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Growing Cities


Over the past century the unstoppable force of development has gradually squeezed green space out of our world’s major cities.

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READ NO.2

READ NO.2

Words by Tom Ravenscroft

Fortunately, in recent years there has been a turning of the tides, as architects and urban planners have begun innovating to reintroduce green into our cities. They are creating a new generation of ‘natural’ landscapes, which, ironically enough, means artificially engineered green spaces. Developers are taking advantage of cutting edge technology to bring green bridges, green towers, and super-charged greenhouses to some of the world's largest and densest metropolises.

Contact with the natural environment is a fundamental requirement of human well-being. Ever since urbanisation first took hold in the 19th century, the most desirable locations in a city have been alongside green land. Whether the private squares of London or the public parks of New York and Paris, closeness and contact with green space has always been at a premium. In the modern city, organic opportunities to experience green space have been dramatically reduced, leaving residents yearning for nature

Going green
It started in New York. An abandoned elevated train track in central Manhattan provided the ideal opportunity to insert a sliver of green back into the concrete jungle. The raised railway track, now known as the High Line, was saved from demolition in 1960 and again in 1991, and has since been transformed into a 1.45 mile long urban greenway. Conversion of the track began in 2006, and the final section opened to the public last year. It was through clever design and progressive planning that a redundant section of the city's transport infrastructure has been re-engineered into a park; to the obvious benefit of the city. Now, this public space provides a green escape for five million locals and tourists every year.

The extraordinary success of the High Line, undoubtedly driven by its inhabitants’ hunger for green, has led to cities across the globe seeking to recreate the success. Lucky for New York, the city had a space to colonise. The reality, however, is that most urban areas do not have a disused railway ready and waiting for conversion. Rather, city planners, architects and designers have had to drive innovation in an effort to find unique ways to engineer green spaces into the dense fabric of their existing city.

  • The Highline walkway, built on
    disused train lines across New York.
    Image: Friends of Highline

The Highline walkway, built on
disused train lines across New York.
Image: Friends of Highline

The urge for green means
trees are finding their homes in environments where they have never grown before.

Green on top
A tried and tested method of engineering nature into a city is through green roofing – effectively transplanting the outdoor space lost at ground level onto the roof of a building. This concept has been around for centuries; the Hanging Gardens of Babylon are a wondrous early example. The scale and ambition of modern roofs has grown substantially since its beginnings in Germany some 40 years ago, when the technology that allowed grass to be seriously considered as a viable roofing material was developed. What began on small-scale homes was quickly adapted for larger buildings, such us Norman Foster's seminal High Tech work, the Willis Faber and Dumas Headquarters in Ipswich, England (1975). Here, a grass covered roof acts as a private recreational space for the company's employees.

Green roofs are now popular all over the world, with progressive tech companies such us Facebook, keen to provide their employees with the best working environments available.The social media giant's new Silicon Valley HQ, designed by starchitect Frank Gehry, opened in March this year is topped with a 3.5-hectare rooftop park. On it you’ll find a halfmile walking trail and over 400 trees.

Onward and upward
Along with advances in the scale of green roofs, which are mostly utilised on low rise buildings, architects are becoming ever more ambitious in addressing the mounting concerns about loss of green space in cities. They are now looking upward. As there is no building more synonymous with the dense modern city than the skyscraper, it is perhaps fitting that this building type is now providing the greatest opportunity to engineer green back into the city.

Throughout the early 2000s, futuristic visualisations of tall towers covered in trees were appearing on eco-blogs, and now the once improbable concept of a ‘green skyscraper’ has become a reality. Technology evolved from green roofing is being utilised to allow large-scale planting to be incorporated into tall buildings around the world.

The latest skyscraper in the City of London, 20 Fenchurch Street (nicknamed the Walkie Talkie), is an example of these next generation green towers. Designed by Rafael Viñoly the skyscraper is unique in the city as it topped with a ‘sky garden’. The 37th floor of the tower is a park, comprised of trees, plants and other soft landscaping. This freely accessible space is an asset for the city, where the building’s employees and London’s public can escape to a calm green space far above London’s busy streets.

The Bosco Verticale in Milan.
Image: Paolo Rosselli

A green waterfall in the Park Roal at Pickering Hotel, Singapore. Image: Patrick Bingham-Hall

  • The Bosco Verticale in Milan. Image: Paolo Rosselli

  • A green waterfall in the Park Roal at Pickering Hotel, Singapore. Image: Patrick Bingham-Hall

From Seoul to the States, in the world’s greatest cities architects across the world are responding to the same need, the same desire to reintroduce nature into our urban landscapes.

