GTA municipal tree preservation requirements
Tree bylaws in the Greater Toronto Area are not standardized. Every municipality has its own bylaw, its own size thresholds, its own application process, and its own urban forestry staff with their own submission expectations. What clears review in Hamilton may generate comments in Oakville. What works in Toronto may not be the right format for Burlington.
This page provides a practical overview of tree preservation requirements across the GTA municipalities I work in most frequently. It is intended to help developers, builders, landscape architects, and property owners understand what they're likely to encounter before they engage an arborist, not as a substitute for site-specific advice.
Bylaws change. This page reflects requirements current as of early 2026, but municipal bylaws are amended regularly. Verify current requirements directly with urban forestry staff at the relevant municipality before proceeding.
Why requirements vary across the GTA
When Toronto amalgamated and as municipalities across the region developed their own urban forest strategies over the past two decades, each one built its own regulatory framework. The result is a patchwork of bylaws with different thresholds, different fee structures, different submission requirements, and different enforcement priorities.
The variation matters practically for a few reasons. The size threshold that triggers permit requirements ranges from 15 cm diameter in Oakville and Mississauga to 20 cm in Burlington and 30 cm in Toronto. A tree that requires a permit in Oakville may not require one in Toronto. Replacement ratios differ. Review timelines differ. The format and content of arborist reports that satisfy municipal staff differ.
Working across multiple municipalities is one of the things an experienced consulting arborist brings to development projects. Understanding what each urban forestry department expects, how staff approach applications, and where the friction points tend to be, is practical knowledge that saves time.
Toronto
Toronto's tree protection framework is among the most complex in Ontario because it operates through multiple overlapping bylaws.
Private Tree By-law (Chapter 813, Article III) protects trees on private property with a diameter of 30 cm or greater at 1.4 metres above ground. No person may injure, destroy, or remove a protected private tree without a permit. The application must be accompanied by an arborist report. For development and construction applications, a tree protection plan is also required. Public notice may be required for removal of healthy trees, giving neighbours 14 days to comment.
Street Tree By-law (Chapter 813, Article II) protects all trees on City streets, including those on City-owned portions of what appear to be front yards, regardless of size. In older Toronto neighbourhoods, the City often owns the first 4.5 metres or more of what looks like private property. Any construction that could affect a street tree requires a permit and arborist report. Permits for street trees are notably more difficult to obtain than for private trees.
Ravine and Natural Feature Protection By-law (Chapter 658) protects trees of any size within designated ravine areas. Ravine permits involve a separate review process and typically require an environmental assessment component in addition to arborist documentation.
In practice, most urban infill development sites in Toronto encounter at least two of these bylaws. A laneway suite on a typical Toronto lot may involve the private tree bylaw for trees on the subject property, the street tree bylaw for boulevard trees near the construction access, and ravine protection if the lot is adjacent to a designated ravine.
Toronto Urban Forestry has a formal site plan review role. Arborist reports and tree protection plans submitted as part of development applications are reviewed by urban forestry staff, who issue comments as part of the site plan approval process. Those comments must be resolved before site plan approval is granted.
Fines for unlawful injury or removal of protected trees in Toronto range from $500 to $100,000 per tree. The City actively enforces the bylaw and issues stop-work orders for construction violations.
Key contacts: Toronto Urban Forestry, 311 or urbanforestry@toronto.ca
Mississauga
Mississauga's tree protection is governed by the Tree Permit By-law (Number 474-05). Permits are required to remove or injure trees on private property that are 15 cm or greater in diameter, including dead and dying trees. Notably, Mississauga requires arborist reports for all development and construction projects involving permit applications, regardless of the tree's condition. Dead and dying trees are an exception for arborist report requirements but permits are still required.
Permit fees are set by the City's User Fees and Charges By-law, which is updated periodically. Current fee schedules are available at mississauga.ca or by calling 311. Replacement planting is required at a ratio of one replacement tree for every 15 cm of diameter of the removed tree — so a tree with a 45 cm diameter requires three replacement trees. A security deposit is held for one year after replanting.
Mississauga has 30 business days to review a complete application from the date it's received. Submitting an incomplete application resets that clock.
For development applications, Mississauga Development and Design reviews arborist reports as part of the site plan and planning act approval process. Urban forestry staff are consulted and issue conditions that must be satisfied before approvals are granted or building permits are issued.
Key contacts: Mississauga Urban Forestry, 905-615-4100
Oakville
Oakville has one of the more protective private tree bylaws in the GTA, with a size threshold of 15 cm diameter at breast height (1.37 metres above ground). Any tree meeting that threshold requires a permit before removal, and any removal resulting from a development application requires a full arborist report endorsed by a certified and licensed arborist.
The bylaw was strengthened significantly in 2017 and updated further at a March 2024 Council meeting in response to concerns about canopy loss from intensification. Oakville is actively working toward a 40 per cent canopy cover target by 2057, and staff apply that goal with some discretion in permit reviews.
For construction projects, applicants go through a consultation process before removal permits are issued. Oakville forestry staff conduct a site visit, review the arborist report, and issue a decision letter specifying which trees can be removed, which must be protected, and the specifications for tree protection measures. The removal permit and any required tree protection agreements are issued after protection hoarding is inspected and fees and securities are paid.
Arborist reports for development projects in Oakville are expected to include tree amenity values calculated using the ISA Guide for Plant Appraisal (9th or 10th Edition), risk assessments where required (ISA Level 2 methodology for development applications), and TPZ encroachment applications where protection zone conflicts are unavoidable.
