A. All stakeholders benefit fairly from the project

In January 2024, the municipality of Cagliari inaugurated three new green areas in the city, adding five and a half hectares of green spaces for residents to enjoy. These areas are located between Keplero, Avicenna, and Parigi streets, not far from the city center (Refs. 1 & 2).
The primary goal of this initiative is to mitigate the effects of climate change, particularly rising temperatures. The green areas are designed to reduce the city's heat island effect and contribute to carbon sequestration. The planting of new trees will also help maintain ecosystems and improve environmental conditions in targeted areas . Special attention was given to soil quality, with most projects incorporating walkways equipped with drainage systems (Refs. 1, 2, & 4). Additionally, the new infrastructure aims to foster social engagement and attract more citizens, who will benefit from these improvements. (Refs. 1 & 2).
This initiative is also expected to boost the local economy by encouraging the development of small complementary services (Ref. 3). It is part of a larger municipal project co-funded by the EU.

This project aimed to create an urban forest that will grow within Dublin’s Darndale Park, which is popular among students and sports clubs. The objective is to offer the community a green area where they can gather, appreciate nature, and enhance their knowledge about it. The new forest will act as a windbreak for the nearby fishing pond and aims to address challenges related to heatwaves that endanger the lives of young and elderly people. To foster a sense of inclusion and unity, the forest is designed in a doughnut shape, consisting of 3,000 native species like oaks, birch, willow, and hazel, with the trees forming the outer ring (1, 2). This urban forestation initiative is a component of the Uforest project, which is funded by the European Commission and supported by Etifor (environmental consulting company established within the Department of Land, Environment, Agriculture and Forestry of the University of Padua) and Ersaf (an instrumental body of the Lombardy Region) . The Uforest project seeks to enhance Europe's innovation capacity by fostering collaboration among universities, cities, and businesses to develop a novel approach to urban forestry (1).

The Sacred Heart Church, a historical landmark in Detroit's Eastern Market since 1875, faced persistent stormwater and surface flooding issues. The church's parking lot, once marked by cracked concrete and stagnant water, has been transformed through an innovative Green Stormwater Infrastructure (GSI) retrofit. GSI leverages natural processes to manage stormwater, using plants to absorb, retain, and slow runoff. This retrofit, a collaboration between The Nature Conservancy and the parish, stands as one of Detroit's largest GSI projects at a faith-based institution. By introducing bioretention gardens filled with native plants, the project manages runoff from 1.4 acres of impervious surfaces and diverts 1.5 million gallons of water annually from the sewer system. This green space not only mitigates flooding and reduces combined sewer overflows (CSOs) but also provides a cooling effect, enhances community recreation, and significantly cuts the parish's drainage charges by 49%.(Ref.1,2,3)

The himmelbeet is an intercultural, inclusive community garden in Berlin that has been inviting people to garden and harvest their own produce since 2013. The garden offers around 200 raised beds that are communal and can be rented by neighbors, individuals and institutions (Ref. 1; Ref. 3). The project aims to familiarize children and adults with ecology, sustainability and healthy eating and to offer space for social exchange and education, while being inclusive to people with different (dis)abilities and backgrounds (Ref. 2; Ref. 6). The design and implementation of environmental education workshops are a vital part of the work. (Ref. 1; Ref. 6) With its own café and vegetable production, himmelbeet is strongly oriented towards the principles of the economy for the common good. The garden team also looks after other gardens in the city - on behalf of educational institutions, social institutions, housing associations and neighborhoods. (Ref. 1; Ref. 6)
Originally located in Ruheplatzstrasse, the garden moved in 2021 to Gartenstrasse, because of land disputes with the providing land owners and the demand of the space for other social projects. (Ref. 8; Ref. 11)

Lima Verde is one of the pillars of the metropolitan mayor's government plan and is supported by SERPAR. It aims to reforest hillsides, hills, and central berms of metropolitan and local roads, as well as public recreational spaces, to create urban lungs that generate oxygen and scenic beauty for the benefit of the health of all residents (Ref 1, 3). Its goal is to plant one million trees in four years (2022 - 2026) in different parts of North, East and South Lima (Ref 3, 5, 6). This project is being carried out to respond to the increasing problem of urban heat islands that are being generated, especially in the most vulnerable districts where there is no shade due to a shortage of trees (Ref 1, 4). It is therefore focused on areas where the environmental quality is low, where the pollution is high and where there is more danger of higher temperatures (Ref 1, 7).
This programme aims to include youth volunteers, district municipalities, educational institutions, grassroots social organisations, neighbourhood leaders, residents and other entities that favour environmental conservation (Ref 1, 2, 3, 5).

