Soil quality improvement

The Grand Parc des Aygalades project involves the creation of a 14-hectare metropolitan park (connecting Aygalades Park with Bougainville Park and François Billoux Park) that will connect the northern neighbourhoods of Marseille to the port located further south (Ref 1). This project is part of the green conversion of Marseille's northern districts, historically among the most disadvantaged areas in France (Ref 1). The Grand Parc des Aygalades project will enhance the city's greenery, reduce flood risks, create cool zones, restore and develop biodiversity, and significantly improve residents' quality of life and air quality (Ref 1, Ref 2). The environmental and social challenges include reconnecting the populations of these neighborhoods to green spaces, services, education, sports opportunities (Ref 2).
The park project includes redesigning urban infrastructure to improve rainwater absorption and reduce flood risks, addressing the issue of impermeable and artificialized soils that exacerbate flooding during heavy rainfall (Ref 1). It also involves renaturing a 17-kilometre-long stream currently buried under railway tracks, improving flood management and rainwater drainage (Ref 1, Ref 4). The project will also convert a heavily degraded former industrial site, requiring the rehabilitation of polluted soils (Ref 1). Additionally, creating green corridors aims to mitigate the heat island effect, particularly severe in these northern districts due to the high concentration of buildings and concrete surfaces, and the lack of green spaces. Public participation will be encouraged through information meetings, thematic workshops, and an online platform for submitting ideas and feedback (Ref 4).

The Oxygen Alley project, developed by the NGO Arboretum Detroit, is a green space located in the Poletown East neighborhood of Detroit. Spanning four formerly abandoned lots, the project, completed in 2023, serves as a significant environmental and community initiative aimed at improving local resilience and promoting environmental justice. Named in recognition of the closure of the Detroit waste incinerator—a major source of pollution for over 30 years—the project replaces a long-abused landscape with a thriving greenway that enhances both the ecological health and social well-being of the area.
Key features of Oxygen Alley include the planting of air-filtering trees and the creation of a shaded greenway lined with wildflowers, benches, and walking paths. This new green space not only provides a recreational area for residents but also functions as a natural air conditioner, stormwater sponge, and wildlife habitat. It addresses the neighborhood’s lack of tree cover, offering shade and cleaner air while helping mitigate the effects of climate change.
The project also underscores the neighborhood's longstanding struggle for environmental justice. The removal of 400 feet of asphalt and the remediation of a polluted landscape highlight the community’s efforts to reclaim and revitalize their environment. Oxygen Alley serves as both a functional green space and a monument to the residents’ victories over the waste industry, symbolizing their continued fight for clean air and livable spaces.
Supported by grants from the City of Detroit, Michigan Department of Natural Resources, and DTE Energy Foundation, among others, the project was brought to life through over 300 hours of volunteer labor. The creation of this greenway not only improves the neighborhood’s walkability but also offers a vision for a more sustainable and equitable future, serving as a model for urban revitalization projects across Detroit and beyond.
(Ref.1,2,3)

Eliseo Collazos is located in the coastal desert ecosystem of the Lomas or ‘fog oasis’, an area that receives less than 10 mm of rainfall per year. Vegetation cover is of particular importance in the hills surrounding Lima, as it provides critical solutions to erosion, landslides and soil degradation in the ecologically degraded ecosystem of the Lomas. However, this ecosystem is facing risks from urbanisation, illegal mining and agricultural practices, resulting in the lack of the delicate mist-fed greenery for which the Lomas are known (2). This has led to increased particulate matter in the air due to exposure to sand and wind, aggravating respiratory diseases such as tuberculosis, which is prevalent in Lima's informal communities (2).
Low-income communities have inhabited this area, forced to migrate from the rainforest, highlands and city to the desert slums (4), who have only been able to settle in these landscapes with little access to resources, prone to disaster risk, little public investment in infrastructure and little access to green spaces (2). As a result, these communities live in poor conditions (1). For this reason, in 2013, the University of Washington, under its Urban Informal Communities Initiative programme (1), initiated a participatory project that sought to address the challenges faced by the inhabitants of this area (1, 2). In a series of participatory workshops, residents identified greenspace and food security as top priorities in their community; the Gardens, Greenspace and Health project responds to these priorities as an initial step towards the expansion of greenspace, agriculture and ecological restoration in and around the Eliseo Collazos community (2, 4).
Although individual families constructed them, the front yard gardens contribute to a shared public realm and community greening (4). The general project also involved the installation of fog catchers and the creation of common recreational spaces (4).

