Why Toronto city staff want to spend $3.2M to plant a quarter of a million native trees

The city's parks and forestry staff will ask council next week to approve a plan that could add as many as 250,000 trees to Toronto's canopy over the next 10 years.

The idea is to halt the spread of invasive species and replace them with hardier native trees, like oak, maple and cherry, they say.

"It's important to plant the right tree in the right place," said Beth Mcewen, manager of forests and natural areas for the city. 

"European Buckthorn is one of the most prolific species that we have in the city now ... and it can take over a forest and stop the reproduction of other species like oaks, maples that support habitat for wildlife."

The city would contract Forests Ontario — a not-for-profit organization "focused on tree planting, forest stewardship, forest education and awareness," according to its website —  to find the hundreds of thousands of native seeds. The organization would then distribute them among its network of nurseries where they'll be tended to maturity — a process that could take up to seven years.

The young  trees would then be planted in more than 80 city parks and ravines. The cost of the plan is about $3.2 million, according to a report to the city's infrastructure environment committee last week, and will last for a decade.

Forests Ontario will collect the native seeds, which will then be catalogued, stored and eventually distributed to one of the half dozen or so of its affiliated nurseries,  according to chief operating officer Elizabeth Celanowicz. It'll be their job to grow the seeds into viable trees and shrubs, which can take four to seven years, Celanowicz says. From there, they'll be shipped to city sites for planting.

"Trying to plant native is the key to a healthy, diverse forest because they're able to adapt to local environments, they're able to handle different climate changes," she said.

"And also with invasive species, a lot of times they out-compete the native species ... and then you lose that biodiversity of that healthy forest."

Forests Ontario uses trained seed collectors, who will gather and catalogue the seeds of particular native tree species, and list where the seeds were found. When the city needs to plant a particular tree in a particular area, it will know exactly which species is being planted and how close to its native habitat that tree is.

At present, when the city decides to target a local forest or field for planting, no-one knows exactly where that tree came from, or whether it's an ideal fit for that particular habitat.

Weeding out invasive species

This latest initiative is a part of the city's wider seed diversity program, which has been ongoing for about 15 years, according to city staff.

It aims to identify which species will grow most effectively in which areas. By gathering and nurturing seeds, the program can  ensure strong genetics in local trees and shrubs, which will help them survive. And those plants can in turn help an entire ecosystem thrive, because native species produce fruits and flowers that are helpful to other native animals and insects.

Kristin Vincent, a natural resources specialist with the city, says this new initiative will produce 15 species of native trees and 16 species of shrubs. 

Another goal is to ensure that invasive species, like European Buckthorn, Dog-strangling Vine, Japanese Hedge Parsley or Garlic Mustard, which have been introduced to the city over the past 70 years, are not the ones getting planted in the city.

'A big problem'

Some nurseries still sell non-native trees and shrubs to homeowners and landscapers.

"It's a big problem," Mcewan said. "It's becoming an increasing part of our management programs ... to try to take away the invasive trees.

"A lot of different species that should be growing here are becoming less and less common."

And by establishing, through Forests Ontario, a bank of native species seeds, the city will always be able to plant the right tree in the right place, Mcewen says, adding she's confident the program can help stem the tide of invasive species. 

"I'm very hopeful," she said, adding that "people are becoming much more aware of how important trees are" to help reduce the impact of climate change.

"It's hard to turn back time to completely change this, but hopefully we'll learn to live with some things and to control others."