Globe Editorial: How tree planting can cool Canadian cities in an era of global warming


Liberal Leader and Canadian Prime Minister Justin Trudeau attends a tree planting with their sons Xavier and Hadrien during an election campaign visit to Plainfield, Ont., October 6, 2019.


There is a vestigial image of Canada – a raw and vast land of forests, lakes and mountains. Forests, especially.

At Confederation 154 years ago, this was true for most people. Less than one in five lived in cities. At the start of World War II, almost half of the population still lived in rural areas.

But that changed quickly thereafter. Today, Canada’s image is reversed: more than four in five people live in cities, and parks are the closest thing to a forest that most of them will see regularly.

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This makes parks like Mount Royal in Montreal and Stanley Park in Vancouver an essential part of Canadian city life. But in recent years, cities have started to understand and invest in the importance of urban forestry beyond the boundaries of the parks themselves. Urban tree canopies are starting to be seen as valuable infrastructure rather than just decorative, a pleasant respite from concrete and pavement.

Toronto has made some of the best strides in growing its urban forest. Its goal is to achieve 40% forest cover by 2050. This is the level at which research suggests that an urban forest begins to significantly reduce temperatures – a natural air conditioning system in a time of global warming.

In 2008, Toronto had an annual urban forestry budget of approximately $ 30 million. A decade later, the budget had more than doubled, reaching nearly $ 70 million. The investment increased the city’s trees to 11.5 million from 10.2 million. The canopy covers up to 31 percent of the city, up from about 27 percent. Toronto estimated the “total structural value of the urban forest” at $ 7 billion.

The gains are significant, especially with the loss of trees caused by the 2013 ice storm and the emerald ash borer. Some losses, however, were self-inflicted. Toronto’s “impermeable land cover” – read: pavements and the like – increased 1.4 percent over the same decade, while plantable space declined 2 percent.

The growth of urban forests is also becoming a priority in other cities. Montreal at the end of 2020 made the planting of 500,000 trees by 2030 a key element of its climate plan. The main focus will be on low-income neighborhoods, which typically have a much more sparse canopy of trees than wealthier neighborhoods.

This trend is easily seen in other large cities such as Toronto, in the northwestern part of the city, and Vancouver, much of the eastern side. The 2018 Montreal heat wave that killed 66 people showed that low-income neighborhoods, lacking the heat-damping effect of an awning, left residents more at risk.

The federal Liberals, as part of their climate change plans, have pledged to plant two billion trees by 2030, in forests and in urban areas.

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The program, which is part of the 2019 election campaign, has been delayed by the pandemic and, like so many government efforts, is working on a later timeline than earlier. The plan is to spend $ 3.2 billion over the next 10 years, but only 40% of that amount is budgeted for the next five years. This year, the initial focus is on urban areas.

Canada is betting heavily on these trees – more than just a respite from the summer heat. The two billion trees are expected to reduce greenhouse gas emissions by 12 megatonnes per year by 2050. Although 12 MT represents less than 2% of Canada’s current emissions, it is also a large number. about the same as all shows in New Brunswick.

When the Liberals announced the plan in 2019, it seemed somewhat fickle. But planting trees is harder than it looks. It takes money and planning. It is a multi-year effort, from growing seedlings in nurseries to preparing, planting and maintaining the site, to keep the trees alive and thriving. The right type of tree is also essential. Norway maples are very common in cities because they grow easily in urban areas, but they are invasive species.

Beyond the emerging vision of the tangible value of an urban forest as infrastructure, trees are simply good for people’s health. “It’s your brain on the trees,” read a headline in The Globe and Mail earlier this year. History has detailed numerous studies that show how trees boost mental health and general well-being. It is the feeling of calm that anyone can savor, whether they are sitting in a forest, under a tree in a park, or along a cool, shady city street on a hot summer day.

Urban forests are part of what makes cities thrive. Continued investments will pay decades of dividends.

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