Vacant or abandoned land

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).

Public spaces in Colombo are disappearing due to rising land prices, causing infrastructure issues that harm citizens' health, especially in low-income areas (3). One proposed solution to address the problems caused by rapid urbanization is the creation of community gardens, which can at least improve low-income residents' diets and immune systems and address malnutrition (3).
Considering the limited urban space for both citizens and other living beings, the organization Eco-friendly Volunteers decided to create a community garden. The Metta Garden in Colombo (1, 2) aims to bring back urban biodiversity through organic home gardening, generating healthy food for people and creating living space for many other animals and plants (2). Following the Buddhist concept of Metta (loving-kindness to all beings), it promotes walking meditation paths and facilities to experience nature using all five sensory organs (1), in addition to being a place for experiencing loving-kindness for both human and non-human living beings, seen and unseen (4, 5).
It has become a training institute for many stakeholders seeking to grow organic food and earn a better income through the high demand for organic products (2). At the same time, it serves as a biodiversity spot, attracting butterflies, bees, and other forms of wildlife to an urban environment (2).
The area is located in the middle of a semi-urbanized area, on the outskirts of Boralesgamuwa (2, 3). Maintained by a group of volunteers, it features a greenhouse and a plot of land of around 5,000 sq feet, populated with vegetable patches, a butterfly garden, flowers and rare medicinal plants (3, 4). The garden was divided into four sections representing the Buddhist elements: water, heat, air, and solid. Each section features specific plants and designs, like a pond for water, a compost pit for heat, tall plants for air, and a rock garden for solid. The layout follows a mandala design based on permaculture principles (4).

The environmental impact of golf has led to growing calls to make the sport more sustainable (1). Golf course maintenance often involves carbon-intensive fertilizers, frequent mowing, and, in some cases, the clearing of forests or trees that naturally absorb carbon dioxide to make room for expansive fairways (1). However, the Tournament Players Club (TPC) Michigan is working to create courses that benefit both golfers and the environment (2).
Fifteen years ago, the site was a neglected floodplain along the Rouge River, initially purchased by Henry Ford in 1915 and once littered with community waste and old motor parts from the Ford Motor Company (2-3). Today, it has been transformed into an 85.8-hectare course that supports a diverse range of wildlife, including birds, fish, foxes, and coyotes (2). Led by Jack Nicklaus, the restoration aimed to turn this former waste site into an eco-friendly course (2). With guidance from Audubon International, the course was converted into a wildlife sanctuary, becoming the world’s first golf course to receive the prestigious John James Audubon Environmental Steward Award for ecological restoration (2).
TPC Michigan features native Michigan plants, such as viburnums, which produce berries for wildlife, along with various native grasses (2). To prioritize environmental stewardship, the course managers have created buffer zones to protect natural habitats and conserve water by using coring methods to monitor soil moisture (2). Pesticide use is minimized; instead, staff monitor for signs of disease or pests and test the soil to determine the specific nutrients needed for the turf (2). The course’s links-style layout includes rolling fairways, tiered greens, and natural wetlands, with tee options ranging from 5.5 to 6.4 meters (4). By establishing a wildlife sanctuary, TPC Michigan offers golfers a unique experience that fosters a connection with nature (3).

Across Detroit, neglected properties and vacant lots are a common sight (1). Nearly three-quarters of Detroit residents report that there is currently deterioration—defined in the survey as a building or property visibly declining due to long-term neglect—in their neighborhoods (1). One organization, Rescue MI Nature Now, a Michigan nonprofit, is dedicated to transforming these neglected areas into beautiful, functional spaces that benefit both people and wildlife (2).
In 2022, the organization purchased property from the Detroit Land Bank that was marked for demolition (3). Following extensive renovations, the building—now named the Innovative Youth Studio—has become a hub for multiple community initiatives. These include a community garden across the street, a culinary studio that teaches young people how to prepare nutritious meals, a pollinator studio that educates on the critical role pollinators play in the food chain, and a hydroponic studio where plants are grown using nutrient-rich water instead of soil (3).
The pollinator project, developed in partnership with the U.S. Fish & Wildlife Service, supports small bee colonies by planting areas with trees, flowers, and native plants (2). To further enhance biodiversity and support butterflies, bees, and birds, Rescue MI Nature Now partnered with Bowling Green State University to gain insights into pollinator biodiversity and habitat potential (2). Through this initiative, the organization aims to raise awareness about pollinators, highlight their positive impact, offer guidance on creating pollinator-friendly spaces at home and enhance the quality of life for local residents and communities (2).
Additionally, the organization runs a Sustainable Youth Stewardship Program, where young people learn to garden, grow trees, identify various plants and invasive species, and practice conservation skills such as creating pollinator habitats and managing community gardens (3).

