Green Spaces

By Effie Jia

Introduction

Green space: an area of grass, trees, or other vegetation set apart for recreational or aesthetic purpose in an otherwise urban environment. In recent years, architects and designers have become especially innovative and efficient by reclaiming abandoned infrastructure and turning it into green spaces. Such solutions include green walls, green roofs, pocket-parks, and more. Green walls are partially or completely covered walls with greenery that includes a growing medium such as soil.¹ Green roofs are partially or completely covered with vegetation and a growing medium planted over a waterproof membrane.² Pocket-parks are small parks frequently created on vacant building lots or small, irregular pieces of land that are accessible to the general public.³

Green spaces provide environmental, psychological, societal, and economic benefits to the communities that they are implemented in.⁴ However, a problem faced by green space is the constraint of land, which limits a city’s ability to allocate huge areas of open land for parks or other forms of green space. Nonetheless, there are several solutions to taking advantage of the space that is available in order to design a system of coherent, beneficial green spaces.

Green spaces provide benefits in three main problem areas:

The Environment

Green spaces help maintain biodiversity, regulate urban climate, and control noise and air pollution. Green spaces in a predominantly urban area act as reproduction centers for plants and animals. Soil and air quality also improves because of green spaces because they provide a link to the natural world and its cycles.⁵ Good examples of this include Forest Park in Portland, Oregon, which is a public municipal park, and the Chicago Wilderness, which is a regional system of nature reserves and protected land.⁶ Forest Park plays a major role in the quality of life for Portland’s metro-area residents. It contributes to clean air and water and is home to more than 150 plant and animal species.⁷ The Chicago Wilderness has a similar impact, with focus areas in maintaining ecosystems, protecting species, addressing regional water issues, and engaging landowners in conservation.⁸

Economics

Since plants improve circulation and provide shade, green spaces help lower the temperature of buildings and subsequently reduce the energy cost associated with the cooling of buildings.⁵ They can also be used to reduce public costs for stormwater management, flood control, transportation, and other forms of built infrastructure.⁶ For example, it is estimated that the “187,767 acres of tree canopy in the Washington, D.C. metropolitan region provides 949 million cubic feet in avoided storage of water, valued at $4.7 billion annually”.⁶ The canopy does this by slowing the flow of stormwater, absorbing water, and increasing groundwater discharge.⁶

Health

Green spaces also improve human health through social, psychological, and physical benefits. They provide recreational space and a place to experience nature as well as opportunities for people to interact and connect with each other. The creation of a public gathering place, such as a park or green space, allows a community a common area to socialize and bond. Spending time in nature also relieves mental fatigue and feelings of violence and aggression, thereby restoring well-being and promoting social development (especially in children). For physical health, green spaces have been shown to lower blood pressure and cholesterol levels. They also contribute to positive progress in developmental issues (especially in behavioral disorders like ADHD).⁵ These psychological benefits of green spaces could potentially help reduce community disruptions and criminal behavior.

Solutions

1) Create an interconnected system of parks and open space

A major issue that green spaces address is the sense of community, or rather the lack thereof. By interconnecting parks and open space, people and neighborhoods will be better connected as well. A system of parks is “manifestly more beneficial”⁶ than parks created in isolation because it allows for social development and community-oriented progress. When parks are joined by trails, greenways, and cycleways, the interconnected system provides healthier recreation and transportation.⁹ These spaces provide opportunities for recreational activities and for people to interact and connect with common interests.⁵ Meanwhile, if a park is isolated, the potential for community interaction is hindered.

The main benefit to creating a system of parks rather than a megapark (a park that is typically thousands of acres large) is accessibility.¹⁰ In order to maximize utility, planners should aim to place the majority of parks near the center of a neighborhood and within a five-minute walking distance for most people.⁵ Furthermore, parks increase the standard of living for the inhabitants of a neighborhood and they also promote healthier lifestyles.¹¹ Another benefit to constructing multiple, smaller parks instead of megaparks is that they are better at preventing gentrification, which is when those who live in a neighborhood are forced to leave because of increased land values.¹²

Inherently, the construction of parks requires the consumption of land space. A common standard for allocating land for recreational and green space is 10 acres per 1000 people.¹³ In comparison, pocket-parks are typically less than 5 acres per 500 to 1000 people,¹⁴ which results in a more efficient use of space. Furthermore, pocket-parks often try to meet a variety of needs (i.e. play structures, social gathering areas, etc.) despite their size, so they do a good job of optimizing space with function. However, due to their limited size, pocket-parks do not meet all the needs that standard parks can provide for. For example, neighborhood parks may have facilities like tennis and basketball courts, while pocket-parks are generally used as play areas for children or as passive, aesthetic areas.¹⁴ Thus, if space is extremely limited in a city, pocket-parks might be a good alternative to standard parks.

When acquiring land for parks and green space, Portland, Oregon does a good job of outlining seven acquisition strategies, which are shown in Figure 1.

