Joint implementation (e.g. tree planting)

Phoenix faces substantial challenges related to extreme heat, air quality, and social inequity (1-11). The Phoenix Tree Equity Pledge, launched in 2021, is a comprehensive city-wide initiative focused on addressing urban tree inequity and reducing the effects of extreme heat, especially in communities most vulnerable to these conditions (1-12). Partnering with American Forests, the country’s oldest conservation nonprofit, the initiative aims to achieve “tree equity” by 2030, ensuring all neighborhoods receive the benefits trees offer (1).
To reach this goal, the city will focus on enhancing tree coverage in underserved neighborhoods through the development of a Residential Tree Equity Accelerator, which plans to plant 20,000 trees across 25 neighborhoods by 2030 (1-12). By utilizing the Tree Equity Score developed by American Forests, the city can monitor progress, identify areas of need, and measure the impact of these projects (2-4, 9, 11).
To foster public engagement, the initiative will collaborate with residents, businesses, and local organizations to support tree-related projects, raise awareness of the benefits of trees, and promote tree stewardship (1, 4, 15). Additionally, the project aims to create green opportunities within the community by establishing supportive policies and regulations for tree planting and care and by creating pathways to green jobs (1, 7-9, 13-14). Recognizing that heat affects communities unequally, the Tree Equity Pledge seeks to increase canopy coverage in targeted neighborhoods, improving air quality, reducing the urban heat island effect, and enhancing overall community health (1, 7-9, 13-14).

The Bahlui Forest project consists of a tree-planting initiative along the banks of the Bahlui River, which flows over a distance of 11 km through Iasi, practically dividing the city in two (1, 2, 6). The project aims to reduce the high levels of air pollution prevalent in the city, increase green spaces along the river and in the urban area, and enhance the aesthetic appeal of the surroundings, thereby improving the quality of life for local residents (1–3, 8, p. 188). The initiative was planned by the Municipality of Iași in collaboration with the Prut-Bârlad Water Basin Administration, the regional authority responsible for the river’s proper management (1–6). Furthermore, the "Ion Ionescu de la Brad" University of Agricultural Sciences and Veterinary Medicine in Iași provided the technical expertise needed to select and plant appropriate species (1–3, 7).
The planting completed in 2024, covers the river section between the Sf. Ioan bridge and the Stone Bridge (3–5). In total, 1,200 native species were planted, including four tree species—Willow, Malin, Red Maple, and Birch—and three shrub species (3–6).
This initiative is part of a broader municipal strategy to revitalize the riverbanks and address key issues (8, 9). Due to its natural geomorphology, the river represents a barrier in terms of accesibility between different parts of the city, and infrastructure and improvements need to be carried out to manage this problem (8 & 9). Therefore the areas around the river are sought to be revitalised to fullfil its touristic and recreational potential, ultimately becoming a green corridor and representing a new axis of development for Iasi (8, p. 344). Improving its green surfaces would also support efforts to increase green space sq.m. per inhabitant in the city, which falls short of the national requirement of 26 sq.m. per inhabitant (8, p. 189).

Baštalište is an organic community garden initiative located in the town of Slanci, some 20 minutes from the city centre of Belgrade (Ref. 3). It is one of the first initiatives of its kind in Serbia, emerging after organizations such as WWOOF Serbia and the Belgrade Flower Festival, along with activists and citizens, united with the goal of growing vegetables for their own needs. Additionally, they aimed to highlight the numerous neglected and abandoned urban spaces in the city that could be repurposed in this manner (Ref.1). Even though more and more people would like to join Baštalište, the community has been struggling to grow beyond their original plot of 1800 m2, shared between some 30 people of mixed demographics (Ref. 3). They have turned to the municipality to provide more such spaces for urban community gardening but their appeals bear little success (Ref. 2,3). Despite their spatial constraints, the initiative remains open to anyone who would like to visit and help while being financed by membership fees (Ref. 1,2,3). The initiative hopes to eventually scale this type of activity, drawing inspiration from the example of Zagreb, where over 2,000 garden communities were established within 2.5 years after the city decided to repurpose its neglected areas (Ref. 2).

