Arid (Desert, Steppe)

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)

Eliseo Collazos is located in the coastal desert ecosystem of the Lomas or ‘fog oasis’, an area that receives less than 10 mm of rainfall per year. Vegetation cover is of particular importance in the hills surrounding Lima, as it provides critical solutions to erosion, landslides and soil degradation in the ecologically degraded ecosystem of the Lomas. However, this ecosystem is facing risks from urbanisation, illegal mining and agricultural practices, resulting in the lack of the delicate mist-fed greenery for which the Lomas are known (2). This has led to increased particulate matter in the air due to exposure to sand and wind, aggravating respiratory diseases such as tuberculosis, which is prevalent in Lima's informal communities (2).
Low-income communities have inhabited this area, forced to migrate from the rainforest, highlands and city to the desert slums (4), who have only been able to settle in these landscapes with little access to resources, prone to disaster risk, little public investment in infrastructure and little access to green spaces (2). As a result, these communities live in poor conditions (1). For this reason, in 2013, the University of Washington, under its Urban Informal Communities Initiative programme (1), initiated a participatory project that sought to address the challenges faced by the inhabitants of this area (1, 2). In a series of participatory workshops, residents identified greenspace and food security as top priorities in their community; the Gardens, Greenspace and Health project responds to these priorities as an initial step towards the expansion of greenspace, agriculture and ecological restoration in and around the Eliseo Collazos community (2, 4).
Although individual families constructed them, the front yard gardens contribute to a shared public realm and community greening (4). The general project also involved the installation of fog catchers and the creation of common recreational spaces (4).

In Phoenix, many residents live in dead zones with little or no access to fresh food. These zones are called 'food deserts,' which represent a low-income area with low access to a grocery store (3). Out of the 43 food deserts identified by the city, 18 are fully or partly in south Phoenix (2-3). In 2017, Two researchers from Arizona State University’s School of Sustainability and Leuphana University Lüneburg in Germany began exploring the idea of creating a sustainable food forest cooperative in Phoenix to provide fresh, healthy food, supporting local entrepreneurs, and promote environmental sustainability (1). The project's development team spent months immersing themselves in the world of food forests, by exploring different types of community gardens, discussing preferred characteristics, anticipating local challenges, and identifying potential collaborators (1). As a result, The Food Forest Cooperative was established and planted roots in a 0.5 acre (0.20 ha) plot within the Spaces of Opportunity Community Garden in 2022 (1). This food forest engages the local community by offering educational opportunities around the value of culturally relevant, whole fruits and vegetables, medicine making, and learning about the many uses of edible/medicinal plants (4). The Food Forest Cooperative as a multi-generational project that members preserve for their children, and their children’s children (2). The intention behind the project is to address food insecurity in south Phoenix and empowering the community to take ownership of it and reconnect with their ancestors through the land and food (2). Through the Cooperative, members can contribute different skills, from administrative work to manual labor to community education and traditional medicine (2). It was created to empower community members and challenge the patterns of our food system through the blending of environmental, social and economic goals (4).

Minimizing heat stress is a critical priority for Phoenix, the hottest major city in the U.S., where heat-related deaths reached at least 359 across Maricopa County last year. The city's expansive urban layout and infrastructure exacerbate the urban heat island effect, making an already scorching climate even more hazardous. In addition, heat impacts communities unequally, with some neighborhoods up to 10 degrees hotter than others. Lower-income and predominantly Hispanic neighborhoods often have less canopy cover and fewer resources to combat rising temperatures, making them more vulnerable to extreme heat.
To address this, the City of Phoenix launched the Cool Corridors Program in 2020, a key initiative in its broader climate resilience strategy. This program, a partnership with American Forests and the Phoenix Street Transportation Department, aims to establish a network of shaded pathways that connect communities across the city. These corridors enable residents to travel safely to schools, public transit, and other city hubs, promoting environmental sustainability and public health.
The program prioritizes investment in low-income, heat-sensitive neighborhoods to improve tree equity and create green spaces where they’re most needed. The first Cool Corridor was developed in 2022 at Cesar Chavez Park, where over 250 trees were planted with the support of more than 100 volunteers, setting a strong example for future initiatives. By 2030, Phoenix plans to complete 100 Cool Corridors citywide, building a more resilient and livable urban environment for all residents. (1-5, 7-8, 10)

