Hamilton's Urban Forest: Why It Matters

Hamilton's urban forest is one of the city's most vital public assets. Trees reduce heat, absorb stormwater, support biodiversity, improve air quality, and make neighbourhoods more livable. But Hamilton's canopy is under pressure. Between 2021 and 2024, canopy cover declined in most wards rather than increasing, moving us further from the city's target of growing coverage from 21% to 40% by 2050.

A critical piece of the solution has long been missing: a city-wide private tree bylaw. Hamilton's Urban Forest Strategy, approved by Council in 2023, identified this as an important priority. City staff recently launched a public consultation process on a proposed ‘Harmonized Private Tree By-law’. This is a meaningful step forward. But in its current form, several key provisions are too weak to deliver the protection the urban forest needs.

The Private Property Problem

Approximately 58% of Hamilton's urban forest canopy is on private property. While the city manages trees on public land, achieving canopy cover targets depends on regulating and incentivizing private landowners as well.

Private trees are often the most ecologically significant. They include the largest and oldest trees in the city, whose size, age, and species diversity generate the greatest ecosystem benefits. They are also the most vulnerable. Without clear municipal protection, private trees can be removed due to landowner preferences, infill pressures, and development activity that falls outside the scope of the Planning Act.

Bill 23 (the More Homes Built Faster Act, 2022) narrowed what the Planning Act regulates, meaning many substantial developments (anything 10 units or less) now proceed with no private tree oversight at all. This proposed bylaw fills that gap. It would apply to individual homeowners, as well as private lands that may be slated for development but where no site plan has been submitted yet, and developments that are not subject to the Planning Act. It is important to note that the bylaw would only apply within Hamilton's urban boundary. While that coverage is important, the proposed bylaw does not go far enough.

Key Gaps in the Proposed Bylaw

1. The Protection Threshold Is Too High

The proposed bylaw only protects trees with a diameter at breast height (DBH) of 45cm or greater. That figure is larger than the threshold used in the existing (pre-amalgamation) bylaws and larger than most comparable municipalities in the GTHA.

The benchmark review conducted by city staff found widespread use of lower thresholds:

• Toronto: 30cm DBH (recently endorsed reducing the minimum protected tree size on private property to 20 cm)
• Burlington: 20cm DBH
• Mississauga: 15cm DBH

At 45cm, Hamilton would become an outlier with the highest regulated tree size in the region. The bylaw would simply not apply to the majority of urban trees. We recommend a threshold of 20cm DBH, consistent with the city's existing woodland protection bylaw and the benchmarking review.

2. Compensation Requirements Are Weak

For removals of four trees or fewer, the bylaw requires only a 1:1 replacement ratio with no specifications on species, size, or verification. Replacing a mature canopy tree with a sapling does not maintain canopy cover. The bylaw is also silent on what species must be planted and does not require a replanting plan or financial security for smaller removals.

We recommend replacement ratios scaled to the size of what is removed, following the approach used by Burlington:

• 2:1 for trees 20 to 30cm DBH
• 3:1 for trees greater than 30cm DBH
• 4:1 for trees greater than 75cm DBH

Higher ratios should apply where removals occur within natural heritage systems or environmentally sensitive areas. Replacement trees should be native species only, and the city should develop an approved Hamilton Native Tree Species List. Minimum planting sizes should be specified: eg. 30 mm caliper for deciduous trees and 125 cm height for coniferous trees.

Financial security, such as a tree planting deposit or letter of credit equal to 120% of replacement planting costs (as is used in Toronto), should be required to ensure compliance. Permit holders should also be required to submit a landscaping and replanting plan, with final compliance check after 2 years.

3. Permit Issuance Criteria Lack Rigour

Section 16 of the proposed bylaw does not specify strong enough environmental criteria for when permits should be refused. The General Manager should not be issuing permits to remove healthy trees and permit issuance criteria need to specify a clear requirement to assess tree condition, location, proximity to environmentally sensitive areas, and the adequacy of the arborist report and replanting plan.

What We Support

The proposed bylaw contains several vital provisions. For example, we support:

• Section 33, which requires permit holders to notify the city when replacement trees are planted and allows for an inspection at least one year after planting.
• Section 20(h), which requires permit holders to post the permit in a conspicuous location visible from the street before, during, and after tree removal. This increases transparency and reduces community confusion.
• The exemption for invasive species as defined under the Invasive Species Act, 2015. The Invasive Species Act regulated list only includes one tree at this time - the Tree of Heaven. We agree with keeping it tightly scoped. Expanding exemptions to include a broader range of invasive species, for example the trees on the Ontario Invasive Plant Council list, such as Norway maple, would seriously undermine the bylaw by exempting Hamilton's most prevalent tree species. The broader list of invasive trees identified by OIPC should be used to determine tree species that are not acceptable to meet tree replacement requirements.  
• Minimizing the costs to individual homeowners is an important consideration and we suggest this could be achieved by including equity provisions modelled on Toronto's approach, such as waiving application fees for not-for-profit housing providers or low-income homeowners.

The Path Forward

A city-wide private tree bylaw is long overdue in Hamilton. The proposed Harmonized Private Tree By-law creates a foundation. But a 45 cm DBH threshold, weak compensation requirements, and vague permit criteria will not deliver meaningful canopy protection. Without strengthening these provisions, the bylaw risks becoming a permitting exercise rather than a conservation tool.

Hamilton set a target of 40% canopy cover by 2050. Reaching it requires protecting trees before they come down, not just planting saplings after the fact. Council has the opportunity to pass a bylaw that reflects that ambition. We urge them to take it.

Monumental Collaboration for Monumental Trees

Over the past several weeks Hamilton tree people have been meeting and sharing information about the proposed tree bylaws and tree protection changes. To find out more or join this group, please contact us at [email protected]. 

The recommendations shared above were developed in partnership with Lesia and Katie - the team at Tropos - and after reviewing the Harmonized Tree Bylaw recommendations of the Hamilton Naturalists’ Club and Save Our Streams. 

You can review the Save Our Streams recommendations here: https://www.saveourstreamshamilton.org/private-tree-protection-bylaw

Attend the Monumental: Protecting Urban Trees event, co-hosted by Tropos and Green Venture at The Revival Art Store on June 4, 2026 from 6-8pm.

More information on this event and registration here: https://www.greenventure.ca/protecting-urban-trees

Stay tuned for updates and opportunities to learn how to delegate or submit a written delegation when the final proposed bylaw and staff report is presented to Council for approval.  

Additional Resources and Links from the City of Hamilton: 

Engage Hamilton page: https://engage.hamilton.ca/harmonizedprivatetreebylaw

Staff Report on Draft Harmonized Private Tree By-law and Proposed Updates to the Urban Woodland By-law, Woodland Conservation By-Law, and Tree Protection Guidelines: 

https://pub-hamilton.escribemeetings.com/filestream.ashx?DocumentId=483653

Draft Private Tree Bylaw: https://pub-hamilton.escribemeetings.com/filestream.ashx?DocumentId=483654

City of Hamilton Public Engagement Presentation: 

https://www.hamilton.ca/sites/default/files/2026-03/privatetreebylaw-openhouse-presentation-march2026.pdf