Two sites have been chosen for a pilot project in autumn 2021. Adopted in numerous cities around the world, this method is designed to replicate the characteristics of primary forests by planting a wide variety of indigenous species in a dense formation. Planted by means of a participatory approach, these urban micro-forests grow quickly and are home to 20 times more biodiversity, while also helping combat heat islands and cleaning both the air and rainwater.
This autumn, the City of Geneva will welcome Switzerland’s first two Miyawaki forests. The butte Ferdinand-Hodler and the zone industrielle des Charmilles (ZIC) have been chosen by the Parks and Gardens Department (SEVE) to implement this urban micro-forest pilot project in partnership with the Geneva-based company Forêt B. These two sites provide potential areas covering at least a total of 400m², making it possible to plant 1,200 saplings and shrubs with the help of the local population from the surrounding neighbourhoods.
The method developed by the Japanese botanist, Akira Miyawaki and adopted in numerous cities throughout Europe and around the world, makes it possible to create resilient forest ecosystems, foster biodiversity and develop urban ecological corridors, improve the quality of life of the local residents and strengthen social ties by implementing a participatory project.
Dense, fast-growing urban forests
Recognised for its effectiveness in terms of revegetation in urban areas, the procedure is based on a number of particularities. Having prepared the soil with the aim of obtaining the qualities of a soft, rich forest soil by using grain residue from the Brasserie du Mât brewery, located in the ZIC, in order to promote a circular economy, the method recommends planting a wide variety of indigenous tree species in a dense formation, with 3 trees per m² in order to stimulate competition and symbiosis.
Suitable for small plots of land measuring at least 100m², or the equivalent of ten parking spaces, and any type of soil (brownfield sites, land from which tarmac has been removed, green areas, etc.), these micro-forests are characterised by rapid growth (1 metre per year) thanks to their high density and maintenance limited to the first three years of life. If the pilot projects prove successful, further plots currently covered in tarmac – in particular parking spaces – will in turn be converted in micro-forests. A mission to identify potential sites is currently in progress.
“To increase the proportion of green areas over a short space of time in the most densely populated city in Switzerland, it is essential that we explore every innovative avenue open to us,” explains Alfonso Gomez, Administrative Councillor responsible for Finance, Housing and the Environment. At a time when the climate emergency must constantly be at the forefront of our concerns, the Miyawaki method offers numerous advantages in combating and adapting to climate change, combining ecological and environmental benefits with an effective teaching tool. Adopting such an approach will help make the population aware of the importance of protecting biodiversity and our ecosystems.”
Natural areas conducive to biodiversity
Creating micro-forests meets several objectives laid out by the Administrative Council with regard to ecological transition. These natural areas provide numerous so-called ecosystem services, in particular by contributing to combating heat islands, cleaning the air, ensuring sustainable CO2 sequestration thanks to humus-rich soil, supporting improved infiltration of rainwater (5 to 6 times greater than in grassy areas) and creating acoustic barriers. They are also a powerful ally with regard to preserving and fostering biodiversity and biological corridors. Biodiversity is a system which operates in a network and each green area enhances the possibilities for plants and animals to move from one area to another.
By providing a privileged habitat for flora and fauna thanks to the diversity and density of the trees, these forests are, on average, 20 times richer in this respect. Furthermore, they boast a weaker concentration of certain pests, making them more resilient to the effects of climate change. The participatory and pedagogical aspects of the project are essential to the approach. Communities of volunteers will be created under the aegis of the company Forêt B and will be involved in planting and maintaining their forest. By reconnecting with nature, this project will offer citizens the opportunity to reclaim public areas, strengthen social ties and become more aware of the role and importance of these ecosystems and biodiversity.
About Akira Miyawaki
Akira Miyawaki is a Japanese botanist who developed a method of restoring forests in the 1970s. To date, he has been involved in planting more than 40 million trees worldwide, primarily in Asia, thanks to the support of governments, companies and volunteers. It was not until the new millennium that his method was adopted in the temperate climes of Europe. Since 2015, more than 200 micro-forests have sprung up in the Netherlands, Belgium and France.
By observing the characteristics of ecosystems in primary forests, Akira Miyawaki identified the elements to be taken into account in order to imitate and thus create natural forests on any type of soil, even when severely degraded. Akira Miyawaki won the “Blue Planet 2006” award, the equivalent of a Nobel Prize for Ecology, which recognises exceptional efforts in scientific research contributing to the resolution of global environmental problems.
Service des espaces verts
118 Rue de Lausanne
Entrée des véhicules: 120 rue de Lausanne
Article modifié le 20.07.2022 à 11:02