Green densification model

The pilot project in Bairro Padre Cruz, Carnide, Lisbon, is a groundbreaking initiative aimed at enhancing women's safety in public spaces and improving access to public transport. Launched in June 2024, this project stems from extensive consultations with local women to address their specific security concerns (Ref1). It involves strategic interventions like better lighting and the relocation of bus stops to safer areas, ensuring a more secure environment for women (Ref4). A key element of the project is the greening of the area through tree planting and the creation of more harmonised public spaces, contributing to a more pleasant and welcoming neighbourhood (Ref2). Funded by the Recovery and Resilience Plan (RRP), this initiative aims to foster greater inclusivity and safety in urban design, with completion expected by 2025 (Ref4).

The "Jubilee Park" (Jubileumsparken) is a city park in the developing area of Frihamnen in central Gothenburg. The first part of the park finished construction in 2024, but the aim is that the park will continue to grow and develop until the year 2035 [Ref. 1-2, 5]. The park is said to be the result of the wishes of the people of Gothenburg to have better access to green areas and water before the city's 400-year jubilee in 2023 [Ref. 2]. To achieve this, the park has been constructed gradually in cooperation with residents, using a method called placemaking, where activities and amenities are tested in place to get feedback from residents before being made permanent [Ref. 2, 4]. Additionally, activities in the park are being run by a youth organisations, which also offers summer jobs to young people from across the city and aims to engage marginalised groups [Ref. 1, 6]. The park provides amenities a sculpture-based playground, an outdoor classroom, places to sit and a harbour bath at the edge of the park, with outdoor pools and a sauna. The park contains elements for biodiversity such as trees, meadows and an area for urban farming, increasing biodiversity and connectivity compared to the previous land use as a harbour [Ref. 1, 2, 9].

The Juan Angola River is an urban channel included in the system of rivers and channels of Cartagena, and it connects the Ciénaga de la Virgen wetland and the Bay of Cartagena, facing similar issues as the Cienaga de la Virgen such as illegal occupation of its shores, illegal waste dumping, deforestation of mangroves, and pollution. The recovery plan for the Juan Angola River is led by the EPA Cartagena (Environmental Protection Agency), with the support of other institutions, aiming to restore the Juan Angola’s ecosystem. This includes targeting the mangrove forest, dredging the natural channel, and delineating buffer zones with urban infrastructure to create public recreational spaces. The activities involve relocating people illegalling cupping informal settlements from the river shore, moving an existing bridge (the Benjamín Herrera bridge) which obstructs the current, recovering the low tide and riverbed areas, building pedestrian paths, clean the riverbank, recover mangrove areas and establish programs of education and environmental awareness (ref 1 and 2).

As an industrial city under climate change, Birmingham has been confronted with multiple environmental risks such as air pollution, fluctuating precipitation and flooding (Ref 3). The Big City Plan is a 20-year city center regeneration plan to support Birmingham’s sustainable transformation, where the delivery of the Eastside City Park was prioritized (Ref 1, 2). Completed and opened to public in 2013, this first new park in Birmingham for 130 years is a linear site which connects the city center along the frontage of Millennium Point eastwards towards the Digbeth canal. (Ref 1, 4, 5). Providing 2.73 ha of urban green spaces, the multi-award winning development features more than 300 trees, a 110 meter canal water feature and a public square with 21 jet fountains, and offers “a moment of green in a journey through the city” (Ref 1, 6).

The project features a vertical garden, or "living wall," on the facade of a residential building in Berlin’s Kreuzberg district. Constructed in 2016, the building replaced a WWII-damaged plot situated between two existing structures. With a strong emphasis on sustainability, the project minimizes its ecological footprint in various ways. The 660-square-meter plot retained original elements of the location’s history: the two surviving sections along Glogauer and Reichenberger Strasse were restored after the war, while the rubble from the destroyed corner was used to fill in the basement. This approach allowed the new construction to be built over the original foundations, preserving historical integrity while reducing construction costs and material use.
At the core of the building’s design is a green agenda, embodied in the vertical garden that helps absorb noise and pollution from the bustling street below, improving air quality for residents and passersby. The selection of winter-hardy plants ensures that the facade remains green year-round, while also cooling the surrounding area and mitigating the urban heat effect, which is especially valuable in densely populated neighborhoods. The greenery contributes to the local microclimate, providing both environmental and aesthetic benefits.
For residents, the garden is made accessible through rectangular box balconies that project from the green wall, allowing them to engage closely with the plants and enjoy the immersive garden atmosphere. The plants grow on a support structure that is securely anchored in the brickwork, receiving water and nutrients through an integrated, precision-controlled irrigation and fertilization system. Maintenance of the plants occurs twice a year, with new additions planted each spring to maintain the garden’s health and visual appeal.
The building itself, privately owned, contains a mix of holiday rentals and residential apartments. Architect Sarah Revière designed the project. (1-6)

