Soil remediation and revegetation

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.

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)

Martinique is a biodiversity hotspot, home to over 1,500 endemic plants, 70% of which are under threat from human activities. In response to these pressures, the Péyi Vert [Green Country] initiative was launched to plant endemic trees and strengthen the island's biodiversity. Beyond simply preserving species, these trees are crucial in maintaining healthy ecosystems, as they provide essential services such as carbon sequestration, shade, food for human consumption, soil decontamination, pollination, and protection against coastline erosion.
Launched in June 2020 by Entreprises et Environnement (EE), a not-for-profit business association representing 80 Martinican companies, the Péyi Vert initiative aims to plant 1 million native trees (either Martinican or Caribbean) over five years. It can be seen as a Martinique-wide strategy to adapt to and mitigate climate change. Péyi Vert facilitates connections between people who want to plant trees and Martinican companies that serve as financial sponsors. The initiative emphasizes conserving natural heritage by planting endangered species, as well as promoting native species that, while not necessarily threatened, provide valuable ecosystem services or contribute to biodiversity restoration.
Between 2020 and 2023, EE reported planting 50,000 trees (Refs 1, 4, 6, 7). Although individuals can make donations, Péyi Vert primarily seeks funding from companies looking to offset their carbon emissions or enhance their Corporate Social Responsibility (CSR). To achieve its goals, the initiative mainly collaborates with municipalities, companies, and farmers (Ref 3).

Herboristerie Créole, established in 2012 in Martinique by Séverine and Rémi Asensio, is a private farm and business focused on cultivating aromatic and medicinal plants, managing all stages of production, processing, and marketing. Situated in the commune of Gros-Morne, the farm draws on traditional Creole knowledge to produce medicinal plants and Creole cosmetics. Spanning 1.8 hectares, it is organized as a forest garden, featuring a diverse ecosystem that includes aromatic and medicinal plants, spices, fruit trees, and tropical flowers. Agroecological practices are central to its operation, with natural mulching from coconuts and green waste, and composting from the forest garden enriching the soil.
In addition, Herboristerie Créole operates a certified organic herbal dispensary in Saint Joseph, specializing in medicinal plants. The dispensary merges ancestral knowledge from the local "Rimèd Razié" tradition—a practice involving the use of native plants and natural remedies for healing, passed down through generations—with modern pharmaceutical standards. It produces a range of products, including herbal teas, infusions, spices, oils, and capsules for pharmaceutical and cosmetic use.
The farm is instrumental in preserving and passing on ancestral knowledge, which was once banned during the period of slavery, while ensuring that its artisanal products comply with dosage and safety regulations. Located at the foot of the Carbet peaks, the farm holds the Biological Farming (AB) label and follows agroecological methods through its "Jardin Créole" approach. It avoids the use of phytosanitary products, aims for zero waste, and implements measures to preserve biodiversity. (ref. 1, 2, 5, 6)

Rapid urbanization and a population density of 6,247 people per km² have placed significant stress on Nairobi's natural resources (Ref 1). The 40-km long Nairobi River Basin, originating from the Ondiri Swamp, serves as a vital water source for the city (Ref 1, 2). However, it has suffered severe pollution from untreated sewage, solid waste, industrial contaminants, plastics, and agricultural runoff (Ref 1, 3). This degradation has had a serious impact on the ecosystem, local residents, and biodiversity (Ref 3).

To address these issues, the Nairobi River Basin Programme (NRBP), sponsored by UNEP, was launched in 1999 (Ref 4). Since then, government and non-state actors have worked together on solid waste management, riparian restoration, and wastewater control (Ref 1). The program was implemented in two phases: Phase I (2003–2006) and Phase II (2006–2009), involving stakeholders from the government, private sector, and civil society (Ref 1, 4, 5). Despite these efforts, a study from 2017 found significant tree removal along the river, and between 1988 and 2014, encroachment into the 30-meter riparian buffer zone dramatically increased, particularly between 2010 and 2014, further degrading the river’s health (Ref 1).

The increasing volume of solid waste, driven by Nairobi's growing population, has become one of the city's major challenges (Ref 1, 2). To address this issue and promote better environmental practices, authorities plan to convert all reclaimed illegal dumpsites into recreational and green spaces. The transformation of the former Kangemi Cemetery, abandoned for over 20 years and used as an illegal dumpsite, was the first initiative in this effort.
Led by Nairobi's Governor, H.E. Mike Sonko, and supported by the City County, the project was completed in 2018 and serves as a key example of these transformative measures (Ref 1, 2, 3). Previously, Kangemi Cemetery contained over 500 loads of illegal waste, but following a successful clean-up, it has been rehabilitated into a children's playground with recreational area, now named Kangemi Cemetery Memorial Park (Ref 3).