The Town also has a separate process for Town Tree Protection Zone Encroachment if construction must occur within the protection zone of a municipal tree.
Key contacts: Oakville Parks and Open Space, 905-845-6601
Burlington
Burlington's tree protection operates under two bylaws: the Private Tree By-law (040-2022) and the Public Tree By-law (098-2025), which was amended in December 2025 to align with and strengthen the private tree framework.
The private tree threshold in Burlington is 20 cm diameter at 1.4 metres above ground within the urban boundary zone. Permit fees follow a tiered structure: $50 application processing fee plus $325 for one to three removals, $225 per tree for the fourth removal, and $125 per tree for the fifth or more. Cash-in-lieu replacement is $250 per replacement tree. Dead, dying, and hazardous trees still require permits, though fees are waived.
Burlington Urban Forestry is involved in development application review as a commenting body. For construction projects, arborist reports must identify all trees within the zone of influence, specify protection measures, and address any required root pruning or grade change mitigation.
One practical note about Burlington: I worked the Burlington municipal street tree pruning contract during my final period with Davey Resource Group, and developed working relationships with Burlington urban forestry inspectors during that time. That direct familiarity with how Burlington staff approach tree protection review is useful context for projects in Burlington.
Key contacts: Burlington Urban Forestry, 905-335-7600
Hamilton
Hamilton's tree protection situation is currently in transition. The City has existing private tree bylaws inherited from the pre-amalgamation municipalities, including bylaws for the former City of Hamilton, Ancaster, Dundas, and Stoney Creek, which have different thresholds and provisions.
As of early 2026, Hamilton is working toward a unified private tree bylaw. Staff have recommended a 45 cm diameter threshold based on the former Ancaster bylaw, which would require permits for private tree removal above that size. A public consultation process has been underway, and the bylaw has not yet passed.
For development applications, Hamilton's Tree Protection Guidelines govern how trees must be assessed and protected on development sites. These guidelines require that all trees within the proposed development area, extending 6 metres beyond the proposed work area, be surveyed, identified, and accurately plotted on the plan. The tree survey must be prepared by an ISA Certified Arborist, Registered Professional Forester, or Landscape Architect.
Hamilton requires a Verification of Tree Protection Letter before rough grading can begin, before servicing commences, or before a building permit is issued. The grading consultant must confirm that the tree protection plan conforms to the Lot Grading Control Plan before those plans are approved.
Loss of canopy fees apply to public trees approved for removal, calculated using the Trunk Formula Method.
I am based in Hamilton and work regularly with Hamilton Planning and Hamilton Urban Forestry on development applications. Familiarity with local staff expectations and the current transition in Hamilton's private tree bylaw framework is directly useful for projects in the city.
Key contacts: Hamilton Urban Forestry, urbanforest@hamilton.ca | Hamilton Planning, 905-546-2424
Other GTA Municipalities
Vaughan
Vaughan requires permits to injure or remove any tree over 20 cm in diameter at the base, or any multi-stem tree with a combined diameter over 20 cm. The permit application requires an arborist report, colour photographs of the tree, digitally produced plans showing all trees on the property, and a $70 fee. Replacement planting of one to four trees is required depending on the size of the removed tree, or a cash payment in lieu.
For development applications in Vaughan, urban forestry is a commenting body in the site plan and development application process. Vaughan is a high-growth municipality with substantial infill and intensification activity, particularly in the Vaughan Metropolitan Centre and along major corridors.
Markham
Markham protects trees on private property under its Private Tree By-law. Development applications involving trees are reviewed with arborist report requirements consistent with GTA municipal standards. Markham is actively densifying along Yonge Street and in its major transit station areas, generating significant infill arboricultural work.
Richmond Hill
Richmond Hill has a private tree protection bylaw that regulates tree removal on private property. Development applications involving trees require arborist reports and tree protection plans as part of the site plan and planning act approval process.
Brampton
Brampton's Urban Forestry division is involved in development application review. Arborist reports and tree protection plans are required for development projects affecting trees. Brampton's rapid residential growth means urban forestry conditions on development applications are common and actively enforced.
Halton Hills and surrounding Halton Region
Within Halton Region, individual municipalities have their own private tree bylaws (Oakville and Burlington, covered above). Halton Region itself administers the Halton Region Tree By-law, which governs woodlot harvesting on private and rural lands within the region. Harvesting more than 24 cubic metres of wood per year, or harvesting that doesn't follow good forestry practices, requires a permit under the regional bylaw.
For rural and agricultural lands within Halton, the regional bylaw is the relevant instrument, not municipal private tree bylaws.
How I help navigate these requirements
Working across multiple GTA municipalities means understanding each urban forestry department's expectations, submission formats, and review priorities. The bylaw thresholds above tell you what triggers a permit requirement. What they don't tell you is how staff interpret ambiguous situations, what level of report detail satisfies review without generating comment letters, or where the discretion lies in the system.
That practical knowledge comes from direct experience working in these jurisdictions. I've worked under the Burlington municipal street tree contract, completed projects cleared by Toronto Urban Forestry, and work regularly with Hamilton's planning and forestry teams. That experience informs how I prepare reports, what I address proactively, and how I engage with staff when questions come up mid-review.
If you have a project in one of these municipalities and you're trying to understand what tree-related requirements you're facing, a short conversation can usually get you oriented quickly.