The former Kulturpark Plänterwald, once the only permanent amusement park in the GDR, closed in 2001 due to declining visitor numbers. Over time, the 23-hectare site became a ‘lost place,’ falling into disrepair. In 2014, the state of Berlin reacquired the area, and two years later, Grün Berlin initiated its redevelopment with a sustainable development concept that places significant emphasis on rainwater management.
The project’s goal is to avoid discharging rainwater into the sewer system and instead manage all precipitation on-site. This approach addresses both heavy rainfall events and extreme drought conditions, creating a sustainable rainwater management system. A central element of this concept is the historic but dried-up water basin located near the iconic Ferris wheel. Plans include redesigning and reactivating the basin, incorporating terraces and a shallow water zone, transforming it into a key part of the rainwater cycle while providing an attractive recreational and adventure area. (Ref. 1; Ref. 2)
In the future, the water basin will no longer be purely decorative but will serve as a critical artificial water reservoir. To support this function, it will be equipped with a natural horizontal filter system featuring reeds for rainwater purification. Pre-treated water will flow into the newly designed 3,000-square-metre basin near the Ferris wheel. Rainwater collected in the basin, along with water stored in cisterns throughout the park, will irrigate the site’s vegetation. This innovative approach ensures sustainable water use and contributes to the ecological revitalization of the park. (Ref. 1; Ref. 3)
By integrating sustainable rainwater management into its redevelopment, the former Kulturpark Plänterwald is being transformed into a resilient and environmentally conscious space, combining historical preservation with modern ecological practices.

The Gnomes Project was launched to breathe new life into the abandoned Dublin City University (DCU) Community Garden, transforming it into a thriving urban micro-farm. Led by three friends—Martin, Jason, and Shane, collectively known as "The Gnomes"—the initiative grows pesticide-free, organic produce for the local community while championing regenerative farming practices.
The Gnomes employ bio-intensive agriculture, a sustainable approach designed to maximize yield from small spaces while maintaining biodiversity and enriching soil health. This method supports long-term productivity by promoting crop diversity, improving soil quality, and reducing dependence on external inputs through a closed-loop system.
The project’s journey began in 2015 when Jason and Martin enrolled in DCU's horticulture program and saw potential in the overgrown community garden. Shane joined as a volunteer in 2016, and by 2017, the trio had formalized their efforts to revitalize the garden. In 2019, they registered their business and began growing over 30 types of crops, eventually selling their produce through local farmers’ markets and small businesses.
Working tirelessly to restore the garden, The Gnomes cleared debris and removed invasive weeds using organic methods, transforming the area into a productive micro-farm. After negotiating with the university, they secured a lease for a 10,900 sq.-ft. plot (approximately 1/4 acre), with access to water. This space became the foundation for their bio-intensive, small-scale farming model, enabling them to grow quick-yield, high-value crops that thrive in limited spaces.
Some of their 20+ crops include a variety of leafy greens, herbs, tomatoes, cucumbers, zucchinis, green beans, onions, carrots, beetroots, baby turnips, apples, and recently added microgreens.
The Gnomes Project demonstrates the potential of urban farming, combining sustainable agriculture with community engagement. (2-5, 7-10)

