ownership, and nothing else does. Oakville states the test plainly: ownership of a tree is determined by its location on either private property or a municipal right of way such as a boulevard or road allowance, regardless of who planted the tree. A previous owner who paid for the tree, watered it and pruned it for fifteen years did not buy it if it stands on the road allowance.

Toronto describes the same geography for Etobicoke and the rest of the city: a street tree may sit in the boulevard between the sidewalk and the road, or in a portion of a front yard next to the road or sidewalk. Any activity that can harm or remove a street tree of any size is prohibited without a permit. Toronto's page points homeowners at two ways to settle it — a survey of the property, which shows the measurement from the house to the property line and street curb, or a call to 311 to confirm who owns the tree.

Mississauga will send someone to answer the question. A tree ownership inspection is a free service request; the city says it completes the inspection within 30 business days and leaves a notice at the door with the details. The same page draws the line on the other common dispute: if the disagreement is between neighbouring private properties, the city regards it as a civil matter to be resolved by the property owners.

Milton's own trees page opens its removal section with the same instruction — before removing a tree, make sure the tree is entirely on your property — and recommends consulting a certified arborist where removal is necessary. It also flags a second layer that catches larger rural and edge-of-town lots, covered further down.

How thick does a private tree have to be before you need a permit?

Each municipality sets its own size trigger, and the numbers are far enough apart that a threshold learned at a previous address does not carry over. Every figure below was read off the municipality's own page in September 2026; the sources are listed at the end of this post.

There is a regional layer on top of the local one. Halton Region's Tree By-law 121-05 applies to properties containing all or part of a woodland greater than 0.5 hectares (1.1 acres), and to properties partly or entirely inside the Regional Greenlands system — now called the Natural Heritage System. Under it you may harvest up to 24 cubic metres of wood a year for your own use, following Good Forestry Practices; beyond that a harvesting permit is needed. Oakville's by-law expressly steps aside for woodlands and greenlands governed by 121-05, so a large lot at the edge of town can sit under the regional rule rather than the town one.

Measuring diameter at breast height so the number is defensible

The threshold is a diameter, and a tape around a standing trunk gives a circumference. Burlington and Toronto publish the same arithmetic for converting one into the other, and it takes about two minutes per tree with a tape and a phone calculator.

1. 1Measure up from where the trunk leaves the groundBurlington specifies 1.37 m (4 ft 6 in); Toronto specifies 1.4 m (4.5 ft). Mark that height on the trunk with a finger or a piece of tape.
2. 2Wrap the tape around the trunk at that markHold it at a 90-degree angle to the trunk, not to the ground — on a leaning tree those are different, and squaring to the ground inflates the reading.
3. 3Divide the circumference by 3.14That result is the diameter at breast height, or DBH. A trunk measuring 50 cm around is roughly 16 cm across, which already clears the Oakville and Mississauga thresholds.
4. 4Handle multiple stems the way your municipality doesToronto uses the largest stem: where at least one stem is 30 cm or more, the whole tree including every stem is protected. Burlington combines them — square each stem's diameter, add the squares, take the square root of the total.
5. 5Write the number down with the date and a photoA measurement you can show, taken before any work, is what an inspector or a permit reviewer asks for. It also stops a second opinion from starting the whole discussion again.

Pruning counts as injuring a tree, up to a point

These by-laws regulate injury as well as destruction, so the question is not only whether a tree comes down. Where the line falls is written differently in each place:

• Burlington exempts private tree maintenance defined as pruning no more than a third of the live crown of a tree within good arboricultural practice. Past that third, the exemption stops applying.
• Mississauga requires a permit to injure, remove or prune a public tree, and to injure or remove a private tree at or above 15 cm.
• Toronto phrases it as any activity that can cause a protected tree to be injured or removed — which covers root-zone excavation and grade changes, not only cuts.
• A dead tree is still a permit in two of these municipalities. Mississauga requires the permit for dead or dying trees but charges no base fee for them; Burlington requires a permit for a tree that is 100% dead, has a terminal condition or is high-risk, and waives the fees and compensation.
• Emergency work is treated separately. Oakville does not require a permit where a tree presents an immediate risk of serious injury or damage; Burlington accepts emergency removals provided supporting documents are supplied to the City afterwards.

