Die Eroberung des Himmels © Firma WOHA

Reaching for the sky to claim green space

Jan Zimmermann
Jan Zimmermann
Editor of mapolis architecture magazine

Throughout by far the longest epoch in human history since the very dawn of our species, the natural landscape in which we lived was “untouched”. During that entire period of our existence, humanity’s impact on the face of this planet was no greater than that of most mammals. The first forms of buildings, although positively pioneering in primeval times, would ultimately be seen as no more spectacular than a beaver’s lodge. It was not until a couple of thousand years ago that humanity then suddenly started in some places to demonstrate such creativity that significant tension developed between what had existed before and the structures mankind was now building. This creativity has, since then, encompassed most of the globe and, when we weigh the balance of tension between pristine nature and nature that has been touched by the hand of mankind, the latter predominates by a long way. In fact, untouched nature is increasingly disappearing with ever-proliferating human population figures.

The rationale behind this development – the civilization of our earth – should even today be the need for shelter and security: shelter against the elements, predators and even other human beings; security in the form of a safeguarded subsistence. The first aspect of this need is met by living space, the second, nowadays, by work. And as in many ways living space also depends on work, most people are consistently drawn to where the probability of obtaining a job seems highest: the big cities. Unfortunately, however, the resource of space is not always symmetrical with the resource of work, and that is why, in places where the highest number of people want to live or can best hope to survive, space is generally in short supply.

Green nostalgia

The primal urge to safeguard our existence which preceded our intervention in nature runs counter to another, equally ancient urge. I say “ancient” because it might be viewed as a nostalgia, a homesickness for our original ancient habitat – the need for green. Undoubtedly this primarily aesthetic need is subordinate to the need for a secure existence. And yet it is just as important to us as having beauty in the world that surrounds us, so we try, by any means possible, to procure this beauty for ourselves. For some years, with our increasing awareness of climate change, green spaces have also been considered to be an important climatic factor. Green or open areas indeed, just like housing and jobs, mainly require one thing: space. As however space is already at a premium in big cities and towns, open spaces having to take second place below the more urgent existential needs for housing and work, green space is even scarcer there. What should be done then when spaces are built over and there is no room for green? The answer is often more obvious than it would at first appear. All you need to do is look in the right direction.

Green verticals

Some people, when they are seeking the answer to a problem, look to the heavens and pray to God or the universe or whatever they believe they are able to appeal to up there. At some point, someone must have done that very thing when looking for a solution to the problem of space in big cities and realized “Just a moment, there’s still an awful lot of space up there!” As early as at the end of the 19th century, following this ground-breaking realization, people began to use vertical space. The result was what we now call ‘skyscrapers’. Multi-storey residential blocks and office buildings have been a fixture of the world’s cities ever since. Therefore it was indeed only a matter of time before someone looking for space for green areas would also look skyward and reach the same conclusion. There has, in fact, for several years now, been a veritable trend in vertical green spaces.

Facade greening