Figure 1

2.2 Million Trees are missing in Toronto – taken away from our neighborhood parks and streets.

The missing trees would have removed an extra 10,000 tonnes of carbon from air each year – equivalent to carbon emissions of 7000 cars – and provide direct economic value of $3.9 million (Figure 1)

This is the latest finding from our “Fix the Six” project aimed at reducing climate emissions in Toronto.

“Fix the Six” project was conceived by during the 24 hours #Climathon Toronto (Climate Hackathon)  organised by Climate-KIC on October 28-29, 2016. The team won the First Prize as well as Climate Hero Award.

Using Google Maps, Geographical Information Software (GIS) and I-Tree application, the team calculated the tree cover of 7 Toronto parks and 4 Toronto street (Figure 2).

Figure 2

Over 6400 sample points were taken while carrying out the GIS survey of the Toronto Parks and Streets taken in our sample – giving an error margin of +/- 2%.

Figure 3

Based on the tree cover we calculated their carbon sequestration rate – the rate at which trees absorb carbon from the atmosphere . Excessive carbon emissions is one of the reasons behind global warming and climate change.

Among the 7 parks (High Park, Rouge Park, Dufferin Grove, Trinity Bellwoods Park, Stanley Park,  High Park and the Pierre Elliot School playground) High Park had the highest carbon sequestration rate of 3.1 tonnes per acre while the Pierre Elliot Trudeau school playground had the lowest carbon sequestration rate of 1.32 tonnes per acre. (Figure 3)

Figure 4

Among the 4 Toronto streets – King, Queen, College and Eglinton (sampled between Yonge street and Bathurst street) we found out College street is the “king” of carbon sequestration. College Street had carbon sequestration rate of 1.34 tonnes per acre which was almost double of 0.7 tonnes per acre for Eglinton street (Figure 4).

If High Park and College Street can achieve higher carbon sequestration rates because of their higher tree canopy areas, so can other parks and streets. If all other Toronto Parks and Streets were to maintain tree canopy densities similar to High Park and College Street then we would have at least 2.2 million more trees in Toronto! 

We are missing these trees.

These trees would have filled our neighborhood parks, streets, school playgrounds and open spaces – making Toronto more greener and our air more cleaner while playing an important role in checking climate change. Trees also reduce noise pollution, make cities more livable for children and adults alike, and provide habitat for our shrinking urban biodiversity including bees, butterflies and smaller animals.

Two Key Findings

1. Small Parks are More Efficient Carbon Sinks

Parks located in downtown and densely populated neighborhoods may be smaller but they offer higher carbon sequestration per unit area. For instance, carbon sequestration rate of Queens Park (2.12), Dufferin Grove (2.7)  and High Park (3.7) is higher than the Rouge Park (2.03) which is many times bigger.

We need big parks and conservation areas such as Rouge Park which act as green lung of Toronto and remove massive amount of carbon and pollutants from our atmosphere. But smaller parks are equally important. Due to their higher tree densities they are more efficient in carbon sequestration and improve their immediate environment by removing particulate matter (pollutants) from automobile emissions, providing temperature control and checking rainwater runoff. Tree intensification should also be carried out on School playgrounds, especially on the boundaries to offer more shade and healthier environment.

The city’s climate policy has to put greater emphasis on smaller parks – and more so in view of construction boom we are seeing. Planting space which is razed for building, streets and condos is no longer available for tree planting.

2. Transform Streets to STrees (Street + Trees)

Figure 5

The carbon sequestration rates of Toronto Parks are higher than Toronto Streets. However the higher end of carbon sequestration rates of Toronto streets (for instance of College Street) can match with the lower end values of those of Toronto parks (Figure 5). It makes both trees and parks as useful spaces for implementing carbon reduction initiatives.

All streets in Toronto should have minimum Tree canopy cover standards. And these standards should be met by planting native trees which are efficient in carbon sequestration. We are fortunate in that aspect –  Sugar Maple (Acer saccharum) which is native to Canada tops the list of trees adept at gobbling carbon from the atmosphere. We need more tree lined streets (STrees) in Toronto!

Tree planting and tree protection is one of those activities which can provide immediate benefits to downtown population in terms of providing better air quality, reduce noise pollution, better habitat for urban biodiversity, and make cities more livable for children and adults alike. At present, few people are aware of the role of trees in trapping particulate matter and absorbing carbon – playing an important role in checking climate change.

We plan to continue work on this project to cover more area of Toronto and even expand this ec0-centric and inter-generational approach to other cities in Canada and globally.

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