The Cinturón Verde de Independencia initiative is a pilot intervention that seeks to plant an urban forest in the lower middle-class district of Independencia (1) in the northern part of the urban territory (3). Here, 19% of the population lives in high-risk conditions, settled on steep slopes, and threatened by landslides (3).
It is part of a broader planning strategy that involves proposals engaging different levels of government (4). This project seeks to afforest the district's hillsides to improve the environment, reduce air pollution, improve the quality of life of its inhabitants, manage waste, regulate shade, control erosion, increase wild biodiversity, and provide spaces for environmental education (2). The Independence Green Belt is linked to a wide range of plans, projects, and decrees that have been developed by actors at different levels of government since 2016 (4). It works hand in hand with the EBA Lomas programme and seeks to create a green belt along the Lomas-city interface, which acts as a buffer zone for this sensitive ecosystem and creates a protective boundary against the expansion of irregular human settlements while providing a space for environmental awareness (2).
This program was developed by a consortium of multiple private, public, national, and international parties with strong community support (3). In two phases, an urban forest park of 4,800 of native trees irrigated with treated wastewater has been planted. During the first phase, PREDES planted 3,300 trees with USAID support in 2015, and another 1,500 were recently planted by PERIFERIA (consultants) (3).
The Independencia Green Belt occupies the hill areas of the district of the same name and relates to a possible metropolitan-scale buffer belt.
Its boundaries take advantage of the seven Sustainable Ecotourism Forest Parks (PFES) in the District Municipality of Independencia (MDI), as well as 115 hectares of the Amancaes Lomas (4). It aims to conserve 400 hectares (4).

The Bahlui Forest project consists of a tree-planting initiative along the banks of the Bahlui River, which flows over a distance of 11 km through Iasi, practically dividing the city in two (1, 2, 6). The project aims to reduce the high levels of air pollution prevalent in the city, increase green spaces along the river and in the urban area, and enhance the aesthetic appeal of the surroundings, thereby improving the quality of life for local residents (1–3, 8, p. 188). The initiative was planned by the Municipality of Iași in collaboration with the Prut-Bârlad Water Basin Administration, the regional authority responsible for the river’s proper management (1–6). Furthermore, the "Ion Ionescu de la Brad" University of Agricultural Sciences and Veterinary Medicine in Iași provided the technical expertise needed to select and plant appropriate species (1–3, 7).
The planting completed in 2024, covers the river section between the Sf. Ioan bridge and the Stone Bridge (3–5). In total, 1,200 native species were planted, including four tree species—Willow, Malin, Red Maple, and Birch—and three shrub species (3–6).
This initiative is part of a broader municipal strategy to revitalize the riverbanks and address key issues (8, 9). Due to its natural geomorphology, the river represents a barrier in terms of accesibility between different parts of the city, and infrastructure and improvements need to be carried out to manage this problem (8 & 9). Therefore the areas around the river are sought to be revitalised to fullfil its touristic and recreational potential, ultimately becoming a green corridor and representing a new axis of development for Iasi (8, p. 344). Improving its green surfaces would also support efforts to increase green space sq.m. per inhabitant in the city, which falls short of the national requirement of 26 sq.m. per inhabitant (8, p. 189).

Del Nervi Park is a project co-led by the Port System Authority of the Sardinian Sea and the Municipality of Cagliari. Completed in 2021, it transformed a long-abandoned and degraded area on the Cagliari waterfront into a vibrant green space. The two-hectare site surrounds a 1950s industrial building and underwent extensive redevelopment to enhance its structural integrity and convert it into a public park. With a budget exceeding 5 million euros, the project prioritized green investments by creating new pedestrian and cycling paths, along with green spaces featuring local plants, flower beds, grass, and lawns.

Nervi Park is set to become a key destination for leisure, sports, and cultural activities, while also providing the Cagliari community with greater access to green spaces. The environmental and urban renewal efforts aimed to beautify and modernize the area, with future development plans focusing on long-term management and the introduction of commercial activities to further enhance the space
The project faced significant barriers, including prolonged disruptions due to the COVID-19 pandemic, which halted work for about eight months. (Refs. 1, 2, 3 & 4).

The Three Mile Creek Greenway Trail project aims to transform the existing creek into a valuable community asset by developing a multi-use greenway trail (Ref 1). This greenway will connect various parts of the city through walking and biking paths, linking neighbourhoods, parks, and commercial districts while providing access to unique natural areas (Ref 2). The creek having been adandonned for decades (Ref 5), the initiative seeks to turn 3 Mile Creek (3MC) into a vibrant natural corridor that fosters recreation, education, and economic activities (Ref 1, Ref 2). The project aims also at reducing pollutants in the waterway, restoring natural stream channels, and maintaining flood protection (Ref 1).
The 3MC Greenway Trail is expected to become a key feature of Mobile's urban landscape, offering numerous benefits. These include enhancing community health, both mental and physical (Ref 2), and stimulating the local economy by increasing property values, tax revenues, and opportunities for recreation-related businesses and job development (Ref 2). Additionally, the trail will improve community connectivity by linking neighbourhoods, parks, and schools, thereby fostering a stronger sense of community and better access to public spaces (Ref 2). Lastly, the project will contribute to environmental restoration through stormwater management, pollution reduction, and natural habitat preservation (Ref 2).
The greenway is part of a plan to restore the health of the Three Mile Creek watershed and is the first major piece of a long-term Mobile Greenway Initiative (MGI) (Ref 4).

The Bosque Vertical do Centro Cultural de Belém (CCB) in Lisbon (Vertical Forest at CCB), designed by Francisco Caldeira Cabral, is an innovative vertical garden inaugurated in 2020. Spanning two 17-meter-high walls with 7,524 plant pots, it enhances urban biodiversity by attracting birds and insects (Ref 3). This project offers recreational and aesthetic benefits, making the entrance of the cultural centre into a green space (Ref 4).
The garden helps reduce air pollution by absorbing pollutants and producing oxygen. It uses a drop-by-drop irrigation system made from recycled PVC, ensuring efficient water usage and retention (Ref 1). Furthermore, the garden improves air quality, aims to mitigate urban heat island effects, and conserves water (Ref 2, Ref 5).