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Canadian Urbanism Uncovered

Tree Tuesday: A tree-of-heaven busts-a-move

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Every Tuesday, Todd Irvine of LEAF posts a stop from the Toronto Tree Tours, a collaborative project of LEAF and the Toronto Public Space Committee. The Toronto Tree Tours offers walking tours in neighbourhoods across the city as well as virtual tours on its web site. The aim is to introduce Torontonians to the individual trees in their neighbourhood while telling stories of our city’s ecological and cultural history.

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Dovercourt Park & Neighbourhood Tour: Stop 13

Pushing through the concrete in the front yard of 112 Westmoreland is a large tree-of-heaven (Ailanthus altissima). Native to China, this tree can grow as much as 6 feet per year, with mature trees reaching 70 feet tall and living to be over 90 years of age.

Rarely planted, trees-of-heaven are often referred to as weed trees because their ability to readily reproduce and tolerate harsh conditions allows them to grow in large numbers wherever they take root. Their prevalence poses a nuisance to homeowners and maintenance workers who are constantly pulling saplings out of gardens and cutting them back from buildings and fences.

The seed that this particular tree grew from was carried here by the wind, coming to rest in a crack in the pavement. After a cool spring rain, water running into the crack wet the seed, which germinated and took root in the soil below the concrete before rapidly growing into the large tree it is today. In the fall, this tree will be covered with thousands of seeds of its own, which in turn will fall to the ground and find their way into other cracks around the neighbourhood.

Read more stories from the Dovercourt Park & neighbourhood tree tour . . .

Photo by Dougal Bichan



  1. Arguably it’s another in a regrettable series of bio-invasions – and we can always seem to avoid adding the cost of this harm to the “benefits” of cheaper global trade and goods.
    This cheap stuff just isn’t worth all of the other costs, even though this tree may help soak up the CO2 of our cars, plus quick shade.

  2. Smell bad? What is the above commenter talking about?

    “I love the smell of jizz in the morning…”