As part of France's New National Urban Renewal Program (NPNRU) and its strategy to enhance urban quality of life, the Urban Integrated Farm in Desclieux was established in 2021, with a particular emphasis on urban agriculture.
This project is implemented by the Centre de Culture Populaire Ypiranga de Pastinha Martinique (CCPYPM or Ypiranga Martinique) in collaboration with the city of Fort-de-France and is located in the socioeconomically disadvantaged Ravine-Bouillé neighborhood. It aims to create a farm on a 2-hectare former military site that previously housed fuel cisterns connected to the French Navy at Fort Saint-Louis. Since falling into disuse in the 1990s, only the reinforced concrete structures remain.
The farm will feature various activities, including a composting zone, a café, a beehive, a botanical trail, a play garden, and areas for crop and animal production. Additionally, it will house a decontamination and materials library and a public living space for community use. Overall, this site aims to serve educational, recreational, and socioeconomic purposes, enriching the local urban ecosystem.
Even though the intervention commenced in 2021 it has encountered several challenges since 2022 due to administrative hurdles. The implementers are currently awaiting temporary authorization to proceed. The primary obstacle remains the development and execution of a comprehensive soil decontamination plan. (Ref 2; 3; 4)

The Färjenäs Agroforestry Garden started in 2013 in the Färjenäs park in Hisingen, Gothenburg. A group of people interested in agroforestry started a study circle on the topic the year before and then formed an association to apply their knowledge in practice. The City of Gothenburg helped the project get started by providing some funding and finding a 2000 sqm spot for the garden on land owned by the city. The Färjenäs agroforestry garden association is run by volunteers, who have planted about 200 different species of trees, bushes and herbs that produce produce. The planting and management of the garden aims to promote soil health and biodiversity. The association received funding from the Swedish Environmental Protection Agency in 2020 and partnered with the Natural History Museum in Gothenburg to further promote biodiversity and wild pollinators, and has partnered with a local beekeeping association to establish a beehive in the garden. The garden is open to the public and invites the public to educational activities and working events such as planting. The association aims to be a meeting place for locals and visitors from all over the city, with different cultural backgrounds and generations. Several courses and educational programs within agroforestry, agriculture and gardening have been held at the garden. [Ref. 1-7]

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

D-Town Farm, located within Detroit’s River Rouge Park, is a landmark urban agriculture initiative led by the Detroit Black Community Food Security Network (DBCFSN). Since its establishment in 2008, this seven-acre farm—the largest in Detroit—has embodied the organization’s commitment to food sovereignty, justice, and security for the city’s African American community. Each year, the farm cultivates over 30 varieties of fruits, vegetables, and herbs using sustainable and regenerative practices. Key operations include large-scale composting, rainwater retention, solar energy generation, and beekeeping, all of which support its ecological and educational missions.
Beyond production, D-Town Farm serves as a community hub. From May through September, it hosts public events that offer educational and recreational opportunities for children and families. The farm also provides hands-on training for aspiring growers through internships and volunteer programs, fostering community engagement and agricultural skill development. Volunteers play a crucial role in daily operations, with ongoing opportunities available throughout the growing season.
D-Town Farm’s mission extends beyond agriculture, serving as a platform for broader advocacy. By challenging barriers to food access, it addresses food deserts with a focus on empowerment and education. The farm supports the local economy by supplying fresh produce to restaurants, farmers markets, and residents, while its health-focused initiatives, such as the youth-centered Food Warriors Development Program, aim to reduce health disparities within the community.
The DBCFSN’s work at D-Town Farm exemplifies a model of community cooperation and self-determination, promoting equity and justice in the food system. By engaging with both local and broader urban communities, D-Town Farm not only strengthens Detroit’s leadership in urban agriculture but also contributes to food justice movements nationwide.
(Ref.1,2,3,4)