Trénelle-Citron, located north of downtown Fort-de-France and separated by the city bypass, La Rocade, was originally established in the 1940s by Black Martinicans migrating from rural areas. Today, the neighborhood faces significant economic and social challenges. In 2016, young residents from the neighborhood alongside a local NGO launched a grassroots initiative to improve their community. They transformed a former municipal quarry, which had deteriorated into an informal dump, into a thriving shared urban garden, benefiting the local population. This project, based on traditional ecological gardening techniques and the cultivation of native crops, aimed to revitalize Trénelle-Citron—a densely populated area grappling with social exclusion, a shortage of green spaces, and limited economic opportunities for its youth (Ref 2).

The garden, developed on municipal land with guidance from the Ypiranga Martinique NGO, support from the local school, and collaboration from various stakeholders, now plays a vital role in the area. It raises awareness about agroecology, offers socioeconomic opportunities, promotes healthier lifestyles, and fosters social connections among residents. Spanning approximately 1,000 m², the site includes an office, a covered area, tool storage containers, market garden plots, a composting area, and a chicken coop managed by a local resident (Ref 7). In Martinique, such shared urban gardens are increasingly seen as important tools for sustainable development (Ref 5).

Detroit’s neighborhoods grapple with a dual challenge: neglect and flooding. When the city stopped maintaining alleys in the late 1980s, responsibility shifted to residents. However, with limited resources and a declining population, many of these alleys fell into disrepair, becoming symbols of urban decay. This neglect is further compounded by the increasing frequency and intensity of severe storms, which have exposed the city's vulnerabilities in stormwater management, leading to regular flooding.

To address these challenges, the "Alley Activation" project, launched in 2020 by a team of researchers at the UM-Dearborn in partnership with local residents and organizations, seeks to transform neglected alleys into vibrant greenways, rain gardens, and pollinator habitats. The project focuses on cleaning and greening alleys located in 2 neighborhoods namely Littlefield and McNichols. The activated alleys are bounded by Littlefield, Hartwell, McNichols and Outer Drive roads. These roads enclose an area of 141,436 square meters, located in the Bethune community and the Hubbell Puritan neighborhoods. Alley Activation involves clearing blocked alleyways and turning them into inviting, productive spaces that support sustainability goals. These revitalized alleys serve as a "green capillary system," contributing to the city's environmental, cultural, and social well-being. As these spaces are cleared, they offer a fresh opportunity to re-imagine their role and potential within the community. (1,2,3,4,5)

The afforestation project implemented in Lețcani, Iași, is part of Romania's national initiative "We Plant Good Deeds" (Refs. 1-7). Launched by the association EcoAssist and carried out on a voluntary basis, the initiative aims to plant forests across the country (Ref. 8). In Lețcani, the young ecologist group TERIS, together with EcoAssist, involved volunteers to plant approximately 10,000 tree saplings provided by the Forestry Directorate of Iași (Refs. 1, 3, 5-7). The trees were planted on a two-hectare terrain prone to landslides, with the goal of mitigating this hazard (Refs. 1, 3, 5-6). While the project directly benefits local citizens at risk of landslides, it also educated volunteers about the importance of forest cover for community safety and biodiversity (Ref. 4).

The model farm is a small-scale organic vegetable farm according to the principle of a "market garden", meaning little machine use is required [1]. More than 40 different vegetables were grown in an effective growing area of 720 m2, using principles of regenerative agriculture promoting soil health [Ref. 4, 6]. An important outcome is sustainably producing vegetables for schools and care homes in the municipality [Ref. 1-3]. The initial vision was to "showcase both the farming and business model behind a sustainable and successful small-scale farming enterprise" and drive the "integration of regenerative farming practices in the continuous evolution of urban and rural multifunctional landscapes" [Ref. 4, 6]. The model farm offers education and cooperates with a local college [Ref. 1, 6]. The model farm is part of the Climate-KIC SATURN project which aims to reconnect urban and rural areas and address the climate crisis through sustainable food production [Ref. 1, 5, 7].

In the city of Cagliari, in the location of Mount Urpinu, 6400 new trees have been planted. The project, initiated in 2022, sought to restore the area's biodiversity and to revitalize the park for the benefits of the citizens (Refs. 1, 3 & 8). In fact, in previous years, the park has been subject to various environmental and social hazards because of its conditions: the area has been subject to wildfires and abandoned wastes, and with time, it became a gathering point for drug addicts and homeless people, thus becoming unsafe for citizens and especially for children (Refs. 1 & 6).
Therefore, the Metropolitan City of Cagliari decided to reclaim the area and plant thousands of trees of various species (holm oaks, oaks, pine, carob and olive trees) over more than 6 hectares of land (Refs. 3 & 8). The project's goal is to restore biodiversity, mitigate temperatures, decrease air pollution, and increase citizens' sense of community (Ref. 1).