None of this is aimed at shrub and perennial work. A cedar hedge, a spirea, a bed of coneflowers — those sit outside the tree by-laws entirely, and the timing questions there are horticultural rather than legal. Our notes on the last safe hedge and shrub cut of the year and what to cut and what to leave standing in the beds cover that side of the property.

The boundary tree rule, in the words of the statute

A tree growing on the fence line sits under provincial law as well as the municipal by-law. Ontario's Forestry Act settles who owns it and then makes cutting it an offence:

Every tree whose trunk is growing on the boundary between adjoining lands is the common property of the owners of the adjoining lands. … Every person who injures or destroys a tree growing on the boundary between adjoining lands without the consent of the land owners is guilty of an offence under this Act.

Two things follow. First, the test is where the trunk grows, not where the branches reach or where the roots run. Second, consent has to come from the owners — plural — so a written note from the neighbour, dated, naming the tree and the work, is the document to have before a saw arrives. If the neighbour disagrees, that is the civil matter Mississauga describes, and it is settled between owners rather than by the city.

The related autumn question — branches from next door overhanging your roof and filling your eaves — is a property question rather than a tree-removal question, and worth separating from the trunk. What the gutters do under a mature canopy is covered in how often eavestroughs actually need clearing here, and clearing them is gutter work rather than tree work.

What changed in Toronto on 1 September 2026

Toronto amended Chapter 813 (Trees) and Chapter 658 (Ravine and Natural Feature Protection) with several changes that took effect on 1 September 2026. Anyone who checked the rules earlier in the year is working from a stale answer:

• A new Distinctive Tree category covers large healthy trees on private property and in ravines more than 61 cm in diameter. Distinctive Trees are identified by City staff and must be considered when a permit application is made to injure or remove them.
• Stump diameter of 40 cm or greater can now be used as a secondary measurement when a removed tree's trunk can no longer be measured — cutting first does not erase the evidence.
• Trees planted through enforcement actions or development approvals now require a permit for injury or destruction regardless of size.
• Replacement ratios for contraventions shift to a diameter-based system starting at 5:1 and increasing for larger trees.
• Separately, City Council has endorsed lowering the private threshold from 30 cm to 20 cm, pending an analysis and implementation strategy going to the Infrastructure and Environment Committee in 2027. It is not in force today; a Toronto homeowner planning work for next year should watch for it.

The order to work in before you book anyone

1. Walk the front and back with a tape. Measure the DBH of every tree you are thinking about and write the numbers on your phone with the date.
2. Settle ownership for anything near the curb — a survey, a call to 311 in Toronto, or a tree ownership inspection request in Mississauga. Do this first, because it can take up to 30 business days there and the answer changes who you are even allowed to call.
3. Check whether the property sits inside a ravine or natural feature area (Toronto), the Urban Planning Area Boundary (Burlington), or a woodland or the Halton Natural Heritage System (Halton Region). Each of those replaces the ordinary threshold.
4. If a tree is on the boundary, get the neighbour's written consent before anything else. Nothing downstream is worth arranging without it.
5. Apply for the permit if one is needed, and read the replacement condition in the same sitting — Mississauga requires one replacement tree for every 15 cm of diameter removed, and its replacements must be native shade-bearing species at least 1.8 m tall if coniferous or 6 cm in diameter if deciduous, with Japanese maples, cedars and junipers excluded.
6. Only then book the work, and hand the crew the permit number along with the address.

There is a point in this where the honest answer is to hire nobody. A small ornamental well under the threshold, a bit of deadwood you can reach from the ground, a light shape-up inside a third of the live crown on your own tree — that is a Saturday, not a contract. A protected tree, anything over a roof or near a service line, and anything you would need a ladder and a running saw to reach at the same time belongs to a certified arborist, which is exactly what Milton and Mississauga both recommend on their own pages. What sits comfortably between the two is the rest of the autumn work — cleanups, bed and shrub cutback, and replacement planting once a permit sets the number of trees that have to go back in — which is ordinary landscaping and seasonal cleanup work.