Over the past 10 years, Lima's population has grown from 8.2 to 9.6 million people. As the city's urban sprawl and population density have increased, green spaces have been replaced by grey infrastructure. Consequently, it has become challenging to ensure that residents enjoy a good quality of life (1, 2, 3). In December 2019, Lima City Hall launched "Limeños al Bicentenario," an initiative to revitalise the city's public spaces (1, 3). This program seeks to transform public areas through low-cost interventions, based on criteria such as vulnerability, citizen participation, and catalytic potential, among others (3). It also aims to foster social cohesion by involving residents in the maintenance of these newly renovated areas, while improving the city's resilience to climate change (1, 2, 3). Since its inception, the project has reclaimed 17 public spaces, covering an area of 41,000 m² (3). 430 trees have been planted, and the project has benefited from the collaboration of civil society and private sector partners (3). The programme also focuses on addressing climate change. Heat waves, droughts, floods and mass migration are the main climate-related risks affecting the city. In particular, the expansion of grey infrastructure at the expense of green spaces has exacerbated the risk of heat waves, causing temperatures to rise by up to 3.5 °C in certain areas of Lima (3).
One of the projects involved the recovery of public spaces in Teniente Pavia. For many years, the space was used as a public parking lot, and at night it accumulated garbage, there was alcohol consumption, drug use, and other problematic issues. There was no vegetation, benches or infrastructure for recreation. The neighbours, especially children, did not have access to green areas or recreational spaces (5). For this reason, in 2020 the project was initiated to repair sidewalks, plant vegetation, create gardens, and install infrastructure for play, rest, and exercise (3, 4).

The Praderas de Vida garden is an initiative to transform a former rubbish dump into a source of employment and empowerment for the residents of the Praderas de San Juan de Miraflores Human Settlement (1). This agroecological community garden was developed as part of ISA REP's Sustainable Easements programme (13), located in the easement area of Peru's energy network, and it has collaboration efforts with KUNAN, Misha Rastrera, and La Muyita, brings together twelve female heads of households who cultivate, harvest, and process a variety of medicinal plants that have aromatic, antiseptic, and relaxing properties (2, 3).
Beyond agricultural production, the garden has become a hub for emotional and economic support, fostering a connection with nature through plant care and interaction with the local ecosystem (3). It has also led to the establishment of a social enterprise, "Praderas de Vida," allowing women to participate in agroecological fairs to market the products derived from the medicinal plants grown in the garden (3).
The garden has evolved into a space for learning and community collaboration, promoting the importance of sustainability and biodiversity conservation (6).

Phoenix is one of the hottest cities in the United States, with temperatures regularly exceeding 40°C (104°F) for more than 90 days each year. The urban heat island effect is severe here, posing a significant health risk. Many communities in Phoenix lack equal access to shade cover—often, the impact of extreme heat disproportionately affects low-income neighborhoods that lack resources for tree planting and maintenance. In contrast, wealthier areas tend to have more trees and are visibly greener, which helps reduce the heat residents experience.
To address these disparities, the City of Phoenix partnered with SRP, a not-for-profit public power utility, to launch the "Right Tree, Right Place" program in 2018. This initiative aims to bring shade relief to areas most in need, such as parks, public transit stops, and schools, while replacing older trees that interfere with SRP power lines. SRP and the city work together to identify trees that pose risks to overhead power lines, and for each tree removed, three new trees are planted—either in a different location or with a species better suited to coexist with power lines.
One of the program’s notable projects took place in West Phoenix’s Cortez Park, where 24 drought-tolerant trees from four different species were planted. This diversity helps protect the trees against pests and other natural threats, ensuring their longevity and resilience. Through initiatives like these, the "Right Tree, Right Place" program contributes to Phoenix’s larger goal of developing a robust, biodiverse urban forest. By expanding green infrastructure, the city aims to reduce local temperatures, improve air quality, and create cooler, healthier neighborhoods for all residents. (1-8)

