Tree-lined streets in a city neighborhood. Urban nature preserves and community farms. Creeks winding through developed areas, their riparian corridors providing habitat and connectivity for wildlife large and small. These are just a few examples of urban green space – a critically important tool for climate resilience, biodiversity, and the physical and mental health of our communities. And yet, urban green space is rapidly disappearing from our cities, a loss felt most severely in low-income communities and communities of color, but affecting everyone. In partnership with community leaders, Green Foothills is working hard to expand urban green space in all its forms, so that everyone can experience nature close to home.

Why Urban Green Space Is Critical

In an era of warming temperatures, green space close to where people live and work provides an irreplaceable benefit in reducing the urban heat island effect caused by pavement, buildings, and other surfaces that absorb and retain heat. Studies show that temperatures can be noticeably hotter where there are fewer trees and other greenery – an effect that is strongest in low-income communities of color, which generally have fewer street trees, smaller front and backyards, and fewer neighborhood parks.

Parks build community, provide recreational opportunities, and improve physical and mental health. A neighborhood park is often the social center of a community – the place where family gatherings happen, where birthdays and special events are celebrated, and where friendships among neighbors are formed and strengthened.

Urban green space reduces air pollution – a significant problem for asthma sufferers everywhere, but especially in many low-income urban communities, where asthma rates are disproportionately high. Additionally, research has shown that just being in nature is good for your health. People need to experience nature in order to be mentally and physically healthy, and for that, we need green space.

Another benefit is that green space filters pollutants from rainwater, prevents erosion, and replenishes groundwater. When we decrease the area that is covered with impervious surfaces like pavement, more rain is absorbed into the ground, preventing flooding.

Urban green space is also important as wildlife habitat. There is sometimes a tacit assumption that wildlife cannot thrive in urban areas, but landscaping parks and home gardens with native plants leads to vastly increased diversity of insects and birds, which in turn leads to greater diversity throughout the food chain. Creeks through urban areas with healthy riparian forests along their banks are especially important for wildlife, because they serve as migration corridors as well as live-in habitat, providing lifelines of survival for many species. We are in the midst of not just a climate crisis, but a biodiversity crisis, with between one-third and one-half of all species at risk of extinction by the end of the century. We must create wildlife habitat wherever we can, including in urban areas.

Green Space Must Accompany Increased Urban Density

Despite knowing all the benefits of urban green space, cities in San Mateo and Santa Clara Counties are rapidly losing trees and greenery due to increased development density. When we densify, even through redevelopment of already-developed parcels, it nearly always involves removal of trees and greenery. And as we add more residents and workers, we are not ensuring a corresponding increase in the amount of parkland that’s available for people to enjoy.

To be clear, we need dense infill development in order to provide housing for all income levels close to transit corridors and job centers. We need more housing, and our infill areas are the right location for it. But this new infill development must be accompanied by new urban green space, or the result will be increased inequity, loss of biodiversity, and worsened health and quality of life for everyone.

How to Make Urban Areas Greener

Fortunately, there are a variety of ways in which we can increase urban green space:

• Create more nature in urban areas. While all types of parks provide important recreational and community benefits, we should prioritize urban nature preserves, and natural landscapes within urban parks. Preserves such as Ulistac Natural Area in the City of Santa Clara (a 40-acre former golf course along the Guadalupe River, now restored to native habitat) provide an oasis of green in the midst of developed areas, allowing residents a chance for peaceful, restorative experiences near their homes and jobs. Even parks that are primarily playgrounds and soccer fields can incorporate native plantings, such as pollinator gardens to support local populations of birds and insects.
• Protect the urban tree canopy. Trees are one of the most important types of urban vegetation. They filter air and water pollution, absorb carbon, and reduce the urban heat island effect by shading buildings and streets. We should encourage native species of trees wherever possible. They provide the best habitat for native wildlife as well as conserving water, since native trees typically have lower water requirements than non-native species. Robust public tree-planting and maintenance programs help support the canopy of street trees. Tree protection ordinances prevent unnecessary tree loss on private property, especially larger heritage trees.
• Establish riparian corridor setbacks. In some urban areas, creeks are the only remaining native landscape for local species, the majority of which rely on riparian habitat for foraging, breeding, nesting, and migration. Riparian corridor setbacks protect both people and wildlife. By preventing development from encroaching on the creek corridor, we prevent erosion that results in bank collapse as well as giving riparian vegetation space to grow.
• Support community farms and gardens. Urban farms and community gardens are not just a way to grow vegetables; they also bring people together. Residential gardens can help a community become more food resilient and connect people to the soil and to the act of nurturing plants and watching them grow.
• Fill the unnoticed edges with green. With land values soaring, finding significant acreage for new city parks is both challenging and expensive. But we don’t need every green space to be big. Green roofs, bioswales, and rain gardens in public rights-of-way take little space. Encouraging native plant palettes in development guidelines and in designs for public spaces takes none. Great examples of this include Google’s plans for its new campuses in Mountain View and the Diridon neighborhood of San Jose. Their site designs include removing pavement to create new natural areas, pulling development back from creek corridors to restore the riparian habitat, and planting butterfly gardens and creating thriving wetlands instead of landscaping with the standard non-native species. Other developers should follow this model, and cities should include similar ideas in their design guidelines.

What Green Foothills Is Doing

Green Foothills has advocated for urban green space throughout the years. In 2016, we worked with the City of Santa Clara to address the city’s parkland shortage by enacting a parks impact fee ordinance, by requiring the massive CityPlace development to include a 35-acre park, and by passing a ballot measure mandating that any sale or development of a city park must be approved by the voters. In 2018, we partnered with the SPHERE Institute on a successful year-long campaign to persuade the State of California to turn an undeveloped parcel on the Bay in Burlingame into a shoreline nature park that will include a newly created tidal marsh. And in June 2022, we joined with multiple partners to urge the City of Palo Alto to strengthen its tree-protection ordinance for the first time in 20 years.

We are currently addressing the problem of insufficient urban green space in San Jose, especially in historically marginalized neighborhoods. Our team is working with community members on opportunities for new urban green space in San Jose, particularly on the parks-poor East Side. The Reid-Hillview Airport site and the former Pleasant Hills Golf Course present two such opportunities for new parks and green space.

In East Palo Alto, we are partnering with community members to ensure that a massive office development planned for the Ravenswood neighborhood includes significant new urban green space, preserves meaningful access for residents to the existing Bayfront open space, and protects wetland habitat and species.

Everyone Deserves Nature Close to Home

It’s easy to think of open space and nature as something that only exists outside of cities. But the reality is that we need to incorporate nature into our urban areas, not only to combat climate change and promote biodiversity, but also because access to green space is an equity issue. Green Foothills will continue advocating for increased urban green space in all our communities so that everyone can have access to nature close to home.

An earlier version of this article appeared in Green Foothills’ Summer 2022 printed newsletter.