Increased feelings of happiness and contentment

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)

The schoolyard at Reginhard Primary School in Reinickendorf faced persistent challenges, often becoming unusable due to poor drainage. After rainfall, water would pool, leaving the yard submerged and inaccessible to the 400 primary school pupils. Even in dry weather, the schoolyard was far from ideal: a lack of play equipment made it uninviting, and in summer, the area became excessively hot, offering little comfort or shade. Both children and the school community, including teaching staff and parents, voiced a strong desire for improvement.
Adding to the urgency for redesign, Berliner Wasserbetriebe imposed a discharge restriction, requiring rainwater to be managed on-site. This led to a comprehensive transformation of the school grounds. Large areas were unsealed, allowing water to seep naturally into the ground. Underground seepage systems were installed to enhance drainage, and the redesign introduced green spaces, a school garden, and near-natural play and exercise areas. These changes not only resolved the flooding issue but also created a more inviting and sustainable environment for students.
The focus on ecological and sustainable design improved the microclimate, providing cooler surroundings and enabling outdoor breaks filled with activity and fresh air. The redesign transformed the schoolyard into a vibrant space that meets the needs of both children and the environment.
This project was funded by the Berlin Programme for Sustainable Development (BENE Umwelt) and financed by the European Regional Development Fund (ERDF). (Ref. 3; Ref. 4)

The John Michuki Memorial Park was transformed from a vast dumpsite in 2008 and established in honor of John Michuki, the Environment Minister during the Kibaki administration, in 2012. Michuki garnered admiration and accolades for his enthusiasm and determination to clean and preserve the environment (Ref 1, 2). Situated along the Nairobi River, the park serves as a historically rich recreational facility (Ref 3).
However, several issues arose after the park was transferred to the county administration in 2013 (Ref 2). A section of the Nairobi River flowing through the park experienced severe environmental degradation due to illegal discharges and poor waste management, negatively impacting the riparian ecosystem and biodiversity (Ref 4). Additionally, the park became a refuge for drug users, street children, and thieves, with stray dogs posing safety threats in the area (Ref 1, 2).
As the first project within the Cleaning Up Kenya Campaign, the restoration of Michuki Memorial Park was launched in 2020 by the government (Ref 5). The park is now managed by the Kenya Forest Service (KFS) following a directive from the national government (ibid.). With funds from the treasury, a perimeter fence was erected, a 2.4 km walkway was constructed, and 4,200 seedlings and 6,357 indigenous trees were planted, along with the establishment of a nursery (Ref 1, 6). A total of 20,000 tons of solid waste were removed (Ref 6). Additionally, a community forest association was formed to ensure community engagement (Ref 2).

The Köprüköy Mosque in Adana, commonly named "green mosque", is one of a kind in Türkiye (Ref. 2,5). Its building and minaret are almost entirely covered by poison ivy and appear in vivid green colour from afar. Founded in 1929, it had to be remodelled in the early 60s as it couldn't sufficiently accommodate worshippers in the growing district. The mosque was then entirely built and rebuilt by the community, with its maintenance overseen by the mosque's protection association (Ref. 4). In the 70s, the ivy was planted and has since helped to protect the building from environmental stressors and keep visitors inside the garden and mosque cool during the summer heat (Ref. 4,5,6) Furthermore, the mosque’s well-maintained garden, home to around 280 species, is adored by local, national, and international visitors and tourists, as well as the media (Ref. 1,3,7). Frequent maintenance and rotation of the garden's flowers keep its appearance and function intact, one of which is the profound impact on visitors’ well-being, with many praising the unique atmosphere of the mosque that evokes peace, comfort, and spirituality (Ref. 1,3,4).
During COVID-19, the mosque could only host worshippers during praying hours, after which it quickly continued to bring people back together to garden, rest and socialize throughout the day (Ref. 1).

