Enhanced carbon sequestration

The City of Seville has carried out four tree planting campaigns between 2020 and 2024, aiming to meet the goals of its Urban Tree Management Plan for Seville [Ref. 2-7]. The intervention as described here is based on the planting campaigns to date, but as the Management Plan spans from 2019 to 2039, more campaigns can expected in the future. The tree management plan aims to provide guidelines for the planning of trees in the city to maximise their value and minimize conflicts. As part of the process, the current state of the tree population in Seville has been evaluated. The management plan describes the ecosystem services of trees related to climate adaptation, biodiversity and public health. It also identifies challenges and conflicts that may arise due to urban trees and their management [Ref. 1]. The plan has a goal to increase the tree cover in Seville by 5 % over 20 years, which leads to the ambition of planting 5000 trees yearly and the tree planting campaigns over the last years. Between 2020 and 2024, about 1000-5000 trees have been planted each year [Ref. 1-5].

Phoenix is America’s fifth largest and hottest city, a sprawling urban heat island which has expanded without adequate consideration to climate and environmental factors like water scarcity and extreme heat (1). ​Multiple heat records were broken in 2023 including 133 days over 100F (37.7C), and 55 days topping 110F (43C) (1). Only around 9% of Phoenix is protected by tree canopies, yet this citywide figure masks vast inequities between wealthy, majority-white neighborhoods (1). As a response, the City of Phoenix has adopted an equity-driven heat mitigation plan to create a shadier, more livable environment amid rising temperatures and hundreds of heat-related deaths (1). Part of this plan created the Community Canopy Grant program, which offers public schools, churches and homes in qualifying census tracts – low-income neighborhoods with little shade funds for tree planting projects (1). One neighborhood, Grant Park is one of the city’s oldest neighborhoods – and one of the most neglected (1). It is a red lined neighborhood with higher pollution levels, less vegetation, more noise pollution and higher temperatures (1). To change the inequity and create enough shade to provide residents and passersby reprieve from the heat, the city planted around 40 trees in the Grant Park neighborhood within household yards (1-2). Residents can choose from a list of 19 native and desert-adapted trees including the Texas olive, Chinese red pistache and Chilean mesquites (1). The trees, which are a couple of years old and pretty heavy, are planted by contracted arborists (1). Following the planting process, each household was provided with a tree kit – a hose, irrigation timer and instrument to measure the soil pH and moisture, as well as written care instructions (1). This is the fourth tree planting effort by this city and the hope with this initiative is that it lasts (1).

‘Grün macht Schule’ has been informing, advising, and supporting schools and school initiatives in Berlin since 1983 in the planning and realization of schoolyard projects. The program focuses on improving school playgrounds by creating child-friendly, natural habitats and ecological learning spaces, making schoolyards better equipped to address climate change. In 2012, the program expanded with the launch of the ‘Grün macht Schule - KinderGARTEN’ funding initiative, which extended support to kindergartens.
Over the past four decades, with the program’s assistance, Berlin has seen the transformation of large, unstructured schoolyards into smaller, creative playgrounds. These spaces now feature imaginative and artistic objects alongside facilities for play, exercise, and communication. Additionally, many school gardens and biotopes have been established or restored, turning school grounds into vibrant ecological and educational environments .
The projects are largely driven by schools’ self-initiatives, with ‘Grün macht Schule’ offering support throughout. This grassroots approach fosters pride and a sense of ownership among school communities, strengthening their identification with the results. The collaborative effort also enriches educational practices, promoting inclusion, integration, and democratic participation. Such initiatives offer a hands-on experience with sustainable climate protection projects, making these efforts tangible and impactful in everyday school life.
In addition to its project-based support, ‘Grün macht Schule’ provides training for school teams, organizes regional and national conferences, and hosts seminars and lectures to share best practices and inspire further action .
The program is a cooperative effort between the Senate Department for Education, Youth and Family and the association Freilandlabor Britz e.V., operating under the guidance of the Senate Department. (Ref. 1-4, 6)

As heat waves and high temperatures intensify due to climate change and urbanization, the City of Phoenix is exploring how to reintroduce tree shade into urban spaces to create a more equitable, livable environment. In 2014, the city set a goal to shade at least 25% of Phoenix by 2030, known as the Tree and Shade Master Plan. Achieving this ambitious target requires substantial resources and active community participation.
A key player in this initiative is Trees Matter, an environmental nonprofit dedicated to helping Phoenix reach its shade goals. Trees Matter not only works to expand and sustain the city’s tree canopy but also aims to foster environmental equity. Among its initiatives, the Trees for Schools program promotes tree planting in schools while educating staff and students about the significance of trees and tree care.
Silvestre Herrera Elementary School is one example where the Trees for Schools program has made a direct impact. As part of this program, 30 trees were planted on the school grounds, involving students, staff, and community volunteers in the process. These new trees offer critical environmental benefits, including shade, air purification, dust reduction, food production, and carbon sequestration. Additionally, tree presence has been linked to improved physical and mental health outcomes.
Beyond the immediate environmental gains, the project also offers educational value by involving students, staff, and maintenance crews in hands-on learning about tree care and environmental stewardship. This approach ensures that participants are equipped with the knowledge and skills needed to care for the trees long term, reinforcing both sustainability and community resilience.
Through these combined efforts, Phoenix is making strides toward a greener, more shaded future—one that benefits not only the environment but also the well-being and health of its residents. (1-5)

