Private funding by citizens

The Eagle Reef Project was launched to restore the health of Mobile Bay in response to habitat loss and declining fish populations due to the degradation of oyster and seagrass beds [REF 1, REF 6]. Originally planned in 2022 as an Eagle Scout service project by John Shell of Boy Scout Troop 147, the project has grown into a regional environmental initiative supported by Partners for Environmental Progress (PEP), the University of South Alabama’s Stokes School of Marine and Environmental Sciences, and municipalities such as the City of Fairhope [REF 3, REF 4, REF 7].
The project deploys preassembled mini reefs—constructed from plastic and PVC—beneath docks and piers across Mobile and Baldwin counties. These reefs, once colonised by filter feeders like oysters and barnacles, can filter up to 20,000 gallons of water daily and serve as habitats for fish, shrimp, and crabs [REF 1, REF 4]. The initiative aims to improve water quality, sequester nutrients, reduce algae, and restore marine biodiversity [REF 1, REF 6].
The Eagle Reef Project addresses critical coastal hazards, including water pollution, fish habitat loss, and the legacy of environmental disasters such as the Deepwater Horizon oil spill [REF 4]. It combines scientific monitoring, civic engagement, and scalable design to enhance the region’s climate resilience and ecological health [REF 1, REF 6, REF 7].

The Mobile Tree Trail is a nature-based solutions (NBS) initiative aimed at preserving Mobile, Alabama’s urban forest while celebrating its cultural and ecological heritage (Ref 1, Ref 2). First established in the early 1990s by volunteers, the original trail featured 24 iconic trees, selected for their historical significance, environmental value, and beauty (Ref 1, Ref 2). Over the years, some trees were lost to development and storms, and the trail faded into obscurity (Ref 1, Ref 4).
From 2021, the Mobile Tree Commission, with support from The Nature Conservancy, is leading efforts to revive the trail (Ref 3, Ref 6). Activities include reviewing past entries, opening public nominations, and selecting new trees that best represent Mobile’s identity (Ref 3, Ref 4). The project emphasises inclusivity and public participation, welcoming volunteers and local input to shape a trail that evolves with the city (Ref 4, Ref 6).
Mobile faces environmental threats such as hurricanes, urban expansion, and loss of native tree cover (Ref 1, Ref 6). The revitalised trail helps address these challenges by promoting awareness, conserving old-growth specimens like the 300-year-old Duffie Oak, and maintaining vital green spaces (Ref 4, Ref 6).
The Mobile Tree Trail blends education, tourism, and conservation, enhancing urban resilience while telling the city’s story through its trees (Ref 3, Ref 6).

The financial capital of Sri Lanka, Colombo, is the fastest-growing city in Sri Lanka, and as such, it is constantly changing. Most expansions in urban areas are taking place without proper planning, which can cause damage to existing pockets of forests, landscapes and green areas in and around the city (1). The environmental impacts of this rapid urbanisation include increased pollution, increased heat due to the expansion of roads/pavements, tall structures that block out light and wind and reduced biodiversity in fauna and flora (1).
To face these challenges, the Federation of Environmental Organisations (FEO) proposed a city-wide Tree Planting Campaign to create an Urban Forest Strategy in public and private lands in the greater Colombo area (1). The plan is to kick-start the program at the Borella Cemetery as it has a large land area available for planting, specifically 178062 sq meters (3). The project started to be implemented in July 2020 with the seasonal rains (1). This project aims to grow urban trees to help mitigate some of the negative impacts of unplanned and rapid urbanisation, thus making the city more resilient to these changes (1).
The trees that will be planted will be mostly native species and also exotic plants will be selected based on specific requirements (1, 3). It is also planned to have flowering plants and shrubs to encourage butterflies, bees and birds to interspace the trees (1). The new parking space near the Borella Cemetery will also be planted with deep root shading trees interspaced with flowering plants (1).
The project aimed to include a large number of stakeholders including the government, the private sector and the residents of Colombo (1). And they have also reached schools in Colombo and hope to involve environmental associations to further the cause (3).

Herboristerie Créole, established in 2012 in Martinique by Séverine and Rémi Asensio, is a private farm and business focused on cultivating aromatic and medicinal plants, managing all stages of production, processing, and marketing. Situated in the commune of Gros-Morne, the farm draws on traditional Creole knowledge to produce medicinal plants and Creole cosmetics. Spanning 1.8 hectares, it is organized as a forest garden, featuring a diverse ecosystem that includes aromatic and medicinal plants, spices, fruit trees, and tropical flowers. Agroecological practices are central to its operation, with natural mulching from coconuts and green waste, and composting from the forest garden enriching the soil.
In addition, Herboristerie Créole operates a certified organic herbal dispensary in Saint Joseph, specializing in medicinal plants. The dispensary merges ancestral knowledge from the local "Rimèd Razié" tradition—a practice involving the use of native plants and natural remedies for healing, passed down through generations—with modern pharmaceutical standards. It produces a range of products, including herbal teas, infusions, spices, oils, and capsules for pharmaceutical and cosmetic use.
The farm is instrumental in preserving and passing on ancestral knowledge, which was once banned during the period of slavery, while ensuring that its artisanal products comply with dosage and safety regulations. Located at the foot of the Carbet peaks, the farm holds the Biological Farming (AB) label and follows agroecological methods through its "Jardin Créole" approach. It avoids the use of phytosanitary products, aims for zero waste, and implements measures to preserve biodiversity. (ref. 1, 2, 5, 6)