The Dublin Urban Rivers LIFE (DURL) project incorporates two interconnected wetlands in Griffeen Park as part of its broader initiative to improve water quality, natural water management and aquatic biodiversity in urban areas. These wetlands were specifically designed as a natural sewage system to treat wastewater from the surrounding areas, addressing a significant environmental issue known as "domestic misconnection." Domestic misconnection occurs when household appliances, such as washing machines, dishwashers, and kitchen sinks, are incorrectly linked to surface water drains rather than the sewage system. This leads to untreated wastewater being directly discharged into local waterways, contributing to contamination.
In the River Griffeen catchment, which includes approximately 12,000 dwellings and associated infrastructure, domestic misconnections are a considerable threat to water quality. The DURL project focuses on identifying and rectifying these misconnected appliances to ensure that wastewater is properly treated before entering the river. This process will not only improve water quality but will also provide flood alleviation and support healthier aquatic ecosystems in the area.
The project is aligned with broader environmental policies, including the River Basin Management Plan 2022-2027, the Water Framework Directive, the Climate Change Action Plan, the Floods Directive, and the draft Biodiversity Plan. One of the key strategies is to use a Geographic Information System (GIS) to streamline inspections for domestic misconnections, making the process faster and more cost-effective.
The constructed wetlands in Griffeen Park, with a standing water depth of approximately 30 cm, are planted with a variety of native Irish species. These wetlands offer a natural, sustainable solution to wastewater treatment, with the potential for similar applications across Europe. (Ref. 2, 4)

Del Nervi Park is a project co-led by the Port System Authority of the Sardinian Sea and the Municipality of Cagliari. Completed in 2021, it transformed a long-abandoned and degraded area on the Cagliari waterfront into a vibrant green space. The two-hectare site surrounds a 1950s industrial building and underwent extensive redevelopment to enhance its structural integrity and convert it into a public park. With a budget exceeding 5 million euros, the project prioritized green investments by creating new pedestrian and cycling paths, along with green spaces featuring local plants, flower beds, grass, and lawns.

Nervi Park is set to become a key destination for leisure, sports, and cultural activities, while also providing the Cagliari community with greater access to green spaces. The environmental and urban renewal efforts aimed to beautify and modernize the area, with future development plans focusing on long-term management and the introduction of commercial activities to further enhance the space
The project faced significant barriers, including prolonged disruptions due to the COVID-19 pandemic, which halted work for about eight months. (Refs. 1, 2, 3 & 4).

Giulia's Farm is the first project launched by the Italian NGO Terre Colte in Sardinia, focused on transforming unused agricultural plots into a productive community garden. Initiated in 2014, the project covers approximately 3,000 square meters (out of 18,000 sqm owned by the NGO). The garden leases 50-square-meter plots to local residents, known as "ortisti," who cultivate the land using organic and natural farming methods. This approach not only revitalizes neglected land but also strengthens community bonds and promotes sustainable agriculture (Refs. 1 & 2).
The project operates on a cooperative model, ensuring that the land remains accessible and productive while fostering a connection between people and the environment. Participants share resources and knowledge, creating a network of mutual support that enhances both social and environmental resilience.
Beyond its agricultural impact, Giulia's Farm aims to preserve Sardinia's agricultural heritage and combat land speculation. By involving the community in farming, the initiative helps protect these plots from being sold for non-agricultural purposes, ensuring they remain dedicated to food production. The project also demonstrates the potential for reclaiming abandoned land, fostering local food production, and building a more sustainable and resilient food system.
Giulia's Farm has gained attention as a replicable model for other regions facing similar challenges of land abandonment and environmental degradation (Refs. 2, 3 & 4).

