Maintenance and management of urban nature

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

Välen is a natural area 8 km south of central Gothenburg, established as a protected nature reserve in 2013. Prior to the establishment of the nature reserve, Välen was an agricultural area that experienced environmental degradation due to pollution from a nearby sewage treatment plant. Västra Frölunda Nature Conservation Association leased the land in 1985 in order to allow cattle to graze through the overgrown meadows as a form of landscaping approach [Ref. 5].
The City of Gothenburg took the initiative to protect and manage the area as a protected reserve [Ref. 1, 2]. It is formed of wet meadows and deciduous forests and has a total area of about 68 hectares, of which 52 ha are land and 16 ha are water. Välen is situated by the sea and the mouth of a small river, and protects some of the coastal waters. Residential areas surround the nature reserve and are a popular destination for recreation [Ref. 1-3]. In creating the nature reserve, efforts were made to make the area more accessible to visit and to provide learning opportunities. New paths, entrances and signs were established [Ref. 3-4]. The nature reserve is described as contributing to several national environmental goals, particularly goals related to biodiversity [Ref. 2].

Corkagh Park, spanning 120 hectares, holds significant historical and cultural value for the local community of Clondalkin. The park offers an extensive range of facilities, including football pitches, a newly redeveloped playground, baseball pitches, cricket amenities, and a purpose-built road cycling track. Over the past two years, Corkagh Park has experienced a notable increase in footfall and usage as visitors are drawn to its expansive open spaces. With its rich vegetation, open wetlands, and rolling hills, Corkagh Park provides a unique environment that caters to both wildlife and human visitors. Since its establishment as a public park in 1986, the park’s vast open spaces have served the local community and attracted visitors from the broader region. Currently, Corkagh Park is surrounded by the Village of Clondalkin and nearby residential developments.
Currently the park goes through a redevelopment process that involves redesign of several areas including introduction of native vegetation. The enhancement of the park is led by the South Dublin County Council and will feature a central hub area at the heart of the park. This hub will feature a coffee shop, an event space, additional seating, and new play areas. Enhancements to the Fairy Woodland Trail will include additional play elements and seating, as well as a new pedestrian pathway linking the lakes, while maintaining and safeguarding the existing mature trees. The project also includes the felling of ash trees affected by Ash Dieback, with these trees being replaced by native specimens to sustain the park’s ecological integrity. Native edge planting buffers will be established to reduce noise from the N7 and promote local biodiversity. Additionally, the project will address the existing car parks by implementing necessary improvements to better accommodate the park’s visitors. (4, 6)

The reforestation project at Bela Vista Park in Lisbon is a collaborative effort by the MEO Kalorama music festival, the Lisbon City Council, and Quercus (local NGO). The intervention began with a community planting event in February 2024 with the planting of 80 native trees, and the goal to plant a total of a total of 1,000 trees. The project aimed to improve the park's biodiversity, enhance carbon absorption, and support local wildlife. The tree species were chosen for their suitability to the local climate and their ability to integrate with existing vegetation. Local schoolchildren and residents participated in the planting, serving as a community engagement activity. This initiative is part of broader efforts to make Lisbon greener and to positively contribute to the local environment, given the disturbance caused by the MEO Kalorama festival (Ref 1, 2, 3).

The Çukurova University Botanical Garden was initiated in 1972 by the Department for Landscape Architecture to protect and conserve the rich native and non-native biodiversity of the region for future generations (Ref. 5,9). Its establishment responds to the lack of Botanical Gardens in Türkiye despite the country's great diversity. The Garden also wants to offer protection for increasingly threatened species in the face of rapid and uncontrolled urbanization (Ref. 5,9). Being located close to two Deltas and an important agricultural region, the collection also aims to include a great number of wetland and agricultural species, drawing public attention to the importance of these ecosystems (Ref. 6). As such, the University invites every school in Adana to visit and participate in its ongoing educational activities and primary school children are offered hands-on gardening programmes (Ref. 1,2). Furthermore, visitors can immerse themselves and learn about various vegetation zones, including endemic maquis, where stairs, walking paths and information boards have been installed (Ref. 4). The University maintains research activities in the Botanical Garden and in on site laboratories, which regularly host interns (Ref. 4). To ensure the stready supply of plant material for landscaping and education, nurseries have been set up and in 2020 a 250 m² medicinal and aromatic plant greenhouse was added where students of the Faculty of Agriculture are trained and endemic species grown (Ref. 9,10).

