The Foundation for Resilient Urban Greenspaces and Thriving Ecosystems

Midway Milestone of the Tree Seed Diversity Program Reflects the Success of this City of Toronto and Forests Canada Partnership

By Peter Kuitenbrouwer

The City of Toronto motto is “Diversity Our Strength.” These words express civic pride in the city’s great mix of cultures. Today, the motto also describes something else: the growing diversity of trees and shrubs in Toronto’s urban forests.

Greater forest diversity is one of many welcome results of the Tree Seed Diversity Program, a ten-year agreement the City signed in 2021 with Forests Canada (then Forests Ontario), says Raymond Vendrig, Manager of Urban Forestry at the City of Toronto. Under the program, Forests Canada coordinates the production of potted stock, which, is delivered to the City in the spring and fall. Forests Canada works with local seed collectors and nurseries to ensure stock produced for this program meets certain specifications, including local seed sources that are genetically adapted to Toronto’s soils and climate.

“We are getting genetic diversity in species, such as White Pine, Sugar Maple and Red Oak,” Vendrig says. He noted that some plants in the program come from seeds gathered in the GTA. Other trees come from seeds grown in Southwestern Ontario. “It gives you better tolerance to changes in climate,” Vendrig adds. “We are getting trees and shrubs that are grown from the seed zones that are close to the City of Toronto, as opposed to trees and shrubs grown in the southern states or on the West Coast.”

Vendrig believes the arrangement works much better than the piecemeal approach of the past. “Before the agreement, every spring and fall we would have to put out contracts with many small nurseries to find the quantity and species we wanted,” Vendrig says. “It took a lot of staff time, was cumbersome, and you couldn’t get the species or quantities you wanted.” Now the City gets a predictable supply of trees and shrubs tailored to its needs.

Mark McDermid, Seed and Stock Specialist at Forests Canada, works closely with a network of seed collectors and nurseries - including NVK Nurseries in Dundas, Ontario - to target the seed required to produce the desired species. “We have a deep relationship with our seed collectors, many of whom have partnered with us for years and bring knowledge and experience passed down through multiple generations,” McDermid says. “They understand the importance of this work and support us in the Tree Seed Diversity Program.

Even as the program evolves, learning continues. There are challenges with the availability and germination of some species of seeds, McDermid said; he mentioned American Beech, Ironwood and Basswood, which can be difficult to source and propagate consistently. Production cycles – from a seed to ready-to-plant product – can vary, McDermid notes. Fast growing deciduous species such as Silver Maple or White Birch may only take two years to be ready for City staff to plant, whereas White Pine, for example, may take three to four years before it is at the size that the nursery can ship it out. No matter the production cycle, having a long-term agreement in place supports these varying growing regimes. The good news for Toronto: they can plan for their spring and fall plantings, because they know what will be available.

“When you talk with many municipalities with a forest restoration program, most don't operate on long-term growing agreements with growers, they're really relying on what is in the system, and what the nurseries are growing in anticipation of sales,” McDermid says. “So, when a municipality comes to a nursery in September or October looking to purchase stock for the fall or following spring, they're relying on what the nursery has grown on spec. over the last couple of growing seasons. We can confidently plan and have what the City is looking for long term.” He adds: “as this agreement has an annual budget, the City knows what that investment is each year and can plan for it."

Forests Canada tracks the chain of custody details for all the trees and shrubs grown for the program and this information is supplied to the City at the time of shipment. “Each plant receives a batch identification code at the time of sowing that stays with it throughout its life cycle,” Robin Talsma, Plant Production Logistics Manager at NVK says. “This code links to the original supplier, the seed zone or ecodistrict, and other chain of custody details. This information allows Forests Canada and the City of Toronto to trace the provenance of the plants.”

NVK can grow some species within weeks or months, such as Elder, Bblackberry and Ninebark, whereas other species, such as Ironwood, Witch-hazel or oak, take over a year to reach the target heights before being potted into their final container.

“This partnership also challenged our propagation department to expand its knowledge of growing various tree and shrub species from seed—species we previously grew using other methods, such as cuttings,” Talsma added. “We were pleased to see the difference in seed germination and growth. Locally sourced seeds germinate more quickly and evenly than seeds from other suppliers. Seeing this success and ease of germination led us to change a couple of our propagation recipes.”

Talsma said the Tree Seed Diversity Program has inspired her nursery to work with five other nurseries and seed collectors who provide reliable, source-identified, native seeds and plants. Even so, some species remain difficult to supply, with “challenges finding and/or collecting a seed source, low seed viability or germination, high demand and low stock of seedlings, and the restriction of finding material traceable to identified seed zones.”

Talsma adds she is excited about the partnership with Forests Canada and eager to expand this model to other municipalities, noting: “We have seen the interest in native plant material rise over the past few years.” As for the Toronto program, she adds: “This year’s first shipment was over 5,000 assorted source-identified native trees and shrubs, and that was just the first of many for 2026! It has been really exciting to see the shipping quantities grow each year.”

For his part, Vendrig is also talking about expansion of the Tree Seed Diversity Program into other areas of urban forestry at the City of Toronto. This could possibly include what he calls “naturalization of orphan spaces in transportation corridors,” including the circles of space inside highway on-ramps, for example. “Transportation Services is paying contractors to cut that grass,” Vendrig notes. Why not, he suggests, instead plant native trees?

Speaking of the program as a whole, McDermid concludes: “There are many essential components to a 10-year undertaking like the Tree Seed Diversity Program, and it requires a great deal of coordination and long-term planning. Forests Canada is fortunate to have a reliable and established network, together with a comprehensive system in place to meet the complex and urgent need for seed in communities across the country.”