Maintaining the common grounds

    Cities need green spaces to maintain the well-being of their citizens. But is the realization of their value making them more private luxury than public commons?

    When the mayor of London, Sadiq Khan, cancelled the ‘Garden Bridge’ earlier this year, it was a controversial end to an already controversial project. The more than 300 m, pedestrian-only crossing over the River Thames would have created a distinctive green space attracting millions of visitors a year. However, despite support from former mayor Boris Johnson and others, the project aroused significant opposition on multiple grounds.

    The estimated cost of the bridge ballooned, and landings would have sacrificed existing green space including mature trees, some planted as a memorial to London’s fallen soldiers. But perhaps the biggest source of outcry was that the bridge would have been rented out for private functions on numerous days throughout the year,  along with permanent restrictions on who could access the bridge, when, and for what purpose.

    Such ‘pseudo-public’ spaces are not uncommon in London. Seemingly public squares, parks and gardens are actually owned or operated by private companies who can impose rules on the types of activities permitted in those spaces and use private security to enforce them. A lush forest crossing a river would have been visually striking and a unique feature cementing London’s status for visitors around the world, but bridges are meant to connect people and places, while public spaces serve as a forum for uses that can both comfort and challenge society. The Garden Bridge failed on both counts.

    The conflict between urban gentrification and who benefits from green spaces in a city is growing. In 2014, a real estate agent used a community garden in Oakland, California, to promote historically African American neighbourhoods to young, professional, and largely white home-buyers (, raising fears that rents and housing prices would soar, sparking mass displacement, as prospective buyers rushed to be close to such ‘amenities’. Residents and activists in Washington D.C. have found themselves resisting projects to plant trees and beautify neighbourhoods, for fear that this will trigger an influx of richer residents, forcing out those already living there (;

    Perhaps no example of urban green space is more famous than New York City’s High Line, which repurposed train tracks along the West Side of Manhattan into an elevated park. It has ignited not only a rush of new real estate development along the High Line’s path, but also led other cities to try to copy the idea. However, the success of the High Line has not been shared by everybody in the area. Residents and businesses have had to leave due to higher rents commanded by owners and developers wanting to take advantage of the five million visitors every year and the rare proximity of greenery in Manhattan (

    The battle over who benefits from parks and gardens has become a major topic of research. In a recent book, leading environmental sociologists Kenneth Gould and Tammy Lewis1 examine urban projects through the lens of environmental justice, sketching out the trade-offs and implications for both existing and new residents as cities struggle to meet competing needs with existing resources. This may feel like a ‘first-world problem’, but much of the world's urban growth is occuring in developing countries. World Bank statistics show the global rural population remaining relatively constant at a little over 3 billion, whilst the urban population continues to grow at an accelerating rate, passing the rural numbers in 2008. A 2015 systematic review of studies into the effects of access to green spaces on a population’s health2 consistently saw benefits accruing through improved air quality, increased physical activity, reductions in stress levels and greater social cohesion.

    Urban green spaces are not confined to parks and recreational land. Urban agriculture and gardening are powerful tools in ensuring that everyone has access to a healthy diet. ‘Food deserts’, areas without ready access to retailers of fresh fruit and vegetables, are proliferating in cities across the planet. Community gardens and allotments can provide a grass-roots approach to supplying such essentials, providing both greenery and a place for people to come together.

    There is wide political support for such activities. During the recent British general election, Labour Party leader Jeremy Corbyn vowed to continue tending his North London allotment if he was elected Prime Minister in a nod to the symbolic power of such spaces in increasingly crowded and grey cities. In 2016, the US Senator for Michigan, Debbie Stabenow, introduced an Urban Agriculture Act for states to help “urban farmers get started or expand their business, so they can sell more products and supply more healthy food for their neighbors”. Michigan includes Detroit, a city that has lost a quarter of its population over the past two decades and experienced an embarrassing bankruptcy, but which is now dotted with community gardens in minority neighbourhoods to help residents overcome the deprivations of food poverty.

    None of this is new. In 1898, Ebenezer Howard founded the Garden City Association, to facilitate the creation of a series of ‘garden cities’ throughout England; self-contained communities balancing housing, industry and agriculture. The desirability of the first of these, Letchworth, pushed house prices beyond the reach of working-class families, making it gentrified even before it was completed.

    Trying to keep cities and their neighbourhoods from changing is a quixotic endeavour. Preventing new residents from coming into a neighbourhood raises the same conundrums as trying to block trees from being planted along a street. Community gardens and parks provide the most benefit when community is defined in its broadest sense. Perhaps the key is to stop thinking of such places as an amenity and consider them a trust held in common.


    1. 1

      Gould, K. A. & Lewis, T. L. Green Gentrification: Urban Sustainability and the Struggle for Environmental Justice (Routledge, Oxford, 2016).

    2. 2.

      D’Alessandro, D. et al. Epidemiol. Prev. 39, 8–13 (2015).

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    Maintaining the common grounds. Nature Plants 3, 755 (2017).

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