A new plan that aims to promote more native trees in Canada’s greenest city may have trouble gaining ground.
As it turns out, planting B.C.’s native trees – which are often large and best suited to roomy forests – may not be so easy in Vancouver, especially along city streets.
The city’s first urban forest management plan, due to be released next spring, will provide details about the 150,000 trees the city has pledged to plant by 2020. That figure is roughly equal to the number of trees currently lining Vancouver’s streets.
“We’re hopeful that in large part those will be native trees,” said park board commissioner Niki Sharma. “The city has a goal to become the greenest city in the world.”
However, when it comes to local species, arborists have few options to choose from, says Douglas Justice, the associate director of UBC’s Botanical Garden.
“Our trees tend to be very large, especially the conifers,” he said. They can also be vulnerable in heavy winds.
Justice says street trees need to be able to handle difficult growing conditions, like compacted soils and cramped roots. This means that B.C.’s native species often get passed up for cultivated exotic varieties.
Park board records show that the majority of the nearly 2,000 trees planted along city streets between January and August of 2013 were of Asian or European origin. Less than 10 per cent are native to British Columbia.
In recent years, other Canadian cities have taken measures to actively promote native trees in the urban landscape.
Toronto and Montreal offer native trees to local residents at reduced prices. The city of Ottawa’s website provides detailed lists of native flowers, shrubs and trees to encourage people to grow local.
But Justice argues that the forests in eastern Canada provide a wider selection of city-friendly trees.
“In eastern North America, you’re in the middle of the hardwood forest and the diversity of plants in that hardwood forest is much greater.”
The exotic trees on the streets of Vancouver
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A lack of suitable local species is not the only reason that exotic trees have been favoured in Vancouver.
Bill Harding, the city’s director of parks, says that Vancouver’s warm, wet climate makes it an ideal spot to grow ornamental trees.
“We can grow a more diverse forest than some of the other [Canadian] cities can,” he said. “There are some very good trees that aren’t native to B.C. but they fit in very well.”
But not everyone agrees that Vancouver should plant exotic trees simply because they will grow.
From the blossoming cherries to the English Bay palms, Vancouver’s trees have long been chosen for their aesthetic appeal, says Ross Waddell, a founding director of the Native Plant Society of British Columbia.
“You could use so many different species here, because of the climate,” he said. “It creates diversity and that can be healthy, but … there’s no ecological rationale being used.”
Waddell acknowledges that Vancouver faces some unique challenges when it comes to growing local plants. Still, he says, it is important for urban residents to feel connected to the natural environment.
“I think it’s important children understand where they live,” he said. “It’s about sustaining native ecology in urban environments.”
Even if city streets are not the best place for local trees, Sharma believes that there is still a large potential for promoting that native ecology in Vancouver.
“There are good opportunities in a lot of park spaces to actually create a whole native canopy.”
Sharma is part of the Vision Vancouver team that created the city’s first Greenest City Action Plan. One of the targets of that plan is to plant 150,000 new trees on streets, in parks and on private property.
Douglas Justice also agrees that there is a place for native trees to be planted in Vancouver.
But he holds firm to the idea that the diversity and resilience of the urban forest should not be sacrificed in the process.
“You need to have plants that are going to survive.”