The Ciénaga de la Virgen is a coastal wetland (cienaga) located on the north side of the border of the city of Cartagena, separated from the sea by La Boquilla's sandy beach. It has a maximum width of 4.5 km, a length of approximately 7 km, a water body area of about 22.5 km², and depths of up to 1.6 m. It is connected to the city's canal system (ref 1). The recovery project of la Cienaga de la Virgen, led by EPA Cartagena, is proposed as a strategy to address the issues affecting the water body, local communities, the economic activities that depend on it, and the ecosystems that regulate the water cycle and provide multiple services, many of them essential, with an integrated and global management approach based on the basin as the unit for planning and resource management (ref 14). Some of the main problems of the wetland are related to illegal settlements on its shore, as well as illicit dumping of waste, pollution by wastewater from the illegal settlements and deforestation of mangroves (ref 4). Key activities include stopping illegal occupation by relocating established families, improving roads, promoting reforestation, encouraging social participation, managing wastewater, and enhancing tidal systems (ref. 1 and 15).
Alonside the EPA, other stakeholders involved include the regional authority "Regional Autonomous Corporation of the Canal del Dique" (Cardique), with jurisdiction in the rural area, and Cartagena Mayor's Office, and the local community, involved in all the stages of the plan thanks to the “mesas de governance” or "governance tables", discussion spaces where different actors participate in the decision-making (ref 2).

The “Sustainable Neighbourhood” project is a pilot initiative led by the Public Environmental Establishment (EPA Cartagena), aiming to achieve environmental management and adaptation to climate change for environmental sustainability in the Boston neighbourhood. The primary objective of the project is to transform these areas into an eco-neighbourhood through activities that promote an ecological culture and raise awareness in the community, thereby enhancing the quality of life in the area, particularly since the neighbourhood is situated adjacent to Ciénaga de la Virgen. This coastal wetland serves as the primary recipient of the city’s wastewater and solid waste. The activities included the restoration of environmentally degraded areas such as mangroves, solid waste collection, environmental education activities, recreational activities, and plastic collection. The project employed a participatory approach, with planning conducted in collaboration with community leaders, public entities, private companies, and other stakeholders (ref 1). Additionally, the EPA conducted awareness sessions on the responsible handling of solid waste, proper water use, and energy service (ref 2). the project seeks environmental management and adaptation to climate change for environmental sustainability, Community leaders participate in these activities with the cooperation and coordination of partners, including Afinia, Guardia Ambiental, Aguas de Cartagena, Comfenalco, IDER, Pacaribe, and others (ref 3).

“The Orchards of the School” is a project led by Antibiotice S.A. through its foundation, "Știință și Suflet" (Science and Soul), which focuses on corporate social responsibility programs. Implemented between 2017 and 2019, employees volunteered to participate in planting orchards in the yards of several schools around the metropolitan area of Iași, including a special education school . The students assisted in planting the orchards and took responsibility for their management afterward.
The primary goal of the project was to instill respect for environmental protection, promote a healthy lifestyle, and cultivate civic spirit within the community among the younger generation. The local authorities prepared the yards for planting, while the Research and Development Station for Fruit Culture in Iași provided standardized methods for proper orchard cultivation.
By 2021 and 2022, the orchards were reported to be thriving and yielding their first fruits for the students (Ref. 1-9).

The Circle Forest project, led by Arboretum Detroit in partnership with Detroit Future City, is transforming a vacant lot the size of a football field in the Poletown East neighborhood into a green space. Once used as a dumping site, the area is being revitalized with 200 native trees, including oak, elderberry, white pine, and juniper. Supported by local groups like Detroit Audubon, Singing Tree, and the US Fish and Wildlife Service, the project aims to improve environmental quality and provide better access to nature for residents. Since 2019, over 120 trees have been planted, with plans to develop a native meadow. This initiative offers a space for recreation and reflection, benefiting the local community, including a nearby nursing home and rehabilitation center. Beyond ecological restoration, Circle Forest fosters connections to indigenous knowledge and respects the wisdom of the original stewards of the land. (Ref.1, 2)