Cultural heritage and cultural diversity

The Mobile Tree Trail is a nature-based solutions (NBS) initiative aimed at preserving Mobile, Alabama’s urban forest while celebrating its cultural and ecological heritage (Ref 1, Ref 2). First established in the early 1990s by volunteers, the original trail featured 24 iconic trees, selected for their historical significance, environmental value, and beauty (Ref 1, Ref 2). Over the years, some trees were lost to development and storms, and the trail faded into obscurity (Ref 1, Ref 4).
From 2021, the Mobile Tree Commission, with support from The Nature Conservancy, is leading efforts to revive the trail (Ref 3, Ref 6). Activities include reviewing past entries, opening public nominations, and selecting new trees that best represent Mobile’s identity (Ref 3, Ref 4). The project emphasises inclusivity and public participation, welcoming volunteers and local input to shape a trail that evolves with the city (Ref 4, Ref 6).
Mobile faces environmental threats such as hurricanes, urban expansion, and loss of native tree cover (Ref 1, Ref 6). The revitalised trail helps address these challenges by promoting awareness, conserving old-growth specimens like the 300-year-old Duffie Oak, and maintaining vital green spaces (Ref 4, Ref 6).
The Mobile Tree Trail blends education, tourism, and conservation, enhancing urban resilience while telling the city’s story through its trees (Ref 3, Ref 6).

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 stretch of the Great Lakes basin ecosystem from southern Lake Huron through western Lake Erie forms a unique urban refuge where life thrives with beauty and resilience. Known as Metropolitan Detroit, this region is where the Community Foundation for Southeast Michigan and many partners are working to create The Great Lakes Way by connecting 160 miles of greenways and 156 miles of water trails (1).
The vision for the Great Lakes Way project is to ensure that all residents and visitors of southeast Michigan—people of all ages, backgrounds, ethnicities, abilities, and interests—feel connected to the water resources, welcomed on its trails, and able to enjoy the benefits and opportunities these access points provide (1). To bring this vision to life, the project plans to link 160 miles of greenways and 156 miles of blueways, connecting people to a range of world-class freshwater, wildlife, and recreational opportunities. These include fishing areas, bird migration pathways, parks, working waterways, preserved woodlands, and restored wetlands (2).
The Great Lakes Way project connects existing assets, supports accessibility and equity, and promotes the Great Lakes Way to both residents and visitors through marketing and communication efforts (2). There are 26 points of interest that will serve as connection hubs along the Great Lakes Way (2). In Detroit specifically, the focus is on connecting 13 culturally or historically significant destinations, as well as locations known for their environmental and ecological importance or as regional landmarks (2).
Rich in world-class fisheries, migratory flyways, parks, urban centers, small towns, preserved old-growth woodlands, and restored wetlands, the Great Lakes Way offers unique experiences that can only be found here. By uniting the natural and cultural assets the Great Lakes Way designation aims to emphasize and expand the essential linkages needed to further connect this remarkable region. (2,3)

Located between the Rotes Rathaus, Karl-Liebknecht-Straße, Nikolai Quarter, Spreeufer and the television tower, the old founding centre of Berlin is one of the capital's most important urban open spaces. This open space between the TV tower and the Spree is being redesigned on the basis of an international open space planning competition and many years of public participation. With further development, this touristically significant location in the historic centre of Berlin will undergo a climate-resilient redesign and upgrade with great design and functional quality. (Ref. 1)
The listed areas of the Rathausforum and the Marx-Engels-Forum will in future be connected to form a continuous ribbon of open space that runs from Alexanderplatz to the Spree. Central areas will be unsealed and green spaces will be created that can be used in a variety of ways, which will also be attractive places to spend time and improve the microclimate. Trees and shrubs will be planted on already existing and new green areas. The aim is to respectfully consider the numerous visible and hidden historical references and at the same time transform the site into a sustainable urban open space that combines a high quality of recreation, sustainability and culture. Next to plants, a new rainwater management system is being implemented that stores rainwater and uses the created green spaces to evaporate water. Playgrounds and a water fountain are further additions to a new recreational area. (Ref. 3; Ref. 4; Ref. 5)
The project is characterized by a years-long participation process. Around 10.000 citizens participated in feedback rounds, workshops, dialogues, and information sessions in which they could voice they wishes and ideas for the area. The project is implemented and organized by the state-owned company Grün Berlin, which engage with various stakeholders since 2015. Preparations for the construction start in late 2024 and the project is expected to be finished in 2030. (Ref. 5; Ref. 9)

