CITY NEEDS ITS TREES
Markham St.’s tree canopy is magnificent, substantial enough to mitigate effects of a heat wave.
Trees are not only important to the environment, they can make homes more valuable.
When all else fails, there are always trees. When global warming has turned the city into a melting zone, there are always trees. When planners have turned the city into an unsightly mishmash of intentions and outcomes, there are always trees. When developers have filled the city with buildings hostile to every civic and human need, there are always trees.
But in vast swaths of Toronto, there aren’t always trees.
Though an extensive green canopy in the “old” city and beyond helps make downtown neighbourhoods livable — and beautiful — in postwar suburbs, trees can be harder to find. Indeed, it’s the absence of trees that gives newer communities that strangely naked look so characteristic of industrialscale mass construction.
Yet planting trees is probably the cheapest, easiest and most efficient way to make these places inhabitable and, more emphatically if intangibly, homey. It’s no surprise that studies have measured the connection between trees and property values and found that trees make real estate more desirable and more valuable.
To see why, wander down, say, Markham St. south of Harbord. The tree canopy here is not just pretty, it’s magnificent, even spectacular. It’s also substantial enough to mitigate the effects of a heat wave like the one that had Ontario sweating last week. A friend who lives nearby says he goes out of his way to walk (or drive) along Markham for the sheer pleasure of it.
By contrast, it’s hard to imagine how navigating Bathurst St. north of Lawrence in a heat wave could be more unpleasant. In this version of a city, streets are lined with strip malls that leave no room for trees, or for that matter, pedestrians. Virtually every surface is paved and human activity reduced to two choices — shopping or driving. Green space is leftover space, not much good for trees, anyway.
Trees, of course, need room and time to thrive. That means commitment and a whole lot of patience. Because of that and hostile conditions, the lifespan of a street tree in Toronto is measured in years; which means they stress out and die long before they reach maturity
At the same time, the benefits of trees are numerous; they absorb carbon and water, release oxygen, provide habitat for wildlife and shade for us.
In cities, trees can also serve an architectural function. Think of the rows of London plane trees that line the Champs-Élysées in Paris; remove them and the celebrated boulevard would be just as big but not nearly so grand.
Still, cities and trees have an uneasy relationship, especially at a time of global warming. Conditions on which native plants rely no longer exist. The most common tree in Toronto, the fast-growing Norway maple, is an invasive species planted in large numbers in the late 1960s to replace trees killed by Dutch elm disease. It provided the sort of leafy canopy people craved but had problems. With shallow roots, brittle limbs and weedy qualities, Norway maples crowd out native trees and are easily damaged.
Urban arborists also had high hopes for the ash tree. Then came the emerald ash borer, which experts say will wipe out the GTA’s stock of more than three million ash trees in a few years. Toronto isn’t the only city whose trees have been devastated by disease. Paris’ fabled London planes are threatened by a fungus some fear will wreak havoc on the City of Light.
But as the planet becomes an overheated pigsty, we need trees for more than their esthetic appeal. Though the city is better at planting trees than maintaining them, its declared goal is to increase the canopy, now 27 per cent, to 40. That will require planting 300,000 trees annually.
Even more critical, however, will be figuring out how to help urban trees survive. According to the Toronto Parks and Trees Foundation, the average tree diameter in Toronto is a measly 16.3 centimetres, which makes us a city of saplings.
Ironically, before Europeans arrived, what’s now Toronto was rich in tree life. Carolinian forests mixed with Great Lakes-St. Lawrence woods. In warmer pockets there would have been tulip trees, magnolias, redbuds and pawpaws. On higher ground, 50-metre white pines, red oaks, sugar maples, yellow birch and hemlock prevailed.
What’s left today is largely confined to the ravines and backyards of Toronto where the forest can’t be seen for the trees.