Improved air quality

The Liberties is one of the most recognizable urban areas in Dublin and Ireland, strongly associated with old Dublin, working-class communities, and the brewing and distilling industries. While rich in history, cultural significance, and local stories, The Liberties faces numerous placemaking and quality-of-life challenges. The area continues to experience significant dereliction, a fragmented urban fabric, and a shortage of high-quality green spaces. For instance, tree coverage in The Liberties is sparse, with good-quality street trees only found in a few small areas, such as Gray St. and Reginald St., along the South Quays, Cornmarket, and near the fountain on James St. The area has approximately 1,200 trees, amounting to less than 5% canopy coverage.
In response to these challenges, Dublin City Council enacted The Liberties Greening Strategy in 2015. Building on the Liberties' Local Area Plan, this strategy aims to develop a network of new urban parks, improve access to heritage green spaces, and refurbish existing parks and play areas. It addresses multiple goals, including ecological connectivity, water management, flood risk reduction, air quality improvement, social cohesion, environmental education, and public health. This strategy is an initiative of the Parks and Landscape Services Division of Dublin City Council, in collaboration with the South Central Area Office and with input from Áit Urbanism + Landscape and Mary Tubridy & Associates.
Since its implementation in 2015, the strategy has resulted in the development of two new community parks, enhancements to several green spaces, and the greening of public spaces. It has also introduced measures to support food production in community gardens and allotments, revitalize ecosystems, strengthen water management, improve air quality, boost carbon sequestration through tree planting, divert water from the local sewer network, prevent flooding, and regulate heat. (1, 2, 3)

The likely impacts of climate change in South Dublin County include an increased risk of flooding, more frequent summer droughts, deteriorating air and water quality, and biodiversity loss (1). To address these climate challenges, the county developed the County Development Plan 2016-2022 as part of the South Dublin Climate Action Plan, aiming to establish a comprehensive legislative and policy framework for green infrastructure (GI) planning (1).
The plan outlines various objectives, including creating a coherent, integrated, and adaptable GI network across South Dublin County. One key initiative is the establishment of native mini woodlands throughout the city, designed to form strategic links and integrate the GI Strategy’s objectives into all relevant land-use plans and development across the county (1).
The purpose of these mini woodlands is to connect green spaces across the city (minimum size of 100 sq m), sequester carbon, and promote biodiversity in suitable locations, such as built-up areas, low-grade parkland, and other zoned areas deemed appropriate (1). Given the long time required for tree growth, the project employs the Miyawaki method, planting a high density of diverse native species to create mature forests up to ten times faster than traditional plantations (2). These forests are estimated to host 20 to 100 times more biodiversity and absorb carbon up to 40 times more effectively, without the use of chemicals or fertilizers; key factors include ground preparation, planting density, and species diversity (2).
In 2022, the project held a planting day for the mini woodlands initiative on Mill Lane, where 1,200 native trees and shrubs were planted with the help of volunteers from local schools, the community, a corporate group, and the Mayor of South Dublin, Councillor Emma Murphy (2).

Over the past century, vast portions of the world’s oldest forests have been lost to clear-cutting and managed forestry (1). Arboretum Detroit is working to counter this trend by reforesting Detroit’s urban landscape, transforming abandoned city blocks into thriving groves of trees (1). Each parcel of land features trees that showcase the unique contours and characteristics of specific species, creating a diverse urban forest mosaic across the city (1). These "forest patches" are protected, designed to mature safely for generations, offering a space of tranquility and natural beauty for all Detroiters (1).
Arboretum Detroit’s main goal is to cultivate environmental consciousness, inspiring the community to consider our interconnectedness with nature and our impact on it (1). Through their reforestation mission, they demonstrate the ecological, cultural, aesthetic, and economic value of trees, both locally and globally (1). Trees alter our environment by using their leaves to filter the air we breathe by removing dust and other particles. Deciduous shade trees cool homes in the summer and allow the winter sun to heat homes when they lose their leaves. Trees can serve as a windbreak. The more compact the foliage on the group of trees the more effective the windbreak. Their pilot project, launched on Earth Day 2019, brought these values to life. Volunteers and members planted 21 trees across the site, including species like Princeton Sentry Ginkgo, Redpoint Red Maple, Paper Birch, Cedar, Yew, and understory trees like Kousa Dogwood and Forest Pansy Redbud, enhancing the habitat for local pollinators and birds (2). The trees were arranged in trios, interspersed with native seeds, soil, compost, and glacial boulders to create a healthy and engaging environment for all (2).

