Increased number of species present

The Vale da Ameixoeira Urban Park is a key part of Lisbon's Peripheral Green Corridor, covering 20 hectares and aiming to enhance the city's ecological and social resilience. It includes pedestrian and cycling paths, rest areas, picnic spots, skate parks, and playgrounds, enabling recreational activities while providing scenic views (Ref 1). The park has undergone several requalification initiatives, including the tree planting project in 2018, which saw the community and municipal bodies plant over 130 native trees and shrubs, promoting biodiversity and environmental sustainability (Ref 3). Additionally, the park supports community-based vegetable gardens, integrating horticultural practices to promote local engagement and foster social inclusion (Ref 3). More recently, as part of the Life Lungs project, another 600 drought-resistant trees were planted to mitigate climate change impacts, such as urban heating and water scarcity (Ref 5). The Lisbon Participatory Budget funds the project and reflects the community’s demand for sustainable urban development (Ref 2).

The intervention in the Sant'Elia neighborhood, which opened in 2018, created a new green area of approximately 2,600 square meters designed to enhance the urban environment and improve the quality of life for residents. This space includes an olive grove and an orchard, featuring pathways and landscaping that integrate local plant species.
Along the side facing Via Utzeri, olive trees and a small grassy area have been planted, complemented by stabilized gravel paths for walking. The orchard contains 28 fruit trees, including citrus, pomegranate, quince, and fig trees, along with Mediterranean shrubs, allowing residents to freely enjoy the fruits for their own consumption.
The entire area is equipped with an automated drip irrigation system, while the grassy sections utilize sub-irrigation. Additionally, a central roundabout in Piazza Giovanni da Verrazzano has been adorned with a lawn, palms, and vibrant rose beds.
Commemorative plaques honor tenor Piero Schiavazzi and local resident Samuele Utzeri, who tragically passed away in Kosovo. The area also features signs encouraging respectful harvesting of fruits and permits dogs, provided they are kept on a leash (Refs. 1, 2, 3, 4 & 5).

The Tirana Vertical Forest is part of the city's 2030 Master Plan and aims to enhance urban biodiversity and create green spaces through innovative urban design (Ref. 1,2). The project was developed by Stefano Boeri Architetti, the same studio that has designed similar, well-known structures in cities like Milan, Utrecht and Nanjing (Ref. 6). The completion of the 21-floor building is expected in late 2024 and will feature 105 apartments and a commercial ground floor as well as 145 trees and over 3,200 shrubs and bushes which are integrated into the balconies and façade of the project (Ref. 1,2,3). Various Mediterranean plants have been incorporated, including colourful, scented and aromatic types, which harmonize with the local ecosystem. To maximise the space available for green features, a dynamic structure with alternating balconies and full-height windows has been built (Ref. 1,2). Ultimately, the project anticipates improving air quality, reducing noise, and providing insulation. The greenery is expected to capture fine particulate matter and up to 8 tones of Co2 per year while also creating a healthier microclimate for those inside the building (Ref. 1,6).

The "Tree Plantation Month" is an annual national initiative in Romania, organized by the Ministry of Environment, Water, and Forests through the National Directorate of Forests. This initiative focuses on afforestation, forest regeneration, and raising awareness about the ecological benefits of forests, while promoting sustainable behaviors (4, 9, 10). Having been in place for 60 years, the program has recently aligned with the principles outlined in the 1991 Paris Declaration on the Sustainable Development of Forests (10). At the national level, the initiative is regulated with overarching goals aimed at protecting and sustainably managing Romania's forests (9). The program allows for the involvement of various actors, including public institutions, municipalities, NGOs, and schools, who collaborate with regional forestry directorates to implement local activities (4).
In 2019, as part of this initiative in Iași, the Asociația Tineretul Ortodox Român Iași (ATOR), a youth-led religious association, actively participated in one of the campaigns . They planted 1,000 tree saplings in the Moara de Vânt district, an area that had suffered from deforestation and was prone to landslides (1, 2). The afforestation efforts were designed to address these environmental challenges by stabilizing the soil, reducing the risk of overflow and flooding, maintaining soil moisture, and regulating extreme temperatures (1). To ensure long-term success, the saplings were regularly monitored, and restoration efforts were carried out in cases where the trees were affected by fires or drought (3).

The Hellenic Park by Farka Lake stands as a symbol of the growing relationship between Albania and Greece (Ref. 1,2,3). The project was designed and implemented by the Municipality of Tirana in partnership with the Greek Embassy and supported by Greek companies operating in Albania. Its inaugurated was attended by the mayors of both capitals and the Greek Ambassador to Albania (Ref. 3,4). The opening ceremony marked three significant milestones: the 200th anniversary of the Greek Revolution, the 50th anniversary of the restoration of diplomatic relations between Greece and Albania, and the 40th anniversary of Greece's membership in the European Union (Ref. 4). The park reflects bilateral unity through emblematic vegetation, such as olive trees, which hold cultural significance in both countries. Beyond enhancing diplomatic ties, Hellenic Park fosters inclusive sports and cultural activities and provides a space for recreation (Ref. 1,3,4).