Rike Park, centrally located on the riverbank of the Kura River, is one of the most recently developed Parks in Tbilisi. It was announced by the city hall in 2009 with the aim to increase the amount of accessible green space in the densely developed city center and stretches over an area of 7.5 ha (Ref. 1). Being the only location in the city where such a project could have been developed, it also serves as a pedestrian-friendly way to cross from the newer part of the city towards the old town via the adjacent "Peace Bridge" (Ref. 1,3). Next to its various amenities for recreation, the park has become a symbol of national identity through its design (Ref. 2). From above, one can identify the grid abstraction of the map of Georgia while in the center of the park lies a large Rose shaped mosaic, making a symbolic reference to the Rose Revolution (Ref. 3,5). Furthermore, Rike Park hosts several cultural festivities and artistic performances that invite the public to interact and socialize (Ref. 4).
Despite the park's success, its development has been criticised due to the city hall's exclusion of public consultations and transparency (Ref. 1).

In 2023, the municipality of Cagliari initiated a project to transform 50 school gardens into vibrant, multifunctional outdoor spaces that enhance education and recreation. Co-funded under an EU program, this initiative aims to create environments where students can learn and play outdoors, taking advantage of the city’s favorable climate. The gardens are being upgraded with new features, such as trees, educational vegetable plots, diverse plant species, playground equipment, and furniture, to provide versatile spaces for learning, sports, and play.
Automated irrigation systems are being installed in each garden, conserving water by adjusting based on soil humidity and detecting leaks. This technological upgrade ensures efficient maintenance of the green spaces.
Overall, the project seeks to enrich the educational experience by integrating nature into daily school life. It aims to promote students' physical and psychological well-being through more opportunities for outdoor learning and activities, fostering a connection with nature, and improving the overall quality of the school environment (Refs. 1, 2, 3, 4 & 5).

The Africatown Connections Blueway project aims to create a recreational water trail by linking 14 culturally and historically significant points along a 10-mile route (Ref 1). Central to this initiative is the preservation of Africatown's rich heritage and natural resources. The project seeks to reconnect residents of Africatown, descendants of the original founders of this self-governing community, which maintained a strong sense of African cultural heritage, to waterways that were historically vital for food, transport, and spiritual practices (Ref 1). By restoring access to these waters, the community can address both environmental and social issues, promoting eco-tourism and business growth while safeguarding cultural heritage (Ref 2). Local leaders emphasize the environment’s role in healing the community and preserving history, highlighting how this initiative can provide economic opportunities and improve quality of life (Ref 2). The project seeks to address the environmental injustices that Africatown communities have endured for decades. The area surrounding Africatown has long been dominated by harmful industries, including aluminium plants and paper mills, which have heavily polluted the water and restricted residents' access to it (Ref 1). With support from the National Park Service and contributions from Mississippi State University, the Blueway transforms neglected river access points into recreational areas, promoting environmental stewardship and cultural awareness (Ref 2).

The City of Gothenburg's policy for park and street trees was updated in 2016 and has the overarching aim to maintain and develop the ecological, historical, social and economic values of the city's trees and tree environments. Trees are described as having ecological, historical, cultural and economic values. They can provide ecosystem services such as habitat and biodiversity, air quality improvement, flood prevention, heat mitigation, recreation and aesthetic values [Ref. 1].

The policy applies to all trees in the streets, squares, and parks within the municipality but not to natural environments such as forests at the city's edge. Further, the policy is mostly relevant for municipality employees whenever they make decisions that will affect trees or tree-covered areas, such as zoning/planning and construction projects. Other actors in the city, such as private real estate or construction companies, are not required to follow the policy but are encouraged to consider it. The policy formulates sub-goals and guidances regarding the preservation of existing trees (prioritising large and old ones), the planting of new trees, the maintenance of trees, protection during construction work and finally, the taking down of trees, including compensation measures. The policy's direct effects is an expected improved management of trees within the municipal organisation. This may have further indirect benefits in the form of increased ecosystem service provision when the policy affects other projects [Ref. 1, 2].