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)

Sri Lanka faces multiple natural hazards, including tropical storms, flash floods, and landslides. As the country's urban population has grown, development projects have encroached on wetlands, compromising their natural flood protection, air and water purification, and carbon storage capabilities. Additionally, hilly regions are at risk of landslides, particularly during the monsoon season, posing significant threats to vulnerable communities (4).
To address these challenges, the World Bank and the Sri Lankan government collaborated on the Metro Colombo Urban Development Project. This initiative focused on nature-based solutions (NBS) as cost-effective and sustainable approaches to risk management (4). By strengthening natural processes and ecosystem services, the project aimed to mitigate hazards such as floods, erosion, and landslides (4). Technical assessments by the World Bank highlighted the importance of wetlands in flood protection, leading to efforts to protect and restore 20 square kilometres of freshwater lakes, wetlands, and swamps (1, 4).
The project supported the Sri Lankan government in reducing flooding in the Colombo Water Basin and enhanced local authorities' capacity to manage infrastructure and services. It prioritised metropolitan investments to mitigate the physical and socioeconomic impacts of flooding and aimed to build long-term capacity for urban management and local service delivery (6).

In 2022 an afforestation initiative was implemented near a landfill located in the Tutora commune (1 - 6). Organized by the City Hall of Tutora, the event brought together representatives from the regional government of Iasi County, the "Asociația de Dezvoltare Intercomunitară pentru Salubritate" (ADIS), and volunteers from SC Girexim SA, SC Salubris Iasi, and Edil Industri Iasi. Together, they planted 2,000 acacia saplings, donated by the Forestry Directorate of Iasi (6). The afforestation action took place under the umbrella of the regional environmental campaign "Iasi Mai Verde" (Iasi More Green), led by the County Council of Iasi. This campaign promotes a range of eco-friendly activities, including educational programs in schools, waste cleanup events, and afforestation initiatives in partnership with ADIS, while actively encouraging the support and participation of local municipalities from across the region (1, 3, & 7).
"Iasi Mai Verde" aligns with national environmental strategies such as the Ministry of the Environment's "Curățăm România" (Let's Clean Romania) and the annual Planting Forest Month (3 & 6).
On the same day, as part of the Iasi Mai Verde initiative, students from a local school in Tutora were given a practical education workshop on how waste management operates at the regional level. The students were also invited to witness the afforestation action and participate, fostering a deeper understanding of environmental stewardship (1- 5).
The newly planted trees are acting as a natural barrier, and help improve air quality by filtering dust, pollution, and waste particles originating from the nearby Tutora landfill. In turn, this contributes to better living conditions for the residents in close proximity to the landfill, enhancing both their health and overall quality of life (5).

"Adopt a linden tree" is a project that involved the planting and adoption of linden trees in the city of Iași, spanning from 2019 to 2023 across three editions (1 to 8). The campaign was spearheaded by the National Athenaeum of Iași, in collaboration with the Mihai Eminescu Association from Vienna (2). This initiative was launched in celebration of the Athenaeum's 100th anniversary, and it specifically chose the linden tree because of its deep-rooted symbolism in the city of Iași. The tree is not only a natural landmark but also carries cultural and historical weight, as it is closely associated with Romania’s national poet, Mihai Eminescu, who is known for his love of linden trees.
In 2019, 100 linden trees were planted, a number that was repeated in 2020. In the 2023 edition, 50 trees were added, bringing the total number of trees planted through this project to 250 (1 & 4 & 5). An important and unique aspect of the initiative is the "adoption" of the trees by volunteers who participated in the campaign. These volunteers not only lent their names to the trees but also took on the responsibility for their care, ensuring the trees' survival and growth until they reached maturity .
Volunteers were encouraged to participate, and the campaign was supported by donations from individuals, businesses, and public institutions. The municipality of Iași also contributed by providing funds, approving the initiative, and preparing the land through its subsidiary, Servicii Publice Iași S.A., reflecting strong public-private collaboration.
Beyond its cultural significance, the campaign aimed to achieve several other objectives. These included enhancing the city’s aesthetics, promoting community engagement, and improving the quality of life in Iași by contributing to cleaner air and a healthier environment . The initiative also aimed to raise environmental awareness among residents and foster a stronger sense of responsibility toward the natural world. (1-8)