The Fenkell Stormwater Project in the Brightmoor neighborhood of Detroit is an initiative led by the Detroit Water and Sewerage Department (DWSD) to mitigate the impact of heavy rain events on the local sewer system. By transforming 92 Detroit Land Bank Authority (DLBA) parcels into 24 bioretention gardens, the project aims to significantly reduce street flooding and basement backups in the area. These gardens, spread across approximately 50 acres of mostly vacant land, utilize permeable soils and landscaping techniques to absorb excess rainfall, which helps prevent the overloading of the city’s combined sewer system. This is particularly important in reducing combined sewer overflows (CSOs), which occur when the system's capacity is exceeded during heavy rains, leading to untreated stormwater and sewage being discharged into the Rouge River.
The project is expected to manage and treat about nine million gallons of stormwater annually, making a significant impact on both the neighborhood’s infrastructure and the environment. In addition to the bioretention gardens, the project includes the partial removal of Blackstone Street between Keeler and Midland streets to further enhance stormwater management.
Community engagement has been a critical component of the project, with residents of Brightmoor and Minock Park participating in meetings to share their preferences for the types of trees, plantings, and other features. The DWSD will maintain the gardens under its Green Stormwater Infrastructure (GSI) program, which already includes 19 other similar projects across the city. The project is currently in the construction phase and is expected to be completed by the end of 2024, modernizing Brightmoor’s stormwater infrastructure and providing long-term environmental and community benefits.
(Ref.1-3)

The beach of Vétiver, located in the municipality of Case-Pilote, is one of the most important nesting sites for the critically endangered hawksbill turtle (Eretmochelys imbricata) in Martinique. It is also a nesting ground for the green sea turtle (Chelonia mydas), another endangered species. As one of the last minimally urbanized beaches in the North Caribbean of Martinique, the site plays a vital role in the conservation of these species. In addition, fishing restrictions in the area significantly reduce the risk of turtle mortality caused by accidental capture in fishing gear, which is the leading cause of human-related sea turtle deaths in the Antilles.
However, the site faces several stressors that hinder successful nesting. The surrounding vegetation is severely degraded due to invasive alien species, and much of the shrub and tree cover has disappeared from the backshore, where turtles prefer to nest. Without adequate vegetation, hatchlings are left exposed to the heat. Additionally, the beach is frequently disturbed by local residents and visitors for recreational activities. With no designated parking area, cars often park directly on the beach, compacting the soil and further limiting the chances for vegetation to recover or turtles to dig nests. This compaction forces turtles to lay their eggs closer to the shoreline, increasing the risk of nests being washed away by heavy swells.
In 2022, the non-profit organization "Asso-mer" and its partners launched the Véti’Vert project on a previously neglected public green space. Through environmental restoration efforts, they created a nesting enclosure on the backshore to mitigate these stressors and improve the conditions for sea turtle nesting. The project also engaged with local residents to increase the chances of success (Refs 1-3).

The Fairy Garden, also known as the WOW Recreational Park, is a distinctive green space located near Diósgyőr Castle in Miskolc, Hungary. Since its opening in April 2020, the park has quickly gained popularity, earning third place in the 2020 Tourism Attraction of the Year award in the professional category. Once a neglected and polluted site with historical significance, the area was transformed by a local entrepreneur. After removing over sixty containers of waste, including hazardous materials, a park was created that harmonizes with the natural environment, preserving existing willow trees and integrating water features fed by local streams. When creating the park, the creators respected the plants of the area to the maximum, not a single tree was cut down, and the fruit trees were also kept.
The park boasts various decorative elements, including a carousel, a garden cinema, and other amenities. However, in September 2021, it was closed indefinitely for renovations. Gábor Vaszil, the lessee who had rented the land from the Miskolc municipality, intended to purchase the property for further development. Despite initial support from the local government, the transaction was halted due to concerns raised by the regional Water Management and Protection Authority regarding the protection of Miskolc's drinking water resources. Their ongoing investigation has delayed any further decisions about the sale or the future of the park. In the meantime, the garden remains open to the public for leisurely walks, similar to other municipal parks in Miskolc.
(Ref.1-4)

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).