By 11 a.m. on Aug. 13, the sidewalk beneath outreach worker Sarah Thomas’s feet was already nearing 46 C and getting hotter. Sunlight, filtered through wildfire smoke from infernos raging hundreds of kilometres away, stained the treeless 300 block of Vancouver’s East Hastings Street an apocalyptic hue.
For the second time in summer 2021, Western Canada was sweltering under a major heat wave, barely two months after the first killed more than 500 people and crippled the region’s emergency response services. The City of Vancouver opened emergency cooling centres and installed mist sprayers on city streets in vulnerable neighbourhoods.
Thomas mopped sweat from her brow and turned back to the growing lineup of people waiting for a bottle of water and a bit of breakfast as the heat bore down on them. Ruby-Marie Dennis, a volunteer from the Tl’azt’en Nation, wrapped ice cubes in wet hand towels, placing them across the necks or against the faces of people already struggling.
“I think it’s over 36 degrees,” Thomas said. “It’s hot out here. There are cooling stations … but a lot of times, people are immobile so we bring our wagons to them.”
Across the city’s Downtown Eastside, other outreach workers were trying to help Vancouver’s most vulnerable survive, handing out free water, sun hats and sunscreen, and checking on people, urging them to go to city-run cooling centres or at least seek out some shade.
But this is one of Canada’s most marginalized neighbourhoods, and shade is hard to come by. Block after block of asphalt and concrete yields little relief from the sun. Some people sheltered in alleys and doorways, anywhere covered, but in concrete jungles with virtually no trees or other greenery, the heat island effect is most pronounced. And while many homes in historically warmer regions of Canada have air conditioning, only one in three British Columbian households are equipped, according to Statistics Canada. For those without, the heat can be worse indoors.
“Last night was so hot, I stayed outside until midnight,” said 63-year-old Vic Dickinson, sitting in his wheelchair waiting for a bottle of water. As bad as the heat was in August, June had been worse.
“It was unbearable,” he said, of his non-air-conditioned, single-room-occupancy unit in a rundown hotel. “We had a fan, but it blew up and they couldn’t get us a new one.” Droplets of sweat streamed down his face as he spoke.
Barely 15 minutes later and five kilometres across town, under the thick, leafy canopy in the tony Shaughnessy neighbourhood (where the average home price is more than $9 million), the sidewalk surface temperature registered only 27.3 C, according to temperature readings taken across Vancouver during B.C.’s August heat wave. Despite the cooling shade this soaring canopy provided, the streets themselves were eerily quiet save for the occasional sound of a gardener, dog walker or other household employee going about their work outdoors.
This unequal distribution of urban forests is replicated in major cities across Canada. Study after study shows wealthy neighbourhoods tend to have far healthier urban forests, with denser tree canopies and more shade, than economically marginalized ones. As climate change worsens, its impacts in urban centres will fall disproportionately on cities’ most vulnerable residents.
Along with helping cool the air, Canada’s urban forests are important assets for reducing the impacts of climate change. Urban forests store roughly 34 megatonnes of carbon and pull an additional 2.5 megatonnes of CO2 from the atmosphere each year, according to a 2014 study.
That’s the equivalent of taking more than 543,000 passenger cars off the road every year.
Earlier this year, Felix Landry, an urban forests expert at the University of Quebec, published a study that examined the urban forests of four major Canadian cities. It reconfirmed the unequal access to urban forests that economically marginalized communities face and found similar inequality faced by multicultural communities.
“This inequality exists in almost every large city on Earth,” Landry said. “For example, cities often invest more in the greening of rich neighbourhoods, even though they are already greener than poor neighbourhoods.”
Richer, more politically connected neighbourhoods also have increased power to oppose certain types of development in their areas, often pushing more intrusive industrial projects or large housing developments into poorer areas, Landry said.
Landry’s study confirmed environmental inequality exists in Montreal, Toronto, Ottawa/Gatineau and Quebec City.
Socially isolated people living in poor neighbourhoods with less access to green space and canopy cover were at increased risk of death amid June’s brutal heat wave, according to an early November report by the B.C. Centre for Disease Control. That lines up with what Landry has seen play out across the country.
“The impact of climate change on urban forests impacts humans in a very deep way, maybe more than any other type of forest,” Landry said.
“We know with climate change, temperatures are going to rise,” he added. “Urban forests shade and help us to cool the ambient air, which can reduce the urban heat island effect by a couple of degrees.”
In a 2014 study, Toronto researchers estimated urban forests saved the city roughly $54 million annually by providing improved water quality and helping to prevent floods, sewer back-ups and other problems for free.
Urban forests also provide what Landry called “cultural services, things that relate to the human way of living.” In the past 10 to 20 years, more research has begun to focus on the impacts urban forests have on physical and mental health.
Children who live in healthy urban forests tend to have reduced rates of obesity. Trees are associated with improved mental health. Neighbourhoods with more and healthier trees tend to see lower crime rates, Landry said.
In a German study, researchers even found the more trees you have in a neighbourhood, the fewer prescriptions for antidepressants that community will see.
As the impacts of climate change get worse, Canadians will experience more heat waves, more August skies choked with wildfire smoke, more trauma overall. Landry said there’s an argument to be made that urban forests won’t just help us weather the physical impacts of this crisis, but the mental, psychological and emotional impacts as well.
“They are good for social cohesion. People go to parks, they play sports, they sit on benches and interact with each other,” Landry said. “That’s a good way to increase social resilience by helping people create links with other people.”