The old Altadis tobacco factory in the Los Remedios neighbourhood of Seville is being transformed into an area with offices, hotels and lots of green space. New green space will connect existing green areas next to the river, resulting in a total of 13 378 m2 of green areas within 3 ha of public space. The park will increase the number of trees in the area by 60 per cent, creating a lot more shaded areas, which are needed during the hot summers [Ref. 1-5]. Additionally, the trees will contribute to carbon sequestration, improve air quality and promote biodiversity [Ref. 5]. The park is meant to become a popular destination for recreation, new entrances and a bridge over the river will connect the surrounding neighbourhoods to the park [Ref. 1-3]. There will be areas for physical activity, dog walking and play for children [Ref. 1, 4]. The project is being carried out by real estate company KKH Property Investment, which owns the land and will invest 250 million EUR in the project as a whole, of which 5 million EUR is designated for green spaces. KKH has made an agreement with the City of Seville to ensure the project has benefits for the area and its citizens, and follows previous plans for the area, which have involved citizen participation [Ref. 3, 6, 9].

On a small roadside green space in Berlin, a tiny forest was created. The idea of Tiny Forests comes from Japan, there are already some in France and the Netherlands, and since 2020 also in Germany. Tiny forests are constituted of trees planted densely next to each other in small spaces, such as tiny green roadsides.
At Oderstraße, the NGO TinyForestBerlin planted an even smaller forest, a nano forest on a roadside where trees cool down the area, filter the air and create a habitat for insects. Trees in urban areas loosen up the dense and degraded soil, allowing it to store carbon and let rainwater properly seep into the ground to prevent urban flooding. Roadsides are hardly utilised or recognized in their environmental potential, such as hosting a nano forest. Projects like the one implemented by TinyForestBerlin present an approach for collaboration between the district and civil society, as the district's park department lack the capacity to maintain small roadsides. The project at Oderstraße is the first official tiny forest in Berlin, as a previous planting campaign in Friedrichshain was not entirely legal due to missing approval of local authorities. (Ref. 2; Ref. 5)
The TinyForestBerlin association has set itself the goal of creating such small nano-forests all over Berlin. An ambitious project that aims to enrich the city's green spaces and contribute to improving the urban climate. The trees planted on Oderstraße are one of many smaller planting projects that are spread throughout the city on public as well as private land. (Ref. 3)

"Urban Natural Area Ciric" is an initiative aimed at designating the forest and lakes of the Ciric area, located on the outskirts of the city of Iași, as an Urban Natural Area. To achieve this goal, the initiating organizations—NGO Civica and the Ornithological Association of Iași (SOR)—have developed a comprehensive report focused on the Ciric natural area, which monitors species and habitats while identifying pressure points on biodiversity and necessary conservation actions, as well as the benefits these areas provide.
In the Ciric area, various flora and fauna species have been identified, with some holding high protection status (14 bird species) or being of community importance and conservation interest. However, this ecological richness faces threats, as factors such as rapid urbanization, water pollution, and waste disposal have been identified as significant risks to the ecosystems.
In response to these challenges, the NGO aims to collaborate with the municipality to create protective municipal laws that will not only recognize the area as an Urban Natural Area but also ensure its inclusion in development plans. This partnership seeks to establish regulatory measures and strategies that will safeguard and enhance the biodiversity and ecosystems of Ciric. Additionally, the organizations have highlighted the social and physical benefits of the area for residents, including flood regulation and prevention, pest control, provision of clean air, and recreational and scientific opportunities.
To further raise support and awareness for their efforts, SOR and Civica conduct guided tours, educational workshops, and photographic exhibitions. They have also set up two informational panels in the area that highlight the biodiversity of Ciric. Furthermore, the two NGOs have partnered with regional organizations to create the "Rețeaua națională de arii naturale urbane" (The National Network of Urban Natural Areas) and have received funding from the EEA Grants. (1-8)