Some of the most common questions we receive from inquiring homeowners are related to existing trees in their backyard and how these will affect the viability (and process) to realizing their laneway or garden suite. In recent months, trees have become a prevalent topic in Toronto’s accessory dwelling unit community as the new garden suite by-law was subject to lengthy debate over its impact on our urban forest. This post will clear the air on the subject (pun intended).

Toronto’s low-rise neighbourhoods are the lungs of our city. They represent nearly 75% of our land area. The goal is to preserve our urban forest and ensure these secondary dwellings, while important to provide new housing, do not result in significant removals and a depleted canopy.


The Private Tree By-Law
The city of Toronto has a Private Tree By-law in place to ensure that mature healthy trees are not carelessly removed or negatively impacted by private development. Any tree with a trunk that measures over 30cm in diameter, at 1.4m above grade is subject to protection in the by-law. The by-law designates three types of trees; city-owned (on municipal property), private (wholly within your property), and boundary (residing on or near a shared property line). Every protected tree has a respective Tree Protection Zone (TPZ), which is prescribed as a radius around the tree-sized based on the calliper of the trunk as set out by the Tree Protection Policy. If your property is in a Ravine or Natural Feature Protection area, the radius will be larger.

If you are proposing construction activity within a tree protection zone, but are intending to keep it, you will require a Permit to Injure. It is important to note that even if a tree is not on your property, the TPZ of a neighbouring tree that extends over your property, will still require a permit. Where a protected tree cannot be maintained, you will require a Permit to Remove. Both permits must be applied for to Toronto Parks and Forestry with a proposed site plan demonstrating the new construction and an accompanying arborist report.

A Permit to Injure
A permit to injure is required to make sure that your construction does not adversely impact the health of the tree above or below ground. If you are proposing demolition, excavation, foundations, projections, or new ground cover in a tree protection zone, you will need a Permit to Injure. The likelihood of being granted a permit to injure depends on many factors:

  • The amount of encroachment into the TPZ
  • The size, species, and condition of the tree
  • Existing obstructions or structures within the TPZ
  • The proposed foundation type and level of work required in the TPZ
  • The presence of major roots in the construction area (typically evaluated with an exploratory dig)
  • The proposed protection measures during construction activity

When applying for a permit to injure, it is important to work with an experienced designer/architect and arborist. Your designer should collaborate with the arborist to determine the best approach to maintaining the tree based on their findings. Your designer and arborist may propose alterations to the building footprint, unique foundation solutions, or other means of mitigating damage to the tree to ensure a successful application. In any case, expect the process to take some time as minor alterations to the proposal or exploratory inspections may be requested before receiving an approval.

A Permit to Remove
If the proposed construction cannot accommodate an existing tree, you can seek a permit to remove it entirely. The likelihood of gaining an approval for this is heavily dependent on the size, condition, and species of the tree in question. If the tree is damaged, diseased, or dangerous, this may increase your chances of success as well. Our team cautions against seeking healthy tree removals unless necessary. Toronto Parks and Forestry has a clear directive from city council not to permit the removal of healthy trees specifically for laneway and garden suites. That said, a tree removal should only be considered a last resort if working around the tree is impossible.

The process for a removal application is identical to an injury application. If the removal is approved, you may be required to plant new trees in its place. Typically, you will be required to replant three trees for every one healthy tree removed. The type of replanted tree(s) can be selected from an acceptable species list provided by the city. The location of the replanted tree(s) must also be approved by Toronto Parks and Forestry based on a site plan provided by your designer, architect or arborist.

On lots where there is limited space available for replanting, the city may accept a “cash-in-lieu” payment for one, two, or all three of the replants required, which is $583 per tree.

Getting Started
The process to securing a construction-related tree permit always begins with securing a new survey and developing a preliminary site plan scheme with your architect/designer and arborist. A typical process unfolds as follows:

  1. Secure a new survey of the property indicating all tree locations/sizes, relative to existing lot lines and structures.
  2. Engage an architect or designer to develop a schematic site plan that considers the tree locations, lot constraints and zoning by-law requirements.
  3. In tandem, engage an arborist to perform a site assessment of the trees in question.
  4. Your architect/designer will collaborate with the arborist to refine the schematic plans. The arborist will provide a final report with recommendations for the work relative to the proposed site plan.
  5. Your architect/designer will apply for a zoning certificate with Toronto Building Services.
  6. The architect or arborist can make the application to Parks and Forestry on your behalf. Toronto Parks and Forestry will also require the zoning certificate to ensure the proposal conforms with the by-laws. Note that Lanescape will prepare and coordinate both the zoning and tree application as part of our basic services.
  7. Expect a response from Parks and Forestry within 30 days of application. For a complex injury application, an approval may be contingent on performing an exploratory dig to confirm the size and location of roots.
  8. If you are proposing an injury to a neighbouring tree, the Parks and Forestry will send a letter notifying the neighbour of the application. The neighbour may not object to the proposal but does have the right to view your plans.
  9. Your designer/architect may make minor alterations to the plans as requested by Parks and Forestry.
  10. Once approved, the tree permit will be issued. In most cases, the actual removal work may not take place until you have a final building permit issued.

In Summary
In every case, our team aims to accommodate healthy, mature trees. While additional density and housing flexibility is critical, it cannot be at a cost to our urban forest. There are many ways in which a tree can be accommodated with clever planning and a deep understanding of the factors to consider. A permit to injure or remove does add time and cost to the process, but it is a necessary step in responsibly realizing your suite and minimizing delays or costs further in the process. As always, we recommend working with an experienced designer that can assist you in navigating what is very much a fluid and situational process. If you are unsure of how a tree may impact your plans for development, send us an email at Our team is your resource!