A small biodiversity park was established in Härlanda Park, an old prison complex which today houses a culture centre, a pre-school and office space. The area was previously used as a small lily garden, but this project implements more biodiversity-promoting features such as a bee hive, varied flowers and trees, different types of soil and insect hotels. The municipal real estate company Higab owns the park and partnered with Stadskupan, which works with urban beekeeping, biodiversity, and rewilding, to design and create the park. They also involved Vägen ut! (translates to "the way out"), a social enterprise that employs people who are far from the labour market due to substance abuse issues to help maintain the park in a socially inclusive way. The park has pedagogic features and events for local businesses and organisations as well as the public. The beehive was established in 2022, while the entire biodiversity park was established in 2023. The project will go on for three years and be evaluated yearly. [Ref. 1, 2, 3].

The Phoenix Park initiative was carried out by the "Gheorghe Asachi" Technical University of Iași in partnership with the Iași Communitarian Foundation, the BorgWagner Fund, and the Municipality of Iași. It involved the rehabilitation of a green space within the university campus. Covering an area of 3,000 square meters, the renovation was based on the winning design from a student competition focused on improving campus spaces.
The park was designed to include facilities for physical exercise (calisthenics equipment), recreation (badminton court and ping-pong table), and social interaction spaces. It also serves as a buffer to reduce noise from the surrounding areas.
The total cost of the project amounted to 121,200 euros, with the university covering infrastructure expenses, the municipality providing the labor for rehabilitation, and the private fund contributing 15,150 euros. The implementation of the design was overseen by the student designer and coordinated by the NGO and the university’s Association of Student Architects.
This initiative is part of a larger urban regeneration project by the university, in collaboration with the municipality and the Communitarian Foundation, where several campus green spaces are being rehabilitated based on student designs. The overarching goal is to enhance students' quality of life and promote healthy lifestyles through the creation of green spaces during their time at the university. (1, 2, 5, 6, 8, 13, p. 92)

Phoenix is one of the hottest cities in the United States, with temperatures regularly exceeding 40°C (104°F) for more than 90 days each year. The urban heat island effect is severe here, posing a significant health risk. Many communities in Phoenix lack equal access to shade cover—often, the impact of extreme heat disproportionately affects low-income neighborhoods that lack resources for tree planting and maintenance. In contrast, wealthier areas tend to have more trees and are visibly greener, which helps reduce the heat residents experience.
To address these disparities, the City of Phoenix partnered with SRP, a not-for-profit public power utility, to launch the "Right Tree, Right Place" program in 2018. This initiative aims to bring shade relief to areas most in need, such as parks, public transit stops, and schools, while replacing older trees that interfere with SRP power lines. SRP and the city work together to identify trees that pose risks to overhead power lines, and for each tree removed, three new trees are planted—either in a different location or with a species better suited to coexist with power lines.
One of the program’s notable projects took place in West Phoenix’s Cortez Park, where 24 drought-tolerant trees from four different species were planted. This diversity helps protect the trees against pests and other natural threats, ensuring their longevity and resilience. Through initiatives like these, the "Right Tree, Right Place" program contributes to Phoenix’s larger goal of developing a robust, biodiverse urban forest. By expanding green infrastructure, the city aims to reduce local temperatures, improve air quality, and create cooler, healthier neighborhoods for all residents. (1-8)

Parque Lácides Segovia is an urban park located on Isla de Manga in Cartagena, Colombia. The park was inaugurated and revitalizated in June 2014 to serve as a multifunctional green space promoting cultural, social, and environmental activities. Named after General Lácides Segovia, a notable figure in Cartagena's history, the park aimed to provide a family-friendly and culturally enriching environment (ref 1). The primary goal was to transform a neglected urban area into a dynamic public space that fosters community interaction and enhances local culture. The park aimed to create a safe, inclusive, and accessible environment for residents of all ages, promoting social integration and cultural activities. Additionally, the project sought to establish a green area contributing to the ecological health of the city through urban greenery (ref 1, 2).
The first revitalization in 2014 involved facilities, planting native trees, and setting up public amenities such as Wi-Fi, seating, and cultural spaces(1, 2, 3).
This new revitalization in 2024, led by the local government of Cartagena, will focus on enhancing the infrastructure of both the park and the surrounding sports area in Manga to improve sustainability. The project has an estimated budget of approximately USD 675,000. The improvement works to provide better facilities and infrastructure to support recreational and sports activities, benefiting the community and promoting a healthier urban environment (ref 6). The park is essential for the community; it was recently the subject of several citizen science projects led by the Montessori School, including research identifying the park's ecosystem services (ref 3).

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).