Trees with trunks growing across property lines are called “boundary trees.”
In Ontario, boundary trees are considered common property (i.e., co-owned property) and fall under the legal provisions of the Ontario Forestry Act Section 10. The Forestry Act indicates that it is a prosecutable offense for one co-owner to injure or cut down a boundary tree without the other co-owner’s permission. Under the Act, failure to acquire the consent of a co-owner can lead to a fine of $20,000+ and/or 3 months in prison.

Boundary trees can sometimes lead to disputes between neighbours—especially if one neighbour wishes to remove a tree for construction purposes, a development project, or for other reasons. A recent Ontario legal ruling established protections for boundary trees (including those growing in cities), and clarifies the rights and responsibilities of co-ownership. The information on boundary trees contained in this site is based on this Ruling (2013)—copies of which can be downloaded.
Becoming aware of these rights and responsibilities is an important step toward better stewardship of our trees, as well as avoidance of costly court fees.

The 2013 Boundary Tree Ruling established that the “trunk of a tree” includes everything from the root-collar to the tree’s first branch. If any portion of the tree’s trunk (whether at the base or above it) crosses the property line—it is considered a boundary tree. In many situations, the base of a tree may be on one side of the property line, but at another point, higher up on the trunk, it crosses the property line. It is important to be aware that there are many points on a tree’s trunk that can cross a property line. If any portion of the trunk crosses the property line, a tree can be legally considered a boundary tree and treated as co-owned property. (Photos of boundary trees are available here and can help you to discern your tree’s status as a boundary tree using the criteria established by the 2013 Ruling.)

Note: even if you or your neighbor has obtained a City-permit to cut down the tree, it does not give you/them automatic rights to do so. A City-permit does not cancel out anyone’s property rights in a co-owned tree. (If you read the fine print on a City permit, usually there is a clause to this effect.)

A CAUTION to homeowners and developers about cutting down a boundary tree without a co-owner’s permission!

Since 2013,  home-owners, developers and contractors in Ontario have found themselves in expensive court-cases for cutting down boundary trees without the co-owner’s permission. Fines have ranged from $6,250 to $37,000. Contractors have also faced civil suits for monetary damages. Read the Feb. 3 2018 Toronto Star article by property law expert, Bob Aaron: “Homeowners should always get neighbours’ permission before taking down boundary trees” here.

PROTECTING existing trees is just as important as planting trees:

Sometimes trees can become dangerous and unsafe, and clearly tree safety is something everyone should want and be entitled to. But if your shared, boundary tree is a healthy tree, co-owners should think carefully about preserving it. Why? The size of a tree and the amount of healthy leaf area equates directly to the benefits provided to your household and the community. For example: a tree with a 75 cm diameter intercepts 10 times more air pollution, can store up to 90 times more carbon and contributes up to 100 times more leaf canopy than a 15 cm tree.
Toronto’s “urban forest” consists of over 10.2 million trees, 60% of which are on private property—so private homeowners are the majority stakeholder group in tree conservation. While it’s important to plant new trees, conserving existing trees is also crucial to a healthy urban forest. (Read more on the benefits of trees for cities in Every Tree Counts.)


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Trees growing on private lands are part of a larger ecosystem called the urban forest. All trees filter air, absorb carbon, provide shade against UV rays and provide habitat for urban wildlife. Trees are generous: they are life-giving not only for individual home-owners, but also for the larger neighborhood, including animals in “the hood.”

8 Comments on “Welcome

  1. Hi Hilary,

    Our community has a situation that involves several shared trees that will be subjected to injury or removal due to a re- development.

    Do you have knowledge on how the City of Toronto or Urban Forestry or our local Councillor protects private trees that are shared with the City and is deemed to be removed due to an OMB decision? Can it be saved in anyway?

    Private trees that are shared with neighbors will the City/Urban Forestry give the developer their permit to injure the boundary tree and will the building department permits still be issued if a civil suit is in action? Can we stop permits from being issued to protect boundary trees?

    Lastly, I have been searching for the answer to this question…..Who enforces the Forestry Act? If someone commits against this act does someone ie bylaw officer come out to issue an infraction notice?

    I hope you can help me.

    Thank- you.

  2. The City of Toronto issues permits to injure and destroy trees–but the small print on the permit indicates that the permit-holder must assume all property or ownership-related legal responsibilities. In other words, the permit does not automatically give the developer the legal right to destroy shared trees. This means that the developer who wants to cut down boundary trees has to establish that they have the legal permission of the co-owners to do so. If the trees are boundary trees and co-owned–even though a developer has a City-issued permit–by law they MUST get consent from the co-owners. A common mistake that people make is to think that the City-issued permit gives one person (in this case the developer) SOLE property rights in the boundary tree. Co-owners have the legal right to protect their property, in this case their trees. (My understanding is that the OMB cannot give one property owner SOLE property rights in a boundary/shared tree either.) We went to court to establish this–the issue as to whether or not the City should be issuing permits is a good one. Our lawyers indicated that this would be a interesting legal suit. How can the City issue permits to destroy a shared piece of property (i.e., a tree) without the prior consent of all the owners?
    The Ontario Forestry Act covers boundary trees. The issue of who enforces it is an interesting one: in a recent case in Toronto, a property owner went to court and was successful in having the Forestry Act enforced. Since that time, many boundary trees have been protected. My suggestion would be for you to contact your City Councillor–sometimes they need to be made aware of the recent rulings–and ask them to support you. Ultimately the co-owners of the trees have to go to the developer and assert their shared property rights. This may involve a lawyer, but sharing with the developer this website and a copy of the Ruling is a good start. Many developers are not aware of the Ruling and in many cases they have actually made accommodations to save the trees.
    Hope this helps!

  3. Hi there- do you know where I can find information regarding what laws exist regarding boundary trees in the province of Manitoba?

  4. The information you have provided addresses the cutting down of boundary trees. Does the legislation also apply to the improper pruning (contrary to good arboricultural practice and/or likely to damage the tree) of a boundary tree by one of the co-owners against the wishes of the other co-owner?

    Also, are the plaintiff’s legal costs reimbursed in the event of a decision in favour of the plaintiff? The average homeowner typically does not have the financial means to fight civil suits against developers.

    Your reply most welcome.

  5. The Ontario Forestry Act protects boundary trees from destruction and “injury.” This means that if you can establish that the tree has been injured, then the boundary-tree laws applies. And yes…I know firsthand how expensive it is to mount a civil case! The 2013 Ruling, however, clarified the law. It increased legal risks for developers who do not obey the law. As a result homeowners are now receiving damages, namely in cases of trees being cut down.

  6. Thank you for this informative page! I was wondering if the ruling only applies to “trees”, or would it capture bushes or shrubs as well?

  7. Hi George,
    As far as I know, it applies ony to “trees.” The wording of the Ontario Forestry Act does not inlcude shrubs or bushes.

    All best, Hilary

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