Ottawa’s urban tree canopy may flatten, decline, before increasing: city staff

Ottawa city staff say its urban tree canopy may flatten, or even decline, before reaching the target of 40 per cent due to a range of challenges.

The city’s urban tree canopy decreased from 21.5 per cent to 20.6 per cent between 2017 and 2022, while staff say that decline could be within the study’s margin of error. Over the entire municipality, the total tree canopy increased from 34 per cent to 36 per cent.

The biggest loses were found in suburban wards where land has been cleared for the construction of new developments. These wards include Stittsville (-11.57 per cent), Riverside South-Findlay Creek (-10.06 per cent), and Barrhaven West (-9.21 per cent).

“With ongoing greenfield and infill development, urban canopy cover may remain flat, or even decline, for the next decade,” a memo from staff reads. “Retaining mature trees provides the greatest short-term benefit, and when removal is unavoidable, successful compensation depends on having adequate space, soil depth, and soil quality to support healthy new growth.”

Staff note that while cutting down a mature tree is an immediate loss for the canopy, planting saplings take years before they grow to contribute to the size of the canopy.

Therefore, staff say policy and regulatory tools need to be put in place to prioritize the tree canopy while working to housing goals and poverty reduction.

“The proposed new Zoning By-law includes requirements to ensure space for trees in new developments while promoting greater supply and density of housing,” staff say. “Continued involvement of forestry staff in development review and the implementation of the Tree Protection By-law will help make these policies effective. Building stronger collaboration with the development industry will be key to striking a balance between a robust tree canopy and a robust, affordable housing supply.”

The city has already implemented some measures through its Tree Planting Strategy to promote early action to replace lost trees. These include:

• a new program to replace 500 lost trees in 2025, scaling up to 1,000 trees annually;
• Plant Your Place, which provides 1,200 larger saplings to residents, targeting priority neighbourhoods;
• an expanded Tree Dedication Program; and
• large-scale planting in parks in partnership with community groups.

West Carleton-March (43 per cent), Rideau-Jock (41 per cent), and College (40 per cent) wards have the largest tree canopies.