Outdoor enthusiasts regularly note the importance of trees. Even if those who ask to be convinced are rare, there are tools that undoubtedly demonstrate their very great value.
Posted at 11:30 a.m.
These are the tools that Habitat used to count the ecosystem services provided by the trees of Parc Jean-Drapeau.
The carbon sequestration associated with these trees represents $12,744 per year, while the improvement in air quality represents $50,771. The trees in Parc Jean-Drapeau also limit runoff water, a service worth $4,720. We are therefore talking about systemic services of $68,236 per year for a total of 16,963 trees.
PHOTO MARTIN TREMBLAY, PRESS ARCHIVES
By measuring the ecosystem services of trees, citizens who want to preserve a forest can present additional arguments to the authorities.
“The main idea was to inform people and make them aware of the benefits that trees bring us,” says Fanny Maure, director of communications at Habitat. “It seems quite obvious in our urban landscape, but we don’t always realize it. If we have something to remove to build, it’s the trees that will blow up.
” [Les forêts naturelles] have a natural diversity. They present habitats that have been there for years, recalls Mme Moorish. Nature always does things better, we never recreate the natural environment so well once we have destroyed it. It gives very good arguments to knock on the doors of politicians. »
Three academics specializing in the natural sciences, Professors Jérôme Dupras, Andrew Gonzalez and Christian Messier, founded Habitat in 2017 to respond to various requests from municipalities, government institutions or non-profit organizations about management and conservation of natural environments.
This is how Parc Jean-Drapeau wanted to know the value of the ecosystem services of its trees.
Metropolitan influence
“At Parc Jean-Drapeau, we have the reputation of being a major event site with a recreational tourism vocation, but, with the new master plan in particular, we want to rework our positioning and assume the fact that we are a major urban public park. says Kaven Gauthier, public relations manager at the park. “We want to demonstrate, through this study, how the trees in Parc Jean-Drapeau offer many benefits to the well-being of the citizens of the greater metropolitan area. »
PHOTO MARTIN TREMBLAY, PRESS ARCHIVES
Forests, and even urban forests, can provide valuable habitat for many species.
He points out that in the field of sustainable development, more and more comparatives are used to make tangible the socio-economic effect of nature and biodiversity. The Habitat report thus places a monetary value on the ecosystem services of trees, which obviously depend on the species involved, the age of the trees and the place where they are placed.
Different formulas are used to calculate this value: a certain amount for each ton of sequestered carbon, another for each kilogram of pollutants absorbed by the stomata and the foliage of the tree, as well as the cost of treating each cubic meter of runoff avoided.
It makes it possible to bring trees back to the same rank as infrastructure in cities and to say to oneself: “My wastewater treatment plant allows me to filter so much water, my tree allows me to filter so much water, so in the end, it better to plant more trees than to build more sewage plants. »
Fanny Maure, communications director at Habitat
She notes that this is not an exact science and that some factors are difficult to count, such as the well-being of the population. “It still happens,” she says. In the United States, they studied when the country was hit hard by the emerald ash borer. They have seen a truly gigantic number of cardiovascular and respiratory diseases due to the fact that we have cut down a lot of ash trees, entire streets, entire parks. »
PHOTO MARTIN TREMBLAY, PRESS ARCHIVES
Diversity is important when it comes to planting trees. Each species has its own characteristics.
Diversify species
This disaster also showed the importance of diversifying tree species, not only to prevent the ravages of the disease, but also to benefit from the strengths and weaknesses of each species. Some sequester more carbon, but do not support the drought associated with heat islands.
“It is better to plant a bit of everything, to go and find species that are quite different in terms of biological characteristics”, underlines Mme Moorish.
PHOTO MARTIN TREMBLAY, PRESS ARCHIVES
Parc Jean-Drapeau intends to increase its canopy by 30% over the next 10 years.
At Parc Jean-Drapeau, we planted 379 trees in 2021 and we will continue to do so.
“Our goal is to increase the park’s canopy by 30% over the next 10 years,” says Kaven Gauthier. There is a federal program that aims to plant 1 billion trees in Canada: we are going to join in to try to obtain a share of this billion at home. »
While waiting for these new trees, an interactive map on the Habitat website shows the trees that are already at work to improve air quality in the Montreal region.
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