Improving mental health

The Mediterranean climate in Lisbon, already characterised by low precipitation, has been further exacerbated by climate change. The city faces challenges related to biodiversity loss, urban loneliness, and climate anxiety (1). To address these issues, Lisbon's urban development plans have prioritised the re-naturalisation of urban spaces and the integration of ecological networks. Urban nature is now a central component of the city's Master Plan (2012) and other strategic agendas (1).
It is being developed by the LISGREEN project, which aims to enhance ecological connectivity and mitigate the effects of urban heat islands in Lisbon. By establishing nature-based solutions, it aims to restore forests within the city (1, 2, 3). This project encompasses different strategies, such as the RENATURA pilot project. It is a collaboration with the NGO URBEM and involves active public participation in tree planting and forest maintenance. This initiative aims to educate the community about nature, promote well-being, and mitigate extreme climate events (1), through the creation of urban forests.
The main strategy is to create fast forests using the Miyawaki method, which involves dense planting of native trees, removal of invasive plants, and intensive initial care. This approach accelerates the growth of natural forests within a short period, using native species and reducing the need for watering (1)
The first fast forest was developed in Parque Casal Vistoso within Bela Vista Park, within the Eastern Green Corridor of Lisbon. The park is being underutilised because of the lack of shade (1). Thus, this initiative encouraged volunteers to participate in tree planting and forest maintenance activities (3). The NbS intervention began with a 300m² experimental plot near the Vale da Montanha pedestrian bridge and has since expanded to a new 1,500m² plot on the opposite side of the bridge (2). Over 500 volunteers joined the effort, planting more than 3,800 trees (1)

Public spaces in Colombo are disappearing due to rising land prices, causing infrastructure issues that harm citizens' health, especially in low-income areas (3). One proposed solution to address the problems caused by rapid urbanization is the creation of community gardens, which can at least improve low-income residents' diets and immune systems and address malnutrition (3).
Considering the limited urban space for both citizens and other living beings, the organization Eco-friendly Volunteers decided to create a community garden. The Metta Garden in Colombo (1, 2) aims to bring back urban biodiversity through organic home gardening, generating healthy food for people and creating living space for many other animals and plants (2). Following the Buddhist concept of Metta (loving-kindness to all beings), it promotes walking meditation paths and facilities to experience nature using all five sensory organs (1), in addition to being a place for experiencing loving-kindness for both human and non-human living beings, seen and unseen (4, 5).
It has become a training institute for many stakeholders seeking to grow organic food and earn a better income through the high demand for organic products (2). At the same time, it serves as a biodiversity spot, attracting butterflies, bees, and other forms of wildlife to an urban environment (2).
The area is located in the middle of a semi-urbanized area, on the outskirts of Boralesgamuwa (2, 3). Maintained by a group of volunteers, it features a greenhouse and a plot of land of around 5,000 sq feet, populated with vegetable patches, a butterfly garden, flowers and rare medicinal plants (3, 4). The garden was divided into four sections representing the Buddhist elements: water, heat, air, and solid. Each section features specific plants and designs, like a pond for water, a compost pit for heat, tall plants for air, and a rock garden for solid. The layout follows a mandala design based on permaculture principles (4).

Located in the Lima district of San Isidro - the heart of commercial activity in Peru - the Real Dos Tower is a prime office building in the Centro Empresarial Real de San Isidro. It was inaugurated in 2018, and it is distributed over 23 levels (14 floors and 9 basements) and enjoys a landscaped green roof (1162 m2) at the crown of the building and numerous outdoor vertical gardens at full height (2365 m2) on the three main fronts (1, 4). This project was a finalist in the 2018 Mipim Awards, considered the ‘Oscars’ of world architecture, and stood out for its architecture and design, due to its attributes of innovation and sustainability (2).
This building has managed to create harmony between design and efficient use of resources. It is characterised by a glass façade with colourful movable shutters and symbolic Peruvian designs (2, 3, 6). It has green walls on the three main fronts, four daylight fronts and a roof garden (2). The architect, Jean Nouvel, worked together with ARVE Peru on the overall landscape plans for the Real Dos tower (1, 3).
This is part of the façade remodelling project of the Camino Real Towers in the Real Business Centre, led by the real estate company Grupo Centenario (1, 2, 3, 4, 5, 6). This overarching Project has sought to develop 4,475 m2 of vertical gardens and roof gardens, which have a technified irrigation system to generate efficiencies in water use, meeting the plants' water requirements in the different seasons of the year. Their implementation helps to filter CO2 and renew the O2 in the office complex.
The ARVE group describes these actions as conducive to creating thermal barriers and sound insulation, a better environment for rest, work and entertainment and increasing property value (7)

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).

