Alan Burt December’20

The Sum of All Trees

By Alan Burt

With temperatures cooling off and the trees turning into beautiful colours, many people love this time of year. There are so many things to enjoy after a hot summer. Of course, as with most things, there is a downside. Eventually, if you or your neighbour have trees, you will have to spend several back-breaking hours raking up the hundreds of thousands of leaves that fall. Then you read about some neighbours or a residents’ association opposing the removal of several of these littering monsters by a developer who just wants to build a better home. You may ask, “who cares? I mean what have trees done for me lately?” As it turns out, they have done quite a lot – very quietly.

Here are 10 of the most obvious advantages of trees, especially mature ones:

  1. Heat reduction: Studies show that even low-density trees in a suburban community can significantly reduce the air temperature. In most cities, including Toronto, the areas of highest air temperatures during the summer are those with the lowest tree density. Areas with low tree density are also typically poorer marginalized communities. Trees provide shade for homes, office buildings, parks, and roadways, and cool surface temperatures. They also take in and evaporate water, cooling the air around them.
  2. Air pollution reduction: Trees absorb carbon and remove pollutants from the atmosphere.
  3. Water quality improvement: Trees act as water filters, taking in surface water containing suspended soil and absorbing nutrients into the soil. They also help stabilize soil, reducing erosion.
  4. Energy emissions reduction: Trees reduce energy costs by over $4,000,000,000 a year. Remove the trees, and buildings may require increased air conditioning, which increases the burning of fuel at the power plants, which increases emissions and associated pollution. Trees also act as wind breaks, reducing the cooling effects of high winds and the associated need for increased heating.
  5. Flooding reduction: Urban trees intercept and return more rain to the atmosphere than trees in forested environments. With the delay in runoff, trees can act as an effective stormwater management tool on individual properties and prevent costly basement flooding.
  6. Noise reduction: Trees are used as natural noise deflectors along highways, fences, and between roads and neighbourhoods. They also encourage natural, psychologically beneficial sounds such as birds chirping and wind blowing through leaves.
  7. Protection from UV radiation: Trees absorb 96% of ultraviolet radiation.
  8. Improved aesthetics: Trees and canopy cover improves the looks of any property and may add $1300 to $13000 to its value.
  9. Improved human health: Many studies have found connections between exposure to nature and better mental and physical health.Some hospitals have added tree views and plantings for patients because of these studies, resulting in reduced pain medications and shorter stays. Doctors prescribe walks in nature for people of all ages due to evidence that it lowers blood pressure and stress hormones. Studies have also associated living near green areas with lower death rates.
  10. Wildlife habitat: A broad diversity of birds, animals and insects rely on trees for shelter, food and nesting.

Over the course of 50 years, the value of one tree may be as much as $162,500 US. This total is comprised of $31,500 of oxygen production, $62,000 of air pollution control, $37,500 worth of recycled water, and $31,500 of soil erosion control (Arbor Day Foundation).

The value of trees towards carbon sequestering (removal of excess carbon from the atmosphere to maintain a balance) and other benefits increases with the age of a tree, especially as the surface area of the leaves increases. Consequently, while we should applaud the awarding of the Champion of Trees Award to Toronto, we must also bear in mind that new trees require decades of growth to become appreciable. We cannot afford to remove large numbers of mature trees and rely on the planting of new tree to adequately replace them. With the effects of climate change increasing, we simply do not have the time.

The 2018 Toronto Canopy Study concluded that residential and institutional lands experienced declines in canopy. Overall, the total area of impervious ground cover has increased across the city, which ultimately translates to a reduction in available growing space for trees. We are therefore seeing a reduction in the aforementioned benefits. (

Clear-cutting and development without accompanying tree strategies are sure ways to create legions of activists who will oppose most any development project. Trees can help bring people together. Let them work for you.

If you want to know the contributions and worth of your trees, visit and find out.

Information for this article was derived from