Landry said across Canada, the average tree canopy cover is between 20 and 25 per cent of a city’s total area. In Montreal, it’s around 21 per cent. In the Metro Vancouver area, it’s around 24 per cent. Toronto, with its system of ravines and greenways, has one of the country’s highest average canopy rates, at around 28 per cent.
Connie Pinto, a program standards and development officer with Toronto’s urban forestry department, says that’s due in part to a quirk of history that reveals just how important urban forests are to the prevention of weather-driven catastrophes.
Around 38 per cent of Toronto’s forest canopy exists in its extensive ravine system, areas that have been protected from development since the infamous hurricane Hazel.
During the night of Oct. 15, 1954, the massive storm unleashed huge flooding across Toronto. The city’s rivers flooded their banks — the Humber rose more than six metres — sweeping away bridges, fire trucks, cars and even livestock. An entire block of Raymore Drive was swept away, and 81 people died.
“Essentially, after the disaster, there was recognition that within a municipal boundary, you can’t ignore or treat rivers as if they’re tablelands, because they’re not,” Pinto explained. “They’ve got flash flood issues, there’s erosion and all of that.” As a result, most of the city’s floodplain areas and its ravine system were protected from development forever, allowing the urban forest there to thrive.
While Vancouver’s tree canopy cover falls short of Toronto’s, at around 21 per cent, chief arbourist Joe McLeod said the city is working hard to close the gap by 2050. A year ago, the city reached a key milestone, having planted 150,000 new trees in 20 years. While that success is important, what matters to McLeod more isn’t the number of trees that get planted but how likely they are to survive and thrive.
Total tree-planting targets don’t “look at the system holistically,” McLeod said. Vancouver failed to account for individual tree mortality or trees chopped down for development or infrastructure or devoured by pests like the looper moths that have been destroying hemlocks in the city’s iconic Stanley Park for an unlikely third year in a row.
While a lot of work goes into improving tree canopy and urban forests because they help dilute the unhealthy effects of climate change, Vancouver is also learning how to address climate change risks faced by the forests themselves.
Part of that job involves changing the way the city manages and cares for its existing trees. McLeod said the extremes of the June heat wave forced the city to re-evaluate tree-watering procedures.
As the mercury climbed, the watering program had to adapt, and fast, McLeod said. That meant hiring consultants and contractors to help water trees in addition to city staff working overtime, weekends and extended days.
Addressing the risk to urban forests means recognizing the confluence not just of one particular threat like higher temperatures but the multifaceted way different threats interact with each other. For example, higher temperatures can cause drought conditions, which can make trees less able to fend off pests like bark beetles.
Protecting our urban forests means giving our trees the best possible chance they can to withstand the coming changes to avoid “the kind of cascade of various stresses, whether that be heat stress or environmental stresses or vandalism or people driving into them with cars.”
Hidden from the sun’s glare, Kay (who asked that her last name not be used) swept leaves and other debris from her campsite with a broom. With no home of her own, she set up a tent near the industrial waterfront in Vancouver’s CRAB Park during the second heat wave hoping to take advantage of the shade trees along the park’s periphery and the cooling ocean breeze. Sandwiched between Waterfront Station’s rail yard and the Port of Vancouver’s waterfront, CRAB Park is one of the few green spaces left in downtown Vancouver accessible to underhoused or marginalized people. Kay’s partner, Clint Randen, followed her there. His tiny single-room-occupancy unit in a rundown hotel had become like a sauna, he said.
Between the shade and the breeze, they weathered the heat wave in relative peace, she said.
“We just drank a lot of water and did what you do in the desert: sleep during the day and do things at night when it’s cooler out,” she said.
Before moving into the park, Kay said, she also lived in a single-room-occupancy hotel for about 10 years, but frustrated with the lack of access to more stable housing, she finally gave up. If she hadn’t, she’s not sure she would have been able to survive the heat wave indoors.
“You reach a breaking point where you can’t tolerate it anymore,” she said. “Living like this is better. Unless I’m offered something that’s better than this, I’m here.”
In his studies on tree canopy cover of major eastern Canadian cities, Landry sought to go beyond just confirming the inequitable distribution of trees. He wanted to explore differences between the resilience of existing urban forests in poor or multicultural neighbourhoods and forests in richer areas.
To study this, he tracked the biodiversity of the various urban forests. “A diverse community of trees will be much more resilient to climate effects,” he said. “This is why when you invest in the stock market, you want to buy stocks from a large variety of companies, so if one of them fails, you don’t lose all your money.”
What he found is startling.
Neighbourhoods with poorer citizens, and those more culturally diverse, tended to have fewer trees, and also less variety.
“That means places that have less trees are also more likely to lose them,” he said.
He pointed to Montreal’s experience with the emerald ash borer as an example.
“In Montreal ... something like 25 or 30 per cent of our trees were ash, and when the insect came, it destroyed everything. And then we had a real problem because we didn’t have any more tree canopy,” he said.
“We lost 30 per cent of our trees in a very short time period. If we’d had something like five per cent of ash, when the ash borer arrived, yes we’d have lost five per cent of our trees, but 95 per cent of our forest would have remained.”
Landry said there is a chance to use the destruction wrought by pests like the emerald ash borer as an opportunity. Those trees will all need to be replanted, and focusing on trees that are more diverse and resilient in the face of climate change is an obvious solution.
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