The intervention of the Ecological Park of La Molina is an urban-landscape design project developed between the San Martín de Porres University, through the IVUC, the Institute of Housing, Urban Planning and Construction, and the Municipality of La Molina (7). This is the first ecological park in the city of Lima, located in a characteristic ecosystem such as Las Lomas, between 600-1000 m.a.s.l. (1). It is a natural area that is part of the hill system of Villa María del Triunfo, located in the Subtropical Coastal Desert ecoregion, and is part of the Regional Conservation Area ‘Sistema de Lomas de Lima’ (7). The City Council decided to open this space in 2022 to the public, as a 200-hectare area, designed to bring people closer to nature, through outdoor activities and environmental education about its fauna, flora and microclimates (1). Thus, citizens can enjoy a recreational area with multi-purpose spaces and sports circuits; a cultural area where workshops and an open-air amphitheatre are held; an ecological interpretation area with exhibition galleries and an interpretative route; and an administrative and control area (1). The park also envisages reforestation efforts in areas that are currently arid and infertile to convert them into green areas for the enjoyment of citizens (1). In 2023, conservation efforts were reinforced for an additional 50 hectares, due to the danger posed by encroachment and land trafficking (4).

Over the past two decades, as Phoenix’s population has surged since the 1990s, large expanses of farmland have been paved over to make way for urban development. This transformation has increasingly disconnected the city from its agricultural roots. In 2000, Janna Anderson recognized a growing need for local farms to strengthen their ties with the community and for increased access to fresh, locally sourced produce. With a vision to reconnect the community with its agricultural heritage, she purchased a historic orchard property in southern Phoenix, near South Mountain, in 2011. The property, which included a 1918 adobe home, was transformed into a thriving mixed-fruit orchard.
At Pinnacle Farms, Janna planted over 1,200 trees, including peaches, apricots, and rare Maktoom Dates, which were brought to the U.S. from Iraq in 1910. These heritage crops have unique flavors and textures not commonly found in grocery stores. In 2015, the farm became certified organic, underscoring Janna’s commitment to sustainable farming practices. Her focus is on cultivating varieties that are uniquely suited to the arid Southwest climate, using methods that conserve water and promote soil health.
Janna’s approach to farming also highlights the potential of heritage varieties to support food security in the desert. By growing these rare and resilient crops, she not only preserves biodiversity but also brings attention to how such practices can contribute to a more sustainable, local food system. Pinnacle Farms serves as a living reminder of Phoenix’s agricultural history, a place where fertile soil and sustainable farming practices continue to thrive. The farm embodies the deep agricultural roots of the region, connecting Phoenix’s past to its future and proving that the city’s rich farming tradition is far from lost. (1, 2, 6, 8)

San Borja has 1,347,000 square metres of green areas, equivalent to 12 square metres of green space per inhabitant, one of the highest ratios in the capital (1, 2). In total, there are 75 parks within its jurisdiction (1, 3). However, in recent years it has consolidated its role as a metropolitan urban centre and has become denser with new multi-family construction projects replacing traditional single-family homes with gardens (2). As a result, tree cover has decreased, affecting the creation of shaded areas and air quality, putting the health of residents at risk (2). Nevertheless, this municipality has reaffirmed its participation in the Global Covenant of Mayors for Climate and Energy, committing to implement policies and take measures to reduce (or limit where appropriate) greenhouse gas emissions and prepare for the impacts of climate change, as it is vulnerable to heat waves and droughts, as well as high wind and thunderstorm hazards and fires (1). Thus, since 2014, 56,000 trees have been planted, which is one tree for every two residents in the district (2). The mitigation programme includes 40 measures, including the creation and conservation of green areas, which involve planting trees to create urban forests to help regulate temperature, prevent heat waves, improve CO2 absorption, and preserve endemic species (1). In addition, the programme promotes the use of organic farming practices and the propagation of plants using natural methods (1).
One of the sectors where there has been the most progress is Sector 12, with 31% of the green areas created (3). Within this sector, the district is planting and creating an urban forest within the premises of the Army Headquarters, better known as ‘Pentagonito’. Its objective is to educate neighbours and promote greater environmental awareness (3, 4, 5).