Vacant space model

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)

The Detroit RiverWalk is an urban development project along the Detroit River, designed to reconnect residents with their waterfront and revitalize a historically industrial area. Once characterized by abandoned buildings and industrial debris, the riverfront between the MacArthur and Ambassador Bridges had long been inaccessible to the public. To address this, the Detroit Riverfront Conservancy was established in 2003 to lead the redevelopment of this space.
The RiverWalk currently stretches along a 3.5-mile section, with plans to expand to 5.5 miles, integrating ecological restoration, public access, and recreational opportunities. The esplanade features native landscaping, artistic elements, and amenities, including four pavilions, a custom carousel, and areas for fishing, walking, biking, and inline skating.
Environmental remediation has been a crucial part of the project. In collaboration with the U.S. Environmental Protection Agency’s Great Lakes National Program Office, the Detroit Riverfront Conservancy successfully cleaned up 13,000 cubic yards of contaminated sediment, significantly reducing pollution and contributing to the removal of the Detroit River from the list of the most polluted sites in the Great Lakes. Furthermore, the project also includes greenways, park creation and revitalization.
The RiverWalk is not just a public space; it symbolizes Detroit’s transformation from a Rust Belt city to a sustainable urban environment. It exemplifies the power of public-private partnerships in revitalizing urban areas. The RiverWalk continues to expand, with plans to connect various parks and extend to the Ambassador Bridge, further enhancing the city’s waterfront. Its success was recognized in 2021 when it was named the Best Riverwalk in America by USA Today, cementing its status as a model for urban renewal and community engagement. (Ref. 1, 2, 3, 4)

The municipal real estate company Higab partnered with The Foodprint Lab Architects, an architecture firm specialising in food system design, in a three-year pilot project to create urban farms in three of their properties in Gothenburg. The Foodprint Lab designed the urban farms based on the conditions of each property and connected Higab with potential farmers. The urban farms are located at Slakthuset (an old industrial area), Kviberg (by an empty building undergoing renovation) and Musikens hus (an old building used for music events and a restaurant). The farms are established in unused, mostly grey areas such as parking lots. In all sites, the farming is run by local farming associations; some sell vegetables on site and in Kviberg, there has also been a commercial production of vegetables. Sustainable food production, entrepreneurship opportunities, a nicer and safer environment, and the promotion of biodiversity are highlighted as benefits of the project. In total, about 50 different plant species are found across the locations. The establishment of the urban farms was part of the Grow Gothenburg project within the Sharing Cities Sweden program, which provided some of the funding [Ref. 1-5, 7].

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).

Lafayette Greens is a transformative urban green space and community garden located in downtown Detroit, occupying a parcel of 1720 sqm that once housed the historic Lafayette Building. Following the building's demolition in 2010, the site, situated near Compuware headquarters and the Detroit Federal Building, was re-imagined through a public-private partnership into a productive urban garden (Ref.1, 6). The garden was designed in 2012 for a local software company, Compuware, which after completion gifted it to a local NGO, The Greening of Detroit, in 2014. Lafayette Greens serves as a green oasis in a bustling urban environment, offering city workers, residents, and visitors a space to relax and engage with nature. The garden produces chemical-free fruits, vegetables, herbs, and flowers, and since 2019, has focused on cultivating a certified pollinator habitat, essential for supporting urban biodiversity. The garden also provides educational programming, including classes on pollinators like bees and birds, and the DIG - Detroiters in the Garden series, in collaboration with Fort Street Presbyterian Church’s Open Door program, fostering community involvement and environmental stewardship. (Ref.2)

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 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)

The new 6.5-hectare Anita Berber Park has been created on the site of the former St Thomas cemetery, between Tempelhofer Feld and Hermannstraße. It is named after the dancer Anita Berber, who herself was buried there in 1928. The cemetery was unused and out of use for several years and became accessible to the public through the intervention. (Ref. 3; Ref. 6) The construction period was preceded by a public participation process in which the facilities and design were developed together with the users. The redesign of the space was conducted by a landscape architecture office (Henningsen Landschaftsarchitekten PartG mbB) and financed by the German Federal Government (Ref. 1). The new park, which was planned and financed as a compensatory measure for the construction of the A100 urban highway, increases the quality of local recreation in the densely populated district of Neukölln. (Ref. 2; Ref. 6) An important goal was to achieve high species diversity in the park while preserving its valuable trees and shrubs. The park also offers multiple spots for rest and play as well as a zone for free running dogs. (Ref. 2; Ref. 6)
The park features wooden climbing structures and an old collection of trees with hollows, along with bushes and shrubs. These areas often accumulate rubbish, highlighting the ongoing waste management issues the park has faced since its renovation (Ref. 4).

Lima is grappling with significant challenges driven by climate change, and one of the pressing issues is the shortage of green spaces. According to the PLAM 2035 report, Lima offers only 3.1 square meters of green area per inhabitant, well below the World Health Organization's recommendations (2). Moreover, food insecurity is on the rise, with Peru leading the region in this crisis (4). Compounding these issues is the lack of coordination among state actors tasked with addressing the country's food crisis (2).
In response to these challenges, the Energy Network of Peru (ISA REP) has been running the "Huertos en Línea" project since 2004 in the districts of Villa María del Triunfo and San Juan de Miraflores as part of its corporate social responsibility initiatives (2, 3, 6). This project aims to establish community gardens that promote environmental awareness, reduce pollution in these affected areas (1, 2), provide food for vulnerable populations, and create income-generating opportunities through the sale of surplus produce (1, 6). The gardens are strategically located in power grid easement strips, which are often plagued by encroachment, burning, and waste accumulation—issues exacerbated by poverty, extreme poverty, and weak social organization in these areas (5, 6).
Originally planned with an annual development and growth strategy up to 2011, the project has been extended year by year and has now been active for nearly two decades. Beneficiaries continue to receive technical and material support, and the number of community gardens has grown. In 2019, the initiative expanded to include two bio-gardens in the Trujillo districts of La Esperanza and El Porvenir (7, 9). The project has contributed to improving soil quality, recycling and transforming waste, enhancing landscape aesthetics, reducing burning and waste accumulation, and implementing drip irrigation systems.