Ecological restoration of existing green spaces

In 2022, the municipality of Cagliari launched a project to revitalize Viale Trieste, one of its avenues, by redesigning its roads and pedestrian areas and adding new green spaces. The project covers approximately 1,300 meters and 36,500 square meters, and will be completed in two phases, each focusing on different sections of the avenue. With a budget of 12 million euros, funded by municipal, national, and EU resources, the aim is to transform Viale Trieste into a vibrant, accessible, and attractive space for everyone.

The renewal will introduce new green spaces and improved drainage systems to enhance soil permeability. As part of this, some trees will be relocated to other areas of the city to address root issues and improve survival rates. Dead or unstable ficus trees will be removed, while 79 new trees will be planted. Older ficus trees will be relocated to city parks, with younger ones planted along the avenue to prevent pavement damage and promote sustainability. The project also includes upgrading water supply and drainage systems to manage stormwater more effectively, reducing the risk of flooding and improving sustainability. Public lighting will be modernized, with new street lamps and dedicated lighting for pedestrian and bicycle paths to make the area safer and more welcoming after dark.

However, the community has expressed concerns about the project, citing safety issues, delays, disruptions, and poor communication from officials. There is also significant opposition to replacing the historic ficus trees, valued for their environmental and historical significance, with Chinese pear trees and younger ficus (Refs. 1, 2, 3, 4, 5, 6, 11, 16).

Tempelhofer Feld stands as an innovative green solution in the heart of Berlin, addressing several issues of environmental justice, biodiversity, and urban resilience. Within the S-Bahn ring, only one in 20 residents lives in areas well-served by green spaces, and districts like Neukölln, Kreuzberg, and Tempelhof would face even greater scarcity without this vast expanse. Many residents in these neighborhoods lack access to private green spaces such as gardens or balconies. Without nearby parks, people are compelled to travel to other districts, exacerbating the congestion of green spaces and increasing local traffic.
Since its opening in 2010, Tempelhofer Feld has provided Berlin with over 300 hectares of open, green, leisure, and recreational space, making it one of the largest urban open spaces globally. Once the site of bustling air traffic, it is now a sanctuary for activities such as skating, strolling, gardening, picnicking, birdwatching, kiteboarding, and more. These wide-ranging uses showcase its transformation into an accessible, multifunctional green space that serves as a social equalizer, particularly for disadvantaged neighborhoods, a significance amplified during the Covid-19 pandemic.
The field is not just a recreational haven but also a vital ecological refuge. With over two-thirds of its area designated as green space, it hosts diverse ecosystems, including extensive natural meadows, lawns, and protected habitats for birds and other species. Certain areas are closed to the public to preserve these sensitive environments, emphasizing the balance between human activity and ecological conservation. Since 2019, animal landscape keepers, including around 100 resident sheep, have contributed to sustainable land management practices, promoting biodiversity and ecological health (Ref. 2).
Managed collaboratively by political, administrative, and societal actors, the site exemplifies integrated citizen participation in urban planning. (Ref. 3)

In 2017, many public parks in Iași were in poor condition, suffering from neglect and inadequate maintenance. Parks like Barboi were left unmanaged, with deteriorating infrastructure and overgrown vegetation. In response, the municipality of Iași initiated efforts to revitalize these green spaces.
The Barboi Park revitalization focused on rehabilitating 8,200 sqm of a degraded area (1 & 6, p. 106). Accessible pathways were repaired, and benches were installed to create a relaxing environment (1 & 4). Existing trees and vegetation were pruned, new trees and ornamental plants were introduced, and the soil was enhanced with more fertile layers to correct uneven levels (1 & 4). The primary aim of the new vegetation was to improve the park’s aesthetic appeal and boost biodiversity (1).
The project was led by the Municipality of Iași through its Public Services Department (Servicii Publice Iași), which oversaw the improvements (1 & 6, p. 106). It was part of a larger urban plan to expand and enhance the city’s green spaces (6, p. 106 & 7, p. 336). This plan aimed to improve the city’s visual appeal and increase livability for residents (6, p. 106). The project’s total cost was approximately €260,450.45 (6, p. 107). Later that year, the park was renamed "Woodrow Wilson" to commemorate the 100th anniversary of the U.S. mission to Iași during WWI, with a small monument erected to mark the occasion (5). The initiative also aligned with national guidelines on green space regeneration, per capita green space, and accessibility (7 & 9).

The Three Mile Creek Watershed project is part of the City Council watershed management plans (Ref 2) to stabilize the banks and the stream along the Twelve Mile Creek and Langan Park Lake, both of which drain into Three Mile Creek and Mobile Bay (Ref 1). The project aims to address the issues of degradation of the banks and destabilization of the creek, undercutting of sanitary sewer crossings and sedimentation in the creek and Langan Park Lake because of the increased water flow speed due to stormwater conveyance (Ref 2). Besides, major pollutants from run-off and sewage water contribute to the degradation of Three Mile Creek (Ref 5). Key initiatives include stabilizing the banks and streambed of the Twelve Mile Creek, dredging and restoring Langan Park Lake, and implementing instream structures to reduce erosion and protect infrastructure (Ref 2). The project also emphasizes reducing pollutants from stormwater runoff, improving water quality, and helping to protect the area’s estuarine and marine water resources (Ref 1). The project will increase natural habitat and contribute to regulating biodiversity by aiding in the abatement of invasive species such as the apple snail (Ref 2). It is expected to contribute to enhancing recreational access through the development of trails, educational programs, and water sports facilities. The overall goal is to restore ecological health, support flood control, improve the quality of life in the Mobile and Prichard communities and make the Three Mile Creek a recreational destination (Ref 6).