The "Parco degli Anelli" is a new green space project in Cagliari, located along the waterfront in the Sant'Elia district. Designed by Portuguese landscape architect João Ferreira Nunes and inaugurated in 2019, the park spans approximately 15 hectares, with over 4 hectares currently accessible to the public. The remaining area will undergo renovation in the next two phases of the project. The park is notable for its open design, free of walls and fences, and its direct access to the sea, making it a unique addition to the city's green spaces (Refs. 1, 2 & 7).
This park exemplifies urban renewal by transforming a previously neglected and degraded area into a green, accessible to all public space. It is part of a broader context of redevelopment of peripheral neighborhoods, in this case the Sant'Elia district.(Refs. 6 & 9).
Parco degli Anelli features flat terrain with numerous pedestrian and cycling paths for individual sports activities, along with expansive grassy areas covering about 27,000 square meters. The park is surrounded by approximately 500 newly planted trees and shrubs typical of Mediterranean maquis, including Aleppo pine, dwarf palm, European olive, and jacaranda.
Future plans for the park include expanding into additional areas and connecting it to the rest of the city via a pedestrian and cycling bridge over the Palma Canal, as well as connecting it to the new waterfront promenade that is being built from Via Roma to Marina Piccola (Refs. 1, 2 & 7).

The Filter Ecosystem project, completed in 2007, aims to improve water quality and enhance the ecological health of the Molentargius wetland area in Sardinia, Italy, also known as the Molentargius Saline Regional Nature Park. This diverse territory includes freshwater basins such as Bellarosa Minore and Perdalonga, saline water basins like Bellarosa Maggiore and Stagno di Quartu, and the predominantly dry area known as Is Arenas.
The Molentargius ecosystem is a crucial European site for various aquatic birds and features diverse flora, including endemic species and endangered plants on the "Red List." It is one of the few globally recognized wetlands of international importance for aquatic birds located entirely within a large urban center, protected as a biotope by the RAMSAR Convention in Sardinia's major urban area. Since the 1980s, it has suffered environmental degradation due to inadequate infrastructure for wastewater management and human pressures.
Implemented by the city of Cagliari, the project employs a phytoremediation technique to supply water to the ponds. This involved constructing a phytoremediation system between the Bellarosa Maggiore and Bellarosa Minore ponds, functioning as a surface flow filter ecosystem resembling a marsh or wetland.
The system enhances natural self-purification processes, promoting prolonged contact between water, organic matter, and plants. This setup creates microhabitats that support microbial flora crucial for purification. The project's primary goal is to treat wastewater from the Is Arenas treatment plant, ensuring that the treated water meets optimal conditions for sustaining the wetlands' biodiversity. Additionally, the project will expand reed bed areas, vital habitats for avian species, and is designed to purify up to 300 liters of water per second to meet the area's needs (Refs. 1, 2, 3).

The project, implemented by the municipality of Cagliari, involves the creation of a new garden in 2021 on Via Eroi d’Italia, in the Pirri municipality, located about 5 km from the center of Cagliari. This initiative is part of a broader effort to reclaim degraded urban green spaces. The garden spans approximately 900 square meters and was previously an unused lot serving as a parking area. Its transformation required substantial groundwork, including soil scarification and leveling, to prepare the area for its new purpose. The garden is now enclosed, with pedestrian access via two gates leading to a paved walkway.
Inside, the garden is divided into two main sections: a children's play area and a landscaped green space. The play area covers about 100 square meters and features durable artificial grass, swings, a spring toy, a universally accessible table, a children's table, benches, and a multi-compartment recycling bin. The green space, approximately 200 square meters, is planted with low-water-use grass and surrounded by drought-resistant plants like albizia, oleander, and lantana, chosen for their low water consumption and resilience to environmental stress. An underground irrigation system, linked to a 5,000-liter water tank, ensures efficient water use.
The remaining 600 sqm outside forms a parking area with 1 disabled space, 2 motorcycle spaces, 1 bicycle rack, and 15 car spaces.
The garden also incorporates sustainable elements, such as LED lighting for energy efficiency and a mural by renowned Sardinian artist Manu Invisible, depicting sunlit forest undergrowth in shades of green. This project responds to citizens' requests and prioritizes resource efficiency by reducing hazardous substances and minimizing waste. The materials used, including recycled plastics, and the selection of plants were chosen to match local ecological conditions, enhancing the garden's sustainability and reducing its environmental impact (Refs. 1, 2, 3, 4 & 5).