Biotope City Wienerberg is located in the southern part of Vienna on a 5.4-hectare site that once housed a Coca-Cola factory. It lies at the edge of the Wienerberg recreational area, surrounded by business parks and tower blocks to the west and predominantly detached houses to the east (Ref. 1).
The project embodies the concept of an "urban biotope" (Ref. 2), grounded in the principle that nature's mechanisms of self-regeneration are essential for mitigating the challenges of urban living and climate change. By integrating urban and natural spaces, Biotope City fosters both human-nature connections and social interactions through activities like community gardening. The project’s centerpiece is its extensive green infrastructure, including trees and green roofs, which serve to cool the microclimate, purify the air, enhance water retention, and create carbon sinks while providing habitats for local wildlife. These green spaces aim to improve physical health through cooling effects on hot days and support mental well-being with their calming influence (Ref. 1; Ref. 2).
Biotope City encompasses:
Around 980 flats, including 400 subsidized flats and 200 SMART flats
A school, a kindergarten, and 2,000 square meters of children's and youth playgrounds
600 square meters of community gardens and 3,850 square meters of ground-floor gardens
250 trees, 8,900 square meters of meadows, and 13,600 square meters of green roofs
2,200 square meters of façade greening
The inner courtyards and roof areas are designed for gardening, while façades are greened, and balconies are equipped with integrated plant troughs. Even the spaces between buildings are climate-effective, featuring unsealed catchment and seepage areas to manage water sustainably (Ref. 1).
The project’s implementation took 18 years and involved collaboration among various stakeholders. The concept was initiated by the Biotope City Foundation and funded by eight different investors (Ref. 2).

The Çukurova Arboretum is located 17 km from the city centre of Adana, close to the Seyhan Dam lake. Established in 1997, it aims to conserve and protect plant species and vegetation from the region and those adapted to the Mediterranean climate (Ref. 2,5). Given its location outside the city centre and its proximity to freshwater resources, the Arboretum has been praised as a refuge for relaxation and recreation away from the stress of the city (Ref. 1,3). The area has been established by the Regional Forest Directorate of Adana in cooperation with the Istanbul University, department of Forestry (Ref. 2,3). In 2011 and 2013 new infrastructure was added to the arboretum, including a nursery, main road network connection and irrigation (Ref. 2). Visitors and researchers can access over 1050 ha hosting more than 700 plant taxa in different thematic areas, such as mediterranean vegetation, rose gardens, succulent and cactus areas, medicinal and aromatic plant gardens and an aquatic plants exhibition center which is a special feature to the site (Ref. 2). For research specifically, laboratory projects have been established and nurseries continue to ensure the supply of plant material (Ref.1). Over the years, the Arboretum has been equipped with more elaborate infrastructure and exhebition sites as well as educational material available to visitors (Ref.1,2,4).

The City of Seville has carried out four tree planting campaigns between 2020 and 2024, aiming to meet the goals of its Urban Tree Management Plan for Seville [Ref. 2-7]. The intervention as described here is based on the planting campaigns to date, but as the Management Plan spans from 2019 to 2039, more campaigns can expected in the future. The tree management plan aims to provide guidelines for the planning of trees in the city to maximise their value and minimize conflicts. As part of the process, the current state of the tree population in Seville has been evaluated. The management plan describes the ecosystem services of trees related to climate adaptation, biodiversity and public health. It also identifies challenges and conflicts that may arise due to urban trees and their management [Ref. 1]. The plan has a goal to increase the tree cover in Seville by 5 % over 20 years, which leads to the ambition of planting 5000 trees yearly and the tree planting campaigns over the last years. Between 2020 and 2024, about 1000-5000 trees have been planted each year [Ref. 1-5].

The City of Marseille is engaged in a city-wide project to develop community gardens across its territory. It supports project leaders by providing municipal land and offering a framework along with technical support (Ref 5). Currently, there are 80 community gardens, including 66 shared gardens and 14 family gardens, covering nearly 32 hectares in total (Ref 1).
Marseille aims to provide all residents with spaces for relaxation and socialization in every neighbourhood, particularly fostering shared gardening spaces in neglected land, forgotten squares, building bases, or areas awaiting development. (Ref 1). Community gardens contribute to the city's beautification and support biodiversity (Ref 1) and are founded on values of solidarity, conviviality, and fostering connections between generations and cultures (Ref 4). This initiative also addresses the issue of agricultural land disappearing due to urbanization, while Marseille's many abandoned wastelands offer genuine opportunities to rethink production models (Ref 3).
The city has created a Charter to be signed between the city and garden managers, which can include groups of residents or associations (Ref 2). The charter includes criteria such as citizen involvement, fostering social connections, promoting biodiversity, restoring soils’ health, planting local species, and eco-responsible gardening practices (Ref 2). In return, the city supports the development of these gardens, providing land and offering technical and methodological assistance, including soil analysis and advice on environmentally friendly gardening practices (Ref 2). Additionally, community gardens can serve an economic purpose by creating jobs and enabling the production of healthy and flavorful fruits and vegetables at a lower cost (Ref 2).

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).