Tirana's urban development has set a new record in 2022, when more than 1.8 million square meters of new buildings were constructed (Ref. 5). This rapid development increased the need for accessible urban green areas. At the Tulla Urban Farm, a wide audience is trained to create those green areas in their yards, balconies and roofs with the added benefit of growing produce for their own needs (Ref. 1,2,5). This practice of food autonomy is deeply rooted in Albanian culture but has been lost in urban settings where concrete has taken over the city (Ref. 1). Tulla Urban Farm addresses this issue by providing an inclusive space for people of diverse backgrounds to come together and experience urban gardening first hand under the guidance of professionals from the Agricultural University of Tirana (Ref. 2,3). In these "urban agricultural schools", workshops, seminars and discussions are held to re-cultivate traditional agro-cultural practices and knowledge that will benefit the participants, many of which are from marginalised backgrounds (Ref. 1, 4). All these activities are facilitated through the rooftop greenhouse of the Tulla Cultural Center, which harbours over 300 plants (Ref.1). As such, Tulla Urban Farm not only provides a space for experiencing and learning about plants but also for social interaction and building a community that also addresses more serious issues such as mental health in a society that faces high rates of unemployment (Ref. 1).
The project had received inital funding from the German GIZ in 2022 and won the Cultures of Resistance Award through which it financed the first two years of its programme and enabled free participation at the urban agricultural school for all participants (Ref. 2,4).

The urban farm of Lak'a Uta is an initiative launched by the NGO Fundación Alternativas, which established the first community garden in Bolivia, located in the city of La Paz at an altitude of 3,600 meters above sea level (1-3). The initial plan was to develop the garden on private land, but since the goal was to create an open space accessible to all citizens, the project eventually sought a public location (3). The subdistrict of Cotahuma granted them permission to use the Lak'a Uta park, an abandoned area rendered unusable by two landslides in the previous year (3). Through voluntary efforts and an investment of 2,800 euros, the land was transformed over three years to accommodate 40 plots of 16m² each, with individual families cultivating a variety of vegetables (3).
Now celebrating its 10-year anniversary, the project adheres to many principles of organic agriculture in an urban setting (5). The area has become a biodiversity hotspot, featuring an artificial pond, 16 wild plant species, and 39 fauna species, including 34 bird species, two types of frogs that provide natural pest control, and three bee species (3-5). Compost is produced naturally using waste management practices and worms (4-5). In addition to edible vegetables, the garden produces medicinal plants, some of which help stabilize the soil and prevent further landslides (3-4). The infrastructure also includes a rainwater collection system (3-5).
Originally, the project aimed to improve access to food, particularly in response to the growing urban population (1-3). Over time, it has also fostered a strong sense of community, while promoting urban gardening through educational workshops and disseminating information nationwide (1-5). It is estimated that 20,000 people have been educated on urban agriculture, healthy eating, and reconnecting with nature (5). The project has also contributed to shaping a local government law supporting urban gardening within the municipality (3).

Over the past two decades, as Phoenix’s population has surged since the 1990s, large expanses of farmland have been paved over to make way for urban development. This transformation has increasingly disconnected the city from its agricultural roots. In 2000, Janna Anderson recognized a growing need for local farms to strengthen their ties with the community and for increased access to fresh, locally sourced produce. With a vision to reconnect the community with its agricultural heritage, she purchased a historic orchard property in southern Phoenix, near South Mountain, in 2011. The property, which included a 1918 adobe home, was transformed into a thriving mixed-fruit orchard.
At Pinnacle Farms, Janna planted over 1,200 trees, including peaches, apricots, and rare Maktoom Dates, which were brought to the U.S. from Iraq in 1910. These heritage crops have unique flavors and textures not commonly found in grocery stores. In 2015, the farm became certified organic, underscoring Janna’s commitment to sustainable farming practices. Her focus is on cultivating varieties that are uniquely suited to the arid Southwest climate, using methods that conserve water and promote soil health.
Janna’s approach to farming also highlights the potential of heritage varieties to support food security in the desert. By growing these rare and resilient crops, she not only preserves biodiversity but also brings attention to how such practices can contribute to a more sustainable, local food system. Pinnacle Farms serves as a living reminder of Phoenix’s agricultural history, a place where fertile soil and sustainable farming practices continue to thrive. The farm embodies the deep agricultural roots of the region, connecting Phoenix’s past to its future and proving that the city’s rich farming tradition is far from lost. (1, 2, 6, 8)