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 South Hennepin Marsh habitat restoration project, located below the Grosse Ile Toll Bridge causeway, within the Detroit River's Trenton Channel near Grosse Ile, Michigan, aims to restore and protect one of the region's most critical wetland habitats. This emergent marsh, historically vital for fish and wildlife, has suffered significant degradation due to river currents, boat traffic, and winter ice flows. The project, identified as a priority in the 2002 Habitat Protection and Remediation report for the Detroit River, encompasses the restoration of over 1,000 linear feet of protective shoals and 20 acres of productive wetlands, home to various native plant species such as rushes and submergent macrophytes.

The primary goal of the project is to stabilize and enhance the marsh's habitat, improving conditions for fish, waterfowl, reptiles, amphibians, and other wildlife. Restoration activities include the placement of approximately 10,000 cubic yards of rock and soil to rebuild eroded shoals, installation of erosion matting, and re-establishment of native vegetation. Additional habitat features, including habitat logs, mudpuppy structures, and stone spawning beds, will provide crucial breeding and feeding areas for species such as walleye, northern pike, and lake whitefish.

The project also incorporates soft engineering solutions, such as fallen branched trees and strategically placed stones, to support pollinators, birds, and reptiles. Feasibility studies and design plans were completed by Environmental Consulting and Technology, with funding from NOAA, and construction was carried out by E.C. Korneffel Company beginning in 2021. The project reached completion in November 2022, successfully restoring the shoals and protecting the marsh from further degradation. These efforts have significantly enhanced habitat availability, ensuring the sustainability of the South Hennepin Marsh as a critical ecological site within the Detroit River system.
(Ref.1-4)

The project to revitalize the Huveaune River and its biodiversity is taking place in Aubagne, a city within the Marseille Metropolitan area. For a long time, the river received little attention, constrained by urbanization, and was even covered for several hundred meters. Urbanization and the construction of a road have made the floodplain more susceptible to flooding (Ref 2). The initiative aims not only to restore the Huveaune and its environment but also to strengthen the connection between residents and the river (Ref 1) while reducing flood risk as a critical objective (Ref 1).
The challenge is transforming the area into a higher-quality environmental space with resilient ecosystems. A diagnostic conducted during the project's design phase revealed the site's degraded state, including the presence of invasive species, steep banks unsuitable for riparian vegetation, poor waterway conservation, and disrupted ecological continuity (Ref 2).
Key actions include revitalizing the river and its biodiversity, removing artificial banks, and creating new meanders to give the river a more natural shape. Diversifying flow patterns will create habitats for aquatic and fish species by varying water heights and flow speeds. This involves increasing the river's sinuosity and varying the width of the minor riverbed (Ref 2). Additional steps include planting trees and shrubs adapted to the Mediterranean climate with low water needs (Ref 2). To bring residents closer to the river, plans include creating walking and cycling routes, sports equipment, educational panels, and useful visitor facilities such as benches, water points, and restrooms (Ref 3).

The redesign of Reinprechtsdorfer Street in Vienna is a greening initiative aimed at climate adaptation by reducing local temperatures and increasing green space in a densely built urban area. Implemented within one year, the project included planting trees, adding green beds, and widening the pavement to create a more inviting environment. New seating areas, drinking stations, and water play installations were introduced, providing spaces for relaxation, cooling off during high temperatures, and fostering social interaction. Accessibility and traffic safety were enhanced by leveling the pavement with the street and adopting a one-way system for cars.
The project, realized in 2023, was part of Vienna's city-wide "Out of the Tarmac" initiative and was spearheaded by the district and city council. It originated from discussions and a participatory design process with citizens dating back to 2014. Previously, Reinprechtsdorfer Street served as a congested connection between Wienzeile and Gürtel. The plan seeks to transform it into a “climate-friendly shopping street.”
The redesign involves planting 32 new trees accompanied by flower beds, plus three standalone flower beds. Sidewalks were widened, and amenities included parking for 36 bicycles, nine benches, and seating for 46 individuals. Cooling features such as two water installations, three mist columns, and two drinking hydrants will enhance comfort.
Renovation began in spring 2023, focusing first on the 400-meter stretch between Schönbrunner Straße and Arbeitergasse. A structurally separate one-way cycle path will link Schönbrunner Straße to Bräuhausgasse, while the existing cycle lane against the one-way system remained unchanged. (Ref. 1, 2, 6)

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].