Named after the former Mexican president Lázaro Cárdenas, this green corridor project stretches over 4,5 km throughout one of the most densely populated areas in Belgrade. It was first built in the 1970s, connecting the building blocks 45, 44 and 70 of Novi Beograd, but has deteriorated since then (Ref. 4,9). Given the fact that close to 40.000 people live in the area which its highly vulnerable to climate change, action was taken to fully reconstruct the corridor for the benefit of local and surrounding residents (Ref. 3,4).
The project was implemented in three phases, according to the three blocks adjacent to the construction site starting in 2019. During the third implementation phase in 2022, however, major delays occurred due to disagreements with the local neighbourhood association "Common Action Block 70 and 70a", which demanded to be taken into consideration in the project's design (Ref. 2,5). Despite some cooperation between the responsible authority (Greenery Belgrade) and the association, demands could not be met (Ref. 5). In the end, the project was carried out as originally planned by the authorities, with a delay of approximately one year. Ultimately, the green corridor provides ample amenities for sports (bicycle lanes, basketball courts, playgrounds, etc.) and recreational activities (benches, chess area) as well as low-barrier infrastructure for all age groups (Ref. 9).
The project was initiated by President Aleksandar Vučić and supported by the current mayor of Belgrade, Šapić, who both have roots in the district (Ref. 4,6).

Salines Beach, a popular destination for over a million visitors annually (Ref 9), is facing severe erosion due to rising sea levels and poor coastal management. Since 1995, the beach has lost more than 20 meters in width. This loss has been worsened by vehicle traffic and the introduction of coconut trees in the 1950s, which reduced the native root systems that once helped to stabilize the coast (Ref 5). Now, the encroaching sea threatens to swallow the road that runs along the beach.
In response, the Salines Conservation Committee—comprised of concerned community members and environmental groups—has been advocating for urgent action to halt the erosion. They have called for a renaturalization of the area through the replanting of endemic species and restrictions on car traffic, both aimed at restoring the beach’s natural resilience.
When part of the road collapsed in July 2022, the committee took immediate action, organizing community-based interventions. These efforts included blocking traffic, raising public awareness, and planting over 60 endemic plants in the damaged area. The aim was to reestablish a root network capable of anchoring the coastline and capturing shifting sands (Ref 1; 2). The intervention was described as "a response to the urgent need to rebuild the root network, an ecological engineering solution recognized as the most effective method for retaining beach sand and slowing coastal erosion" (Ref 2; 1). The intervention on this section of the coast was first completed, then discarded by the municipality of Sainte-Anne (Ref 2). Regional and National agencies are currently undertaking the restoration works but it is unclear the stage of completion (See Ref 3).

The "Jardim do Eucaliptal" (Eucalyptus Garden) in Benfica is undergoing extensive renovations to improve its facilities and usability. Over time, the intensive urbanization of this neighbourhood has not left many traces of the historic eucalyptus forest typical of this area, but this urban park actively protects and maintains these old and heavy-trunk eucalyptus trees, growing amidst the park's more recent vegetation (Ref. 3). In the last few years, several trees have fallen, causing considerable damages to buildings and vehicles in the nearby area (July 2023), and leading to residents demanding financial compensations for damages and for the Lisbon City Council (CML) to take action for mitigating future problems (Ref. 5).
The renovation project implementation, expected to last six months, includes refurbishing the children's playground, sports field, toilets, and amphitheatre, along with introducing a dog park and outdoor exercise equipment (Ref 1). The park, originally part of the Quinta das Palmeiras de Guerreiro Galla forest, remains a crucial green space in the area despite extensive urbanization (Ref 2). These renovations, with a budget of 180,000 euros, also address the maintenance of public street furniture, the pavement, and lighting infrastructure, ensuring that the park meets the growing needs of the local community (Ref 3). These activities aim to meet the growing needs of the local population and improve these urban green spaces so that the community can enjoy them to the fullest. (Ref. 4).

The Mziuri Park in the center of Tbilisi and adjacent to the city's zoo was heavily impacted by floods and landslides that occured in June 2015 in Georgia. As a result, many of its facilities were destroyed, necessating the redevelopment of the site (Ref. 1,2). In 2017, the Georgian government initiated the Urban Reconstruction and Development (GURAD) Project with funding from the European Investment Bank (EIB) under the 100 million € framework loan. The park's reconstuction is one of multiple projects under the natural disaster recovery component of the GUARD Fund (Ref. 1,2). As of 2020, the park has been fully redeveloped catering to the needs of diverse groups, but especially youth and children with a number of different sports, cultural and recreational areas (Ref. 3,4). Importantly, construction was carried out under consideration of spatial adaptation measures for people with disabilities and with a renewed drainage system to mitigate the effects of future floods (Ref. 1). The park is now again one of the most important recreational areas in Tbilisi (Ref. 3).

In the city of Cagliari, in the location of Mount Urpinu, 6400 new trees have been planted. The project, initiated in 2022, sought to restore the area's biodiversity and to revitalize the park for the benefits of the citizens (Refs. 1, 3 & 8). In fact, in previous years, the park has been subject to various environmental and social hazards because of its conditions: the area has been subject to wildfires and abandoned wastes, and with time, it became a gathering point for drug addicts and homeless people, thus becoming unsafe for citizens and especially for children (Refs. 1 & 6).
Therefore, the Metropolitan City of Cagliari decided to reclaim the area and plant thousands of trees of various species (holm oaks, oaks, pine, carob and olive trees) over more than 6 hectares of land (Refs. 3 & 8). The project's goal is to restore biodiversity, mitigate temperatures, decrease air pollution, and increase citizens' sense of community (Ref. 1).