Planting Oxygen in the Community is an initiative initiated by the medical company Antibiotice S.A., one of the largest drug producing company in Romania, with headquarters in Iasi. The initiative involves an annual tree plantation campaign that has been carried out over the past four years. Originally implemented in cooperation with the municipality of Iași, the campaign is now independently managed by the medical company Antibiotice S.A. The selected planting area is located adjacent to the company headquarters in Iași and consists of undeveloped grassland.
Throughout the campaign, a total of 1,175 trees and 6,000 shrubs have been planted, including species such as oaks, lindens, and maples. The initiative has engaged 310 volunteers from the company to assist with the planting efforts.
The campaign aims to achieve several goals: rehabilitating green spaces, protecting the environment, reducing carbon emissions, mitigating the effects of climate change, and providing cleaner air for future generations. Additionally, it seeks to enhance the company’s environmental impact and foster social interaction among employees by reconnecting them with nature.
(1-8)

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

The reforestation project at Bela Vista Park in Lisbon is a collaborative effort by the MEO Kalorama music festival, the Lisbon City Council, and Quercus (local NGO). The intervention began with a community planting event in February 2024 with the planting of 80 native trees, and the goal to plant a total of a total of 1,000 trees. The project aimed to improve the park's biodiversity, enhance carbon absorption, and support local wildlife. The tree species were chosen for their suitability to the local climate and their ability to integrate with existing vegetation. Local schoolchildren and residents participated in the planting, serving as a community engagement activity. This initiative is part of broader efforts to make Lisbon greener and to positively contribute to the local environment, given the disturbance caused by the MEO Kalorama festival (Ref 1, 2, 3).

Since the 1980s, the Graefekiez neighborhood in Berlin's Friedrichshain-Kreuzberg district has been a traffic-calmed area where all road users are treated equally, driving is limited to walking speed, and cars are permitted to stop anywhere. However, this once-progressive concept no longer functions effectively due to the significant increase in cars and delivery vehicles over the years. The streets no longer resemble a traffic-calmed zone, with traditional layouts featuring roadways, sidewalks, and parking spaces. As a result, many users fail to recognize the traffic-calmed nature of the area, leading to safety issues: vehicles drive too fast, delivery traffic causes conflicts, and streets are difficult to navigate safely.
Berlin’s transport sector faces the challenge of meeting legally mandated CO₂ reduction targets. Achieving these goals requires bold measures, including limiting private motorized transport (MIV), especially in densely populated areas where residents and visitors have access to alternative modes of transportation.
The "Graefekiez" project addresses these challenges through urban redevelopment aimed at improving livability and promoting sustainable urban mobility. Car parking has been banned from the streets, freeing up space for communal use such as lounge areas. As part of the "Graefekiez" project, the district office is converting parking spaces into green spaces and expanding tree disks to adapt to the climate and promote a sponge city.
The project was developed collaboratively with residents and NGOs through a participatory process led by the Friedrichshain-Kreuzberg district office, in partnership with the Berlin Social Science Center and Paper Planes e.V. Implementation began in 2023 on Graefestraße and Bockhstraße.After a six-month trial period, the district office decided in 2024 to make the measures permanent.
This initiative advances a safer, greener, inclusive urban environment while meeting climate and community goals. (Ref. 1, 2, 3)

Parque Lácides Segovia is an urban park located on Isla de Manga in Cartagena, Colombia. The park was inaugurated and revitalizated in June 2014 to serve as a multifunctional green space promoting cultural, social, and environmental activities. Named after General Lácides Segovia, a notable figure in Cartagena's history, the park aimed to provide a family-friendly and culturally enriching environment (ref 1). The primary goal was to transform a neglected urban area into a dynamic public space that fosters community interaction and enhances local culture. The park aimed to create a safe, inclusive, and accessible environment for residents of all ages, promoting social integration and cultural activities. Additionally, the project sought to establish a green area contributing to the ecological health of the city through urban greenery (ref 1, 2).
The first revitalization in 2014 involved facilities, planting native trees, and setting up public amenities such as Wi-Fi, seating, and cultural spaces(1, 2, 3).
This new revitalization in 2024, led by the local government of Cartagena, will focus on enhancing the infrastructure of both the park and the surrounding sports area in Manga to improve sustainability. The project has an estimated budget of approximately USD 675,000. The improvement works to provide better facilities and infrastructure to support recreational and sports activities, benefiting the community and promoting a healthier urban environment (ref 6). The park is essential for the community; it was recently the subject of several citizen science projects led by the Montessori School, including research identifying the park's ecosystem services (ref 3).

Two new wetlands were established in Dodder Valley Park as part of the Dublin Urban Rivers Life Project (DURL). This project aimed to create integrated constructed wetlands (ICWs) at strategic locations in South Dublin County to purify wastewater and storm-water before it discharged into rivers.
The ICWs consisted of a series of cells resembling shallow ponds, typically 200 to 300 mm deep. Heavily planted with specific vegetation, these cells treated water by removing nutrients and harmful impurities, resulting in cleaner, purer water being discharged. The water flowing into the wetlands came from wastewater of misconnected appliances and storm-water pipes located under public roads, which collected rainwater from roads, footpaths, and the roofs and patios of houses.
These wetlands also provided important benefits, including flood alleviation, bioretention of particulates and nutrients, improved habitat conditions, and enhanced biodiversity. The project aimed to promote the relationship between green infrastructure and public well-being, creating a complex biological system that supports a diverse range of plants, animals, microorganisms, and hopefully attracts frogs, newts, and birds.
To increase native biodiversity, the wetlands were designed with pollinator-friendly plants and trees, making them visually appealing for park users and the public. A Wetland Planting Day took place on September 9, 2022, with over 40 participants, including residents and representatives from local organizations. This phase of the project fulfilled not only the objectives of the LIFE project but also those of the River Basin Masin Management Plan 2022–2027, the Water Framework Directive, the Climate Change Action Plan, the Floods Directive. (1, 2, 5)