The Brookings Institution recently released a comprehensive report on metropolitan demographic changes over the past thirty years, which highlighted the increasing concentration of the U.S. population in major metropolitan areas.  Overall, metropolitan areas have grown consistently since 1980, and now over 80% of Americans live in metropolitan areas, i.e. cities and their suburbs.  Though suburban growth outpaced city growth between 2000 and 2010, all of the five fastest-growing metropolitan areas saw higher percentage growth in their urban cores.

Forecasts suggest cities will continue to grow over the next several decades, as empty-nesting baby-boomers retire to cities and the Millennials, who are known to prefer urban living, move into their first homes.

All of this is good news for city parks.  As American cities continue to grow, so will the demand for high-quality parkland accessible to urban neighborhoods.  Density creates park demand, and parks attract density.  Perhaps for these reasons, notable downtown residential growth in recent years has occurred in tandem with major investments in urban parks, from Cincinnati to Denver to Houston.

Central Park, New York
Credit: NYC.gov

While there are certain park functions for which density creates challenges, such as habitat preservation, park environments are largely improved by dense and diverse activity and use.  Urban observer and advocate Jane Jacobs was the first to suggest that parks are vacant spaces enlivened by the presence of urban activity.  Over the subsequent decades, the broader community of urbanists has continued to pursue this axiom, as well as its counterpart, that density requires the presence of open space. In his recent book, Walking Home, Ken Greenberg writes:

Greater density paradoxically goes hand in hand with the preservation of nature, giving urban dwellers easier access to the natural world than is the case for their suburban counterparts. Great urban parks like Central Park and Prospect Park in New York, the Bois de Boulogne in Paris, Chapultepec Park in Mexico City, and the Toronto Islands have historically been possible because of the larger populations nearby that have built and maintained them.

In addition to creating demand for parks, density also provides opportunities for parks to sustain themselves financially.  Park advocates and philanthropists, many of whom live or work near their parks, support park-friendly policies and contribute funding and volunteer hours. Dense activity also provides a market for fee-based park programs, from concessions to special events to carousels and skating rinks. These program elements in turn contribute to parks' success, providing community amenities and reasons to travel to and linger in public space.

Residential density and open space have proved mutually supportive over time. Central Park and the growth of Manhattan are perhaps the best-known example of this trend.  Developed in the 1860s when the population of New York City was almost entirely concentrated downtown, the Central Park was located in public land (acquired through eminent domain) in a 3 by 47 block section of the City's newly laid out grid.

The park's designer, Frederick Law Olmsted, suggested that the residential development Central Park would attract would create enormous economic value to the city, creating a rationale for public investment. According to The Greatest Grid: The Master Plan of Manhattan 1811-2011:

Despite the lack of uptown residents, Olmsted anticipated that when the street grid eventually filled out, property near the park would increase in value, and he defended the park's size on these grounds. When the construction of the grid was complete, Olmsted expected that an 'artificial wall, twice as high as the Great Wall of China, composed of urban buildings' would circle the park…

More recently, Santa Fe Railyard Park and Plaza was created in response to demand from the community to preserve the historic railyard site near the downtown core. Between 2000 and 2010, Santa Fe's population grew by 8%, and this growth increased demand for open spaces for recreation and public gathering.

The Master Planning process for the site, which involved over 6,000 members of the local community, preserved 12 of the site's 50 acres as a destination downtown park with an immensely popular farmers' market. The remainder of the site was divided between cultural and community uses, commercial art galleries, office space, retail and restaurant venues, live-work units, and purely residential units. This vibrant mix of uses generates diverse activity and creates a natural constituency to support the new park.

Note: The Greatest Grid exhibit is on view at the Museum of the City of New York through July, 2012