Let’s Talk Trees!

The Importance of Street Trees and Green Infrastructure for Our Health

Toronto is a unique city, full of natural areas including an extensive ravine system, many city parks and green spaces, and biodiverse aquatic ecosystems along our Don and Humber rivers. From the 15km of the Scarborough Bluffs to the nearly 4000 hectares of natural parkland, Toronto reaps many benefits from our green infrastructure. These included mental, physical and spiritual health benefits that are priceless to Torontonians.

Scarborough Bluffs (left) and Moore Park Ravine, Toronto [Credit: Lauren South 2017, 2019]

TREES AND HUMAN HEALTH

Trees and other green infrastructure can have a soothing effect on the human mind and body. Many studies show that trees can help patients in hospitals recover faster. A study in the journal “Science” found that recovery times for patients decreased when their windows faced a natural environment as compared to when they faced a built environment (doi: 10.1126/science .6143402). Trees cool streets and cities down significantly, which reduces the risk of heat-related health concerns. There are many reports of doctors prescribing “nature” to patients with high blood pressure, anxiety and depression.

Most importantly, trees clean the air and provide us with oxygen to breathe!

*Cyclists in High Park, Toronto [Credit: Highpark.org]*

With autumn rolling in, Toronto’s trees are in the spotlight, with leaves changing and creating a colourful blanket on the ground. The scent of fall is in the air, and Toronto’s parks are beautiful locations to visit this time of year. At UHN Energy and Environment, we are lucky to be located a short walk from Queen’s Park, which is sure to look stunning in orange and red in a few weeks time. Autumn is also a wonderful time of year to plant new trees!

*Riverdale Park East, Toronto [Credit: Gerardo Rico, 2013*]

Despite what appears to be a lot of nature, Toronto has only 27% tree canopy cover, as many areas of the city are occupied by grey infrastructure (roads, buildings, sidewalks, etc). But there is some good news! The City of Toronto has a canopy cover goal of 40% by the year 2050, which will spark many new initiatives to plant trees in the city. For example, private residents and business owners can request the planting of new trees on the city property in front of their homes and businesses.

WHAT MAKES A GOOD STREET TREE?

An important aspect of tree planting is knowing what trees to plant! The City of Toronto has a user-friendly brochure (https://www.toronto.ca/data/parks/pdf/trees/street-tree-brochure.pdf). The best trees to plant are native tree species, which originated here in North America, such as maples (black, red, silver, and sugar), tulip trees, oaks, ironwoods, and hackberry trees. Remember, although certain trees are beautiful to look at such as willows, chestnuts, and European ornamental trees, these trees are not native and can do harm to our natural ecosystems if they become invasive.

You can also use the City of Toronto’s handy Habitat tool (https://www.toronto.ca/services-payments/water-environment/trees/tree-planting/) to determine what trees are good to plant. For example, black oak and white pine trees love full sun, whereas sugar maples prefer shady areas. Some trees can grow in many different soil types, whereas others thrive in dry soil.

Now, you may be thinking, “Wow, planting trees is complicated, and I feel overwhelmed!” Do not be discouraged! If you decide to request a tree to be planted in front of your property, the City of Toronto has a wonderful staff of experienced Urban Foresters that can make the decision for you.

HOW TO KEEP STREET TREES HEALTHY

There are healthy street trees with enough room to grow and thrive…

*Trees along St George St., Toronto [Credit: Brown and Storey Architects]*

…and then there are unhealthy street trees, with limited access to resources or no space to grow.

*Queen’s Quay, Toronto [Credit: The Toronto Star]*

Just like people, trees need ample space to grow, and they won’t be able to reach their full potential without a healthy environment in which to live. One of the unfortunate truths about planting trees in an urban setting is space limitation. Especially along roadways, trees are rarely given enough space to spread their roots and thrive. The tree shown in the image below (left) may appear to have enough room to grow for now, but as soon as it reaches a certain size, it will either not be able to continue growing and will die, or it will begin to destroy infrastructure such as sidewalks (below, right).

Two street trees on Elizabeth St., Toronto [Credit: Lauren South, 2019]

TREE PLANTING IN TORONTO

UHN has a few of our own tree-planting initiatives, including a planting at Lyndhurst Rumsey in 2015 (https://talkintrashwithuhn.com/2015/07/15/go-go-go/).

Toronto has many tree planting sessions planned for the near future, here’s a list of them you can find online (https://www.toronto.ca/community-people/get-involved/volunteer-with-the-city/tree-planting-stewardship/tree-planting-stewardship-events-calendar/)

With the smell of fall in the air, school and work are moving at full speed and it’s hard to get out of the City to take full advantage of the beauty of the season. An abundance of urban trees are a wonderful way to capture some of this beauty within the limits of our city.