Maya’s Farm is a small, CSA (Community Supported Agriculture) sustainable urban farm located in Phoenix, Arizona, where urban development has limited farmland availability. In 2020 alone, Phoenix lost nearly 200 acres of farmland to urban sprawl, putting farms like Maya’s at risk. The farm faced potential closure until the City of Phoenix intervened, providing funding through the Farm Preservation Program, which established the city's first urban agricultural conservation easement. Maya's Farm strives to inspire a local appreciation for sustainable food and to bring renewed value to local food systems.
The farm’s mission is to provide accessible, fresh, locally grown produce to the community while promoting awareness of healthy, sustainable food practices. Through its CSA program, members receive a weekly produce box and have opportunities to come together, honor food traditions, and share stories over locally harvested food. As a CCOF (California Certified Organic Farmers) certified organic farm, Maya’s Farm is committed to organic practices that exclude GMOs, nurture the soil, foster biodiversity, and innovate growing systems. These methods result in healthy soil and cleaner air, contribute to carbon sequestration, and support critical wildlife habitats.
To broaden educational outreach, Maya’s Farm offers several programs that promote sustainable food practices, including its CSA program, an edible classroom series, and a partnership with Arizona State University (ASU). Through this ASU partnership, students gain hands-on experience by participating in daily farm operations.
Building stronger community connections is another cornerstone of Maya's Farm’s work. The farm collaborates with local restaurants, farmers' markets, and community groups to expand its impact. Maya’s Farm, ASU, and Arizona Sustainability Alliance launched an agrivoltaics project with solar-shaded crops. (2, 9, 11, 13, 15)

The city-wide project Urban Trees for Berlin was launched in 2012 with an ambitious goal: to plant 10,000 roadside trees within five years. This campaign, a key part of the Berlin Senate's Urban Green Space Strategy, is a collaboration between the Senate Department responsible for the environment and Berlin’s district authorities. Initially set to end in 2017, the campaign was extended through 2026.
The project was created to address the loss of numerous roadside trees that were removed due to age, pests, climate stress, and other factors. Limited funds had been available to replace these trees, resulting in negative impacts on Berlin's urban climate, including higher temperatures and worsened air quality, which affect both residents and visitors. The campaign aims to reverse these impacts by securing funding for new trees, restoring greenery to the city streets, and promoting a lasting positive image of Berlin’s urban trees.
The campaign operates on a co-funding model, where individuals, organizations, and companies donate €500 per tree (individually or collectively), with the Senate covering the remaining costs from the state budget (approximately €2,000 per tree). The planting schedule and locations are organized twice annually, with information shared online to keep the public informed.
In 2022, a new assessment of the project’s progress was conducted, commissioned by the Senate to the Arbo-tec office. Around 1,000 of the 3,500 trees planted as part of the campaign by autumn 2022 were evaluated. The selected locations included plantings from all previous construction phases, spanning 12 Berlin districts, with each district having 80 trees assessed from various phases and construction lots. This comprehensive evaluation is intended to ensure the long-term success and sustainability of the Urban Trees for Berlin initiative. (3, 4)

Barranco, the smallest district of Metropolitan Lima, is suffering from serious environmental problems that are affecting its inhabitants. Environmental degradation is a consequence of the increase in large buildings (real estate boom), which reduces green space areas and causes a deficit of vegetation in the district. Additionally, there are high levels of air pollution due to car traffic, which has been accentuated by the lack of green areas in the area, which affects the environmental quality and the population's quality of life (1).
Additionally, the district doesn't have more free public areas where new green areas can be created. Due to these combined pressures, the local government has looked for alternatives, considering private areas, which have a high potential to implement green roofs and vertical gardens, which can contribute to face Climate Change as a mitigation strategy and improve the quality of life (1). The Green Roofs and Green Walls strategy is proposed to build citizen culture, nature appreciation, landscape, and ecosystems (2, 3). The aim is, therefore, to encourage the inhabitants of the district to progressively install green roofs and walls, employing an economic incentive in the taxes paid to maintain public green areas (4).
The programme is oriented to generate environmental benefits such as the reduction of air pollution, acoustic insulation, thermal comfort, and increase of green areas (m2) per inhabitant, and social benefits such as the improvement of the living conditions and health of the inhabitants of the district (1, 3), the promotion of social relations (1), the aesthetic improvement of the city, and the possibility of producing food for self-consumption, as there is support in the implementation of hydroponic systems in the green walls and roofs (1, 3). Its implementation focuses on new, under construction or existing residential, commercial, office or lodging buildings (3).