know how to plant trees to support the city of tomorrow

Take the birch, this beautiful tree with a white trunk and elegant foliage. It clearly participates in the beautification of the city. On the other hand, he hates the heat and you can’t count on his shade to cool off. As for its pollens, they have an annoying tendency to attack people with allergies.

The very popular chestnut tree will continue to green the city. It will help city dwellers withstand the heat and heat waves thanks to its climate and air regulation capabilities. It is also a very good support for biodiversity. Gardeners will simply avoid planting it in parking lots where body shops hate chestnuts!

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These recommendations can be found in the Sesame study (Ecosystem services rendered by trees modulated according to the species), a scientific research unique in Europe, carried out for five years by the City of Metz, Metz Métropole and the study center and of public expertise Cerama-Est.

The feedback from Metz gardeners as well as the work of researchers such as Professor Serge Muller, scientific manager of the national herbarium, or Jean-Luc Chrétien, head of the biodiversity division at Cerema, identified 85 trees, shrubs and even plants such as ivy, holly or lavender. Each species is listed according to its capacity to absorb part of the pollution, store carbon, provide shade and freshness (evapotranspiration), provide shelter and cover for wildlife or lichens, maintain the soil , or just be beautiful.

The Sesame I study remained focused on the climatic and landscape context of Metz. In particular, with plantations in Metz near the boulevards to test the depolluting properties of certain trees. Sesame II should bring the number of species studied to 300 and open up to other regions. Paris, Nancy, Thionville, and Saint-Priest, the metropolises of Lyon, Strasbourg and Nantes, Seine-Saint-Denis and Moselle, Cerema, IGN (the National Institute of Geographic and Forest Information) wish collaborate on work, share their data or transpose the messin model. Thanks to these partnerships, and to a budget of at least 120,000 € (City, Metropolis, Cerema, State), the range of services provided by trees should expand. Their role in limiting flooding, their resistance to fire, their ability to fix the soil or help water infiltration, their resistance to spray and their nourishing properties will be studied.

The 85 technical sheets on local tree and shrub species are available on the Cerema and City of Metz websites.

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