In another of the world's densest cities, Singapore, architects WOHA have built a tower that doubles the green-growing potential of its site. Three towers of the Park Royal Hotel are connected by massive curvaceous sky gardens, cantilevered off the building at every fourth level. These green terraces are draped with tropical plants and support swathes of frangipani and palm trees.

Perhaps the most ambitious of this new generation of green skyscrapers is Stefano Boeri's vertical forest, which is nearing completion in Milan. The twin towers measure 80 and 112 metres high, and have been developed with the aim of combining high-density residential development with extensive tree planting in city centres. The building incorporates an astonishing 900 trees on balconies, covering all four sides of the towers. Boasting as many trees as could be planted in a hectare of forest, along with 2000 plants from a wide range of shrubs and floral plants, this truly green skyscraper will allow its residents constant contact with the great outdoors.

Green urban sprawl
Efforts to bring green into the city are not only happening at height. In London, plans for a public garden that will stretch across the River Thames won planning early this year. Intended to be an oasis in the centre of London, the Garden Bridge is being designed by the architect of the 2012 Olympic cauldron, Thomas Heatherwick. The £175 million bridge will be covered with 270 trees as well as shrubs, climbing plants, hedges and flowers supported in deep soil filled trenches.

As demonstrated by the Garden Bridge, green skyscrapers and Facebook’s rooftop, the urge for green means trees are finding their homes in environments where they have never grow before. Engineering is allowing us to control environments, growing plants where they wouldn’t naturally thrive. This is an idea that first started in the 17th century winter gardens of UK country homes and has now developed as far as ‘the super greenhouse’.

In a bid to grow plants that could never naturally survive in its hot and humid climate, Singapore has recently built two great climate-controlled glasshouses. A reversal on the traditional greenhouse, these glazed enclosures are cooled to create artificial environments where new, migrant plants thrive.

Designed by London-based architects Wilkinson Eyre, the cooled conservatories are the centerpiece of a 100-hectare park, built on reclaimed land, named Gardens by the Bay. Two distinct environments have been recreated in the glasshouses that cover a combined 20,000m2. In the first glasshouse a dry Mediterranean climate has been replicated, while in the taller of the two structures the moist environment of a cloud forest has been reproduced complete with an artificial mountain and a 35 metre high waterfall.

An integral part of Singapore’s drive to become a ‘city in a garden’, the glasshouses are not only an asset to the city as a public amenity, but also a victory over nature.

Not a city to be outdone, Dubai plans to challenge nature even further by attempting to recreate a rainforest in the desert. Housed in a dome, if the proposed water-hungry scheme is ever built, it may be the largest demonstration of engineering a natural environment yet.

  • The 50m tall Supertree Grove in Singapore. Image: Gardens by the Bay

The 50m tall Supertree Grove in
Singapore.
Image: Gardens by the Bay

Green scaling
Germany, the original home of the green roof, is now responding to the green challenge on an urban scale. In Stuttgart, the city is burying its central station and miles of track underground to release 100-hectares of land to be developed and used as parks. Interestingly, Stuttgart is not the only German city to be burying its infrastructure. In Hamburg, a two-mile section of the city’s main highway is being covered to create a series of parks that will become a sprawling river of green running through the city

This drastic action echoes developments on the other side of the world in Seoul, South Korea. Here, an elevated six-lane highway built during the 1970s has been removed, and in its place, a historic river was reinstated to create the city’s newest linear park. From Seoul to the States, in the world’s greatest cities, architects across the world are responding to the same need, the same desire to reintroduce nature into our urban landscapes. Whether on bridges, skyscrapers or in glass houses, architects are adding green in ways that have never been seen before.

Although the trend to introduce green into the city was originally driven by sustainability concerns, with environmental impacts of green walls and green roofing heavily promoted and even tax incentivised, it has been overtaken by a desire for interaction with nature. City dwellers are demanding physical and psychological space, and architects are revelling in the challenge and engineering solutions that allow nature to exist in the most unnatural locations.


Growing Cities


  • Growing Cities

  • The Highline walkway, built on disused train lines across New York. Image: Friends of Highline

  • OThe Bosco Verticale in Milan. Image: Paolo Rosselli

  • A green waterfall in the Park Roal at Pickering Hotel, Singapore. Image: Patrick Bingham-Hall

  • The 50m tall Supertree Grove in Singapore. Image: Gardens by the Bay