Compared to their forest counterparts, city trees, and more especially street trees, lead a painful existence. Often treated as nothing more than poles and stressed by extreme conditions – restricted room for growth, poor and compacted soil, pollution, intense heat, lack of water, injuries – their life expectancy is considerably shortened.
Although street trees are a municipal responsibility, you can contribute to their well-being by following these practical tips.
Protecting the trunk
Avoid padlocking your bike to a tree, attaching any objects (posters, decorations) or leaning anything up against it. All those actions can cause injuries that provide entry points for diseases and pests. Injured trees have their longevity reduced and can even die from their wounds.
Careful with garbage bags
Don’t leave your garbage bags in tree squares: when perforated or torn, the products they contain can contaminate the soil.
Damage caused by dogs
Don’t let your dog urinate on the trunk or at the foot of a tree. Urine damages the bark and roots because of its acidity, its high concentration of urea and ammonia, and its salt content. A tree repeatedly peed on by dogs will waste away. And pick up the excrement left by your doggie.
Use of the tree squares
Before gardening in a tree square, get in touch with your borough or municipality to find out what regulations apply. Because they’re so close to the street, all sorts of contaminants can be found in the soil and on the plants. It’s therefore a good idea to avoid growing food plants and to opt instead for ornamental perennials or annuals that are able to resist the difficult conditions – shade and dryness – that are often present under a street tree.
Roots that need air
Avoid raising or lowering the level of the soil at the foot of trees, or compacting the soil, because roots “breathe.” Never add more than 15 centimeters of earth or compost on the roots so as not to asphyxiate them. Also leave a clear area of about one meter around the trunk to avoid the risk of collar rot (base of the trunk).
During heat waves and droughts
Water the street tree in front of your home thoroughly once a week, ideally early in the morning or early evenings. At all times, respect municipal regulations on water use.
Nourish the soil
Spread a little compost annually in the tree square, incorporating it lightly into the soil. The application of a few centimeters of organic mulch (cedar mulch, ramial chipped wood, etc.) will help the soil retain humidity and limit the growth of weeds. The mulch must not be in contact with the trunk.
If a new tree has been planted in front of your home, remove the weeds growing in the saucer.
In case of problems
Do not prune the tree, and do not apply any product to wounds. To report a problem (hanging or broken branch, insects, disease), get in touch with your borough (3-1-1) or your municipality.
Sylvie Maurice and Marie-Josée Bernard, horticultural information staff and authors of this text, wish to thank Guillaume Couture, forestry engineer with Montreal’s Department of Large Parks, Greening and Mount Royal, and Alain Cogliastro, botanist and researcher at the Jardin botanique de Montréal, for their collaboration.