Figure 1: Portland, Oregon’s acquisition strategies.¹⁵

A good priority to keep in mind when acquiring land for parks is the degree of connectivity and usability the property offers.¹⁵ For funding, park land could be acquired through capital improvement (adapting or improving an already existing property), grants, mandatory dedication (a condition for certain administrative actions that require a developer to dedicate property to a government),¹⁶ and surplus property programs (excess land that exceed departmental needs).^17,18

Typically, neighborhood parks and recreational space take 1 to 4 years for construction. Depending on what facilities are included (i.e. baseball fields, play structures, tennis courts, etc.), neighborhood parks tend to cost $50,000-70,000 to build and annual maintenance costs range from $18,000-22,000.¹⁷

2) Redesign existing infrastructure into green spaces

“We need to think about land as a three-dimensional object. We can put things on sides of buildings, on top of buildings. If we have open land at ground level, how does it reduce heat and manage stormwater? How can it enhance diversity, provide for pollinators, produce food?” —Morgan Grove¹⁹

A rising problem in cities is the lack of room for parks. However, there are multiple innovative solutions to integrating green spaces into cities despite the limiting amount of space. These solutions include green walls, green roofs, pocket-parks, former industrial sites, and abandoned infrastructure.⁵ Some great examples of redesigning land and infrastructure into green spaces are Seoul’s Cheonggyecheon stream restoration project in Korea, San Francisco’s parklets in the United States, Hangzhou’s park-making on “wasteland” in China, New York’s High Line in the United States, and Aguascalientes’ La Línea Verde in Mexico.²⁰ All of these places have one major theme in common: the repurposing of infrastructure into green space.

The Cheonggyecheon project (Figure 2) took a traffic-choked freeway and turned it into a stream corridor (an area of land that drains water, sediment, and dissolved materials to a common outlet)²¹ that attracts 60,000 visitors daily.²² Originally, the Cheonggyecheon was a stream that had degraded into an open sewer, and, due to sanitation reasons, was paved over into a freeway. The project’s main benefits include “a significant increase in overall biodiversity, a reduction in the urban heat island effect and air pollution, improvement in public transit ridership and the downtown quality of life, and greater economic development in the surrounding area”.²²

Figure 2: Cheonggyecheon stream restoration project, Seoul, South Korea. Source: Wikimedia Commons

New York’s High Line (Figure 3) is another great example of redesigning infrastructure. The High Line was originally an out-of-use railroad trestle and was turned into a public landscape. Piet Oudolf, the planting designer of the project, selected native, drought-tolerant, and low-maintenance species in order to reduce the amount of resources that go into the landscape. By catering to the landscape’s natural microclimates, the project is able to cut down on water and other resources.²³

Figure 3: High Line, New York, USA. Source: Wikimedia Commons

La Línea Verde (Figure 4), located in Aguascalientes, Mexico, is an oil pipeline easement converted into a 12-kilometer long linear park. The project greatly changed the social landscape in neighborhoods near and next to the park. Before its redesign, the abandoned fields were littered with garbage and acted as a haven for criminals. After the project, robberies and assaults were estimated to have declined by more than 50 percent. Now, the park is typically busy with “families out walking, biking, or exercising, or just gathering in the park’s many social spaces”.²⁴ La Línea Verde is a symbol for the positive societal changes that green spaces can produce. Green spaces like this provide opportunities for social development and community-oriented behavior.

Figure 4: La Línea Verde, Aguascalientes, Mexico. Source: Wikimedia Commons

However, one major impact of green space is gentrification. Although green spaces can make neighborhoods healthier and more aesthetically attractive, this can result in an increase in housing costs and property values. Ultimately, this leads to gentrification and a displacement of the residents for whom the project was designed to benefit.²⁵ One way to reduce gentrification is to build smaller, interconnected parks, like previously stated in Solution 1. Some other methods to combat gentrification is to stabilize existing renters, control land for community development, build income and assets creation, and develop financing strategies.²⁶

The timespans for these projects vary significantly, ranging from 2 years (Cheonggyecheon stream restoration project) to 10 years (New York High Line). Likewise, the cost also varies. However, projects tend to have public or governmental funding, which can help reduce costs. This kind of funding is not always a certainty, but greatly aids in the implementation of a project. For example, $44 million of $152 million were raised by Friends of the High Line, the group that led the project.²⁷ As for La Línea Verde, which was a $40 million project, the National Federation of Sports gave the municipality $10 million and the National Ministry for Communications and Transport granted $7.5 million.²⁴

Conclusion

Ultimately, green spaces are a great resource to improve an urban setting due to their plethora of benefits in several different aspects of society, ranging from environmental benefits to social benefits all the way to economic benefits for the city as a whole. These impacts can change the urban landscape and push communities to lead healthier lives and to communicate and interact more with each other. By prioritizing the interconnectedness of parks and green spaces, city planners can promote community-oriented behavior and exercise. Green spaces also help cities reduce costs of services (i.e. stormwater collection, air conditioning, flood control, transportation) and maintain biodiversity. By designing a city that balances the construction of green spaces in the form of parks as well as more innovative solutions like parklets and green roofs, a community can optimize the potential benefits that green spaces provide. Projects like the High Line and La Línea Verde may be costly, but with the help of public and government support, these parks can improve the quality of living for all those who live nearby. Going forward, a good strategy would be taking unused space (i.e. abandoned infrastructure) or unconventional space (i.e. building walls and roofs, parklets) and converting them into green space.