Increased number of species present

The Kikås dump is a landfill in Mölndal, south of Gothenburg, where an area has been permanently covered with a sealing layer and inert material. This project aimed to utilise the area to increase biodiversity by establishing flowering meadows and an insect hotel, creating a habitat for wild bees, butterflies and birds [Ref. 1-3]. The City of Mölndal initated the project and sowed meadow flowers, established sand beds for burrowing insects, an uneven, rocky terrain and a large insect hotel [Ref. 1, 3]. The area is also meant to be a destination for recreation and learning about biodiversity. The Insect Hotel is marketed as the largest in Sweden, and it includes information signs and an outdoor classroom. The project is meant to raise awareness about biodiversity and ecosystem services such as pollination [Ref. 1, 4-6]. The area borders natural areas such as forests and wetlands and is meant to have positive ecological effects in the border zones. The project will contribute to the environmental goals of the city, in particular, "a rich plant and animal life" [Ref. 3]

MINI Ireland, in collaboration with conservation charity Earthwatch Europe, has launched Ireland's first "Tiny Forest" at the Tolka River Project, a community-driven rehabilitation program in Co. Dublin. In a space the size of a tennis court (195m²), nearly 600 native trees have been planted, creating a densely packed, environmentally efficient green area.
This partnership with Earthwatch aims to raise awareness for local environmental projects and foster community bonds. Green spaces like this offer valuable areas for people to connect with nature, exercise, unwind, and reduce stress—one reason the Tolka River Project center was chosen as an ideal location. "Tiny Forests" are remarkable for their impressive efficiency within a small footprint: by planting 600 native trees closely together, the forest grows naturally with increased density, achieving up to 30% more plant density, ten times faster growth, and up to thirty times better carbon dioxide absorption. Over the next three years, this forest is expected to attract more than 500 animal and plant species, transforming into an accessible mini-ecosystem.
The project uses a variety of locally sourced native trees, including silver birch, alder, hazel, hawthorn, and gorse, which together will form the natural layers of a forest. Ireland's first Tiny Forest was planted on March 22, 2023, at the Tolka River Project site in Dublin's Buzzardstown area. The Tiny Forest, located near the center, will serve as a space for reflection and recovery, supporting clients on their journey to rehabilitation. The planting event was a day of celebration, with Tolka River Project clients and MINI Ireland staff working side-by-side to create this thriving green space.. The space is utilized to create recovery-focused programs, including mindfulness and yoga, while functioning as a social gathering area (7).

Mapinguari National Park, located in the Amazon region of Brazil, is a protected area distinguished by its rich biodiversity and vast expanse of untouched tropical rainforest (2). It was officially created on June 5, 2008, by decree, covering an area of 1,776,914.18 hectares (2). The Chico Mendes Institute for Biodiversity Conservation (ICMBio) manages the park. It is linked to a management plan encompassing several nearby conservation units and their areas of influence (2, 3). Its main goal is to preserve the valuable natural ecosystems and scenic landscapes of the Purus-Madeira interfluvial region, which includes savanna enclaves (2, 3). The ecoregion where it is located has a high priority for botanical conservation due to parameters such as species richness and endemism (3). Additionally, the area presents great environmental heterogeneity, with several isolated and unique ecosystems, aspects that have been considered for fostering scientific research and public visitation, with programs for environmental education, recreation in contact with nature, and ecotourism (3). On March 8, 2013, an advisory council for the park was established to involve various stakeholders in decision-making and the effective conservation of the park (2), and in 2018 a Management Master Plan was established, seeking to develop an integrated approach for the protection and proper management of the region, especially considering the socio-environmental impacts of the construction of the BR-319 highway and the deforestation caused by fires, the expansion of soybean cultivation, land appropriation (7) and cattle ranching from the neighbouring state (3, 10). It was established as a Natural Park in 2008, but over the years it has undergone changes in land regulations, adding or decreasing its size as certain mining activities have been allowed in the buffer zone (2)

The Digital Hub, a campus in Dublin 8 offering 49,000 sq. ft. of office, studio, and workspaces for small businesses in technology, creative industries, social enterprises, and artisans, has partnered with Pocket Forests to establish Ireland’s first urban native tree nursery. Located on The Digital Hub campus, the Pocket Forests Tree Hub will grow native Irish trees, including birch, rowan, and alder, to support the planting of over 600 trees throughout Dublin 8 and beyond.
As Dublin 8 district faces a noted lack of green spaces and low tree density, as highlighted by the Mapping Green Dublin project from University College Dublin and local groups, the Tree Hub is set to address this gap. This innovative initiative aims to improve the local natural environment and bolster biodiversity in a rapidly urbanizing area.
Pocket Forests, co-founded in 2020 by Ashe Conrad-Jones and Catherine Cleary, is inspired by the Tiny Forest concept, which brings diverse native plants to small urban plots. Using permaculture methods, Pocket Forests regenerates depleted soil and creates diverse micro-forests on plots as compact as six square meters. This approach, which enriches soil and encourages biodiversity, has a unique capacity to transform urban areas into lush, green spaces, contributing to improved air quality and local ecosystems.
The Covid-19 pandemic has underscored the importance of access to nature for well-being, and The Digital Hub offers an ideal location for this first-of-its-kind urban initiative. The Tree Hub will serve as a valuable resource for greening Dublin 8, promoting community engagement, and fostering a greater connection to nature.
Beyond the nursery, Pocket Forests will run a series of six half-day workshops at The Digital Hub to educate the community on biodiversity, pollination, compost, soil health, and the importance of urban forest ecosystems. The Digital Hub’s Tree Hub boosts well-being, biodiversity, and green space for future generations. (1-5