The John Michuki Memorial Park was transformed from a vast dumpsite in 2008 and established in honor of John Michuki, the Environment Minister during the Kibaki administration, in 2012. Michuki garnered admiration and accolades for his enthusiasm and determination to clean and preserve the environment (Ref 1, 2). Situated along the Nairobi River, the park serves as a historically rich recreational facility (Ref 3).
However, several issues arose after the park was transferred to the county administration in 2013 (Ref 2). A section of the Nairobi River flowing through the park experienced severe environmental degradation due to illegal discharges and poor waste management, negatively impacting the riparian ecosystem and biodiversity (Ref 4). Additionally, the park became a refuge for drug users, street children, and thieves, with stray dogs posing safety threats in the area (Ref 1, 2).
As the first project within the Cleaning Up Kenya Campaign, the restoration of Michuki Memorial Park was launched in 2020 by the government (Ref 5). The park is now managed by the Kenya Forest Service (KFS) following a directive from the national government (ibid.). With funds from the treasury, a perimeter fence was erected, a 2.4 km walkway was constructed, and 4,200 seedlings and 6,357 indigenous trees were planted, along with the establishment of a nursery (Ref 1, 6). A total of 20,000 tons of solid waste were removed (Ref 6). Additionally, a community forest association was formed to ensure community engagement (Ref 2).

Ngong is a town in southern Kenya, located near Nairobi in Kajiado County, on the slopes of the Ngong Hills. The municipality has experienced significant development and population growth due to improved infrastructure and social amenities. However, this expansion poses a threat to biodiversity, as increased demand for agricultural land, wood, and raw materials is depleting the area's forests and putting many species at risk of extinction. Overgrazing, illegal logging, invasive species, and climate change-induced extremes like droughts and floods have further exacerbated the situation.

In response, the Rufford Foundation proposed the Improving Ngong Hills Forest Conservation Efforts through Raising Local Community Awareness of Biodiversity Conservation project. The initiative seeks to restore the Ngong Hills forest ecosystem through community-driven conservation. A nursery for native species was established, and tree planting campaigns were conducted in collaboration with national and local governments, community-based organizations, indigenous groups, and schools. Additionally, awareness programs and capacity-building efforts were launched, engaging local schools in restoration activities and organizing workshops to train community members and officials. (Ref. 1, 2, 3, 4, 5)

To protect the Lomas de Primavera from urban pressure and other threats, the Lomas de Primavera Ecological Association has implemented strategies for its conservation. One of the strategies this organisation has promoted is reforestation activities. Working together with the Municipality of Lima and other interested actors, they have sought to expand Lima's green spaces, improve air quality, enhance flora, and promote tourism, among other benefits (1). Lima's Municipality has supported the project by donating 20,000 trees for reforestation and to prevent land encroachment (1), social organisations and environmental activists have joint efforts to plant more than 250 trees to support the conservation efforts (2, 7).
The Lomas de Primavera Ecological Association leads the project, organizing community management efforts to conserve the Lomas de Primavera sector. This association is based in the Agrupación Familiar Primavera Lomas de Carabayllo community (2). The association's conservation activities involve collaboration with various stakeholders at different levels. Locally, it works with community leaders and organizations. At the district level, it coordinates with the Carabayllo municipality and the NGO CIDAP to improve urban conditions. The metropolitan-level collaboration includes the Municipality of Lima and the ACR 'Sistema de Lomas de Lima' for ecosystem protection and valorization. Nationally, it partners with MINAM, SERNANP, MINAGRI, UNDP, UCV, and the Network of Peruvian Lomas to enhance ecosystem services, restore degraded areas, and conduct research on the Lomas (2).
The preservation and reforestation of these ecosystems is essential, as they have social, cultural and environmental value, including the following ecosystem services: provision of genetic resources, soil formation, pollination, aesthetic services, ecotourism, food, education, and archaeological and historical services (3)

This initiative was launched by the local government of La Paz, focusing on afforestation of the Mallasa landfill, which was closed in 2004 (1-4 & 6-10). While some plantations were established in the area when the landfill was closed, the overall plan aimed to manage the waste until the site was sufficiently clean for new projects—a process expected to take at least a decade (6). By 2021, signs of biodiversity, including flora and fauna, had begun to return to the former landfill. In response, the municipality of La Paz implemented a project to plant 6,000 native tree species, along with other shrub species, to further enhance biodiversity regeneration and establish a second urban forest in the city (3 & 4 & 7 & 8).

The afforestation efforts took place between 2021 and 2022, coordinated through "forestry brigades" made up of diverse volunteer groups. These groups included members from public institutions, private company representatives, NGOs (both environmental and non-environmental), universities, religious organizations, and local citizen groups (8-10). A total of 12 hectares were reforested out of the 33-hectare area (1 & 7). Following this, the area was closed to the public and is expected to become a biodiversity sanctuary within ten years, with ongoing monitoring by the municipal environmental agency (7). Among the trees planted, some were chosen to attract birds with their fruit, others to support the pollination of hummingbirds and bees, while others were intended to enrich the soil with nutrients—all species being native to the region (3 & 7).

Additional goals of the initiative include raising awareness about climate change, fostering a sense of environmental stewardship through community engagement, and advancing the municipality's decarbonization plans (3 & 9). Some of the seedlings and saplings were purchased by the municipality at a cost of 6,160 euros, with private companies also contributing financial support to the initiative (1 & 7).