For thousands of years the Rio Salado, also known as the Salt River, and its larger mainstem, the Gila River, served as an important perennial source of life and growth for indigenous people residing in central Arizona, including the Akimel and Piipaash (3). Today, the Salt River is an ephemeral river corridor connecting diverse urban communities across an expansive and growing Maricopa County (3). While the river is now typically defined by intermittent flow as a function of water conservation and distribution in an arid urban climate, it also has powerful flows during the Arizona monsoon season providing a diverse and unique ecosystem for the region (3). To foster the health of the River, a regional multi-decade project was initiated in 2018 called Rio Reimagined, which includes six cities and two tribal communities (1). Rio Reimagined is a planning initiative in a very early concept stage, centered around the mission to support and enhance this treasured river corridor (3). The goals of Rio Reimagined consist of connecting communities, Equitable & Sustainable Development, and Restoring and Revitalizing Healthy Rivers (3). As part of the Rio Reimagined, the City of Phoenix founded a collaborative project called Rio PHX that will help promote a 20-mile Rio Salado (Salt River) corridor as a local and regional destination that attracts positive investment for the benefit of existing/future businesses, residents, and tourists (1). The final aim with this project is to improve health outcomes for existing and future residents by address outstanding needs in the area and create opportunities for housing, employment, recreation, art, and ecological restoration (1). From May 2024 to May 2025 Rio PHX will engage in creating a community profile, an existing conditions assessment, community engagement & visioning, developing implementation strategies and drafting the master plan (1). Public hearings and final plan adoption are set to take place in fall 2025 (1).

Located in the municipality of Morne Rouge, the Domaine d’Émeraude was once an agricultural site but was transferred to the Martinique Regional Natural Park (PNRM) in the early 2000s. It underwent significant renovations in 2005 to transform it into a sanctuary for Martinican biodiversity, reflecting the need to protect and conserve the island's unique ecosystems. In 2011, it opened its doors to the public, serving as an important educational resource that raises awareness about the island's historical, natural, and cultural heritage (Refs 4, 7, 8).
Today, the site encompasses 25 hectares protected from anthropogenic pressures and is primarily characterized by a humid tropical forest environment, which makes up 80% of the area (Ref 7). It is home to over a hundred native species (Ref 4) and offers nearly 4 kilometers of walking trails accessible to both adults and children, complete with recreational stops and educational amenities.
The Domaine d’Émeraude was designed to enhance the conservation of native species while developing sustainable economic activities that benefit the local community. Moreover, the site emphasizes the well-being that forested areas provide to visitors, highlighting that "the air can be heard, the smells can be savored, and the sounds can be experienced. The freshness of the place is a source of change and relaxation..." (Ref 4).

In Berlin, at the palace park and garden Charlottenburg, approx. 40 to 70 horned Gotland sheep are used to maintain the grass fields and meadows. The project is part of a garden and landscape conservation programme that is to be seen as a contribution to practical nature conservation by the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, which manages the park. From May to November, the sheep are grazing on the palace property, whereby the exact length of time the sheep are kept and the duration of the project depend largely on the developing weather conditions. This is because prolonged drought significantly reduces the growth of the grasses. (Ref. 1)
The garden had already been grazed earlier in its history, but no longer in the post-war period. The garden was created by Electress Sophie Charlotte in 1695. (Ref. 3) Since 2018, sheep can be found again in the park space where they graze on extensive meadows with groups of chestnut, lime, maple, oak, beech and solitary trees. At the beginning of May, they move into their first station there, usually the meadow in front of the late baroque-classical Belvedere tea house. Once this has been grazed, they move on to the next meadow; with an area of 55 hectares, there is plenty of pasture. (Ref. 4)
Sheep from his flock also graze on the green flat roof of the Max-Schmeling-Halle in Pankow, the palace garden of Sanssouci and other public and private patches of land around Berlin. Reasons to use sheep over machinery for the maintenance of the park space are monetary and a reduce loss of biodiversity. Sheep are cheaper compared to machinery, the needed labour and wear, and also don't kill insects living in the fields as machinery does. Furthermore, the sheep dung fertilises the grass area, sheep limit the spread of invasive plants and are more gentle to the soil. At the same time, palace visitors enjoy observing the sheep and can learn about them in guided tours. (Ref. 4; Ref. 6)

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].