According to data from the National Institute for Space Research (Inpe), Rondônia ranks fourth nationally among the states with the highest number of detected fire outbreaks (2). In response to this issue and to restore devastated areas in the Amazon, Terra Cura was established in 2016 by resident Luana Lopes, promoting the planting of more than a thousand trees in the Porto Velho region (1). The areas benefiting from this initiative were those degraded by deforestation, causing erosion along the riverbanks (1).
This reforestation effort took place in the scenographic city of Jerusalem of the Amazon, from 2016 to 2022, a cultural and touristic complex in Porto Velho, where erosion caused by deforestation was observed along the riverbanks next to it (2). It was developed as a collaboration with the club and the founders of the Associação Clube Teatral Êxodo, who gave the space so that we could recover the land (3).
The project focused on developing an agricultural strategy known as syntropic farming, by implementing an agroforestry system. This approach seeks to reorganize and restore the natural environment, creating better conditions for planting and allowing trees to thrive. In the reforestation process, volunteers and experienced technicians worked together Additionally, the project included a nursery used for donating seedlings and for offering forestry and agro-construction courses to the community, held in the reforestation area (2).
The Terra Cura project, in addition to working on reforestation and recovery of degraded areas, promoted environmental and cultural integration at the site, promoting sustainable fairs and bazaars, training courses in ancestral practices such as soil cultivation and bioconstruction, and thematic events, bringing together artists and local communities (3). Although they were evicted from the area surrounding the scenic city of Jerusalem (5, 6), they are still active in the area.

"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].

The Santa Gilla lagoon, a crucial wetland in the Cagliari metropolitan area of Sardinia, has been the focus of several interventions aimed at restoring and preserving its natural and socio-economic functions. The overarching goal of these projects is to rehabilitate the lagoon's ecosystems, improve public accessibility, and promote sustainable economic activities such as eco-tourism and fishing. One significant intervention is the restoration of pedestrian and cycling paths around the lagoon, managed by CACIP (Consorzio Industriale Provinciale di Cagliari) in collaboration with the Metropolitan City of Cagliari. With over two million euros in funding, this project aimed to recover the original profiles of the lagoon's embankments, while removing waste from the area and enhancing the paths for non-motorized mobility (2). Another crucial development was the legal action taken by the Corpo Forestale (Forestry Corps) in 2020 to address illegal constructions and pollution along the lagoon's eastern shores. This action included the sequestration of areas used for illegal fishing activities, where hazardous materials and waste were improperly disposed of, leading to environmental degradation​ (1). Furthermore, environmental groups have made continuous efforts to address illegal dumping near the lagoon, particularly along the SS 195 highway. These groups have actively sought the intervention of local authorities to initiate cleanup operations and enforce regulations against illegal waste disposal​ (4). The projects were implemented primarily to address the significant environmental hazards facing the Santa Gilla lagoon, including pollution from illegal dumping, habitat degradation due to unauthorized constructions, and the overall loss of biodiversity. These activities also aimed to mitigate the socio-economic risks posed by the deteriorating environmental conditions, such as the decline in tourism and sustainable fishing practices (1,2,4).

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)

The environmental and public space recovery project around the Bazurto Market in Cartagena is a comprehensive initiative aimed at addressing the severe environmental degradation and chaotic urban conditions in this vital area of the city. The Bazurto Market, one of Cartagena's most important economic hubs, had experienced increasing levels of disorganization, pollution, and public health risks due to the encroachment of informal vendors and improper waste management (ref 1,2,5). The primary goals of this project are to restore the ecological health of the Caño de Bazurto and the Ciénaga de las Quintas, enhance the quality of public spaces around the market, and improve the overall urban environment (ref 1). Project activities included removal of waste from the surrounding water bodies, installation of protective barriers along the Ciénaga de las Quintas, and the planting of trees to revitalize green spaces (ref 3,4). Emphasis was placed on planting of a variety of tree species, such as Guayacán Amarillo, Ceiba, and fruit trees like níspero and mango. These efforts were concentrated in areas around the Bazurto Market, where green spaces had been neglected or overtaken by informal commercial activities. The project also included the restructuring of vendor locations and public spaces to reduce congestion and improve the flow of both pedestrian and vehicular traffic (ref 5). Educational campaigns were conducted to encourage better waste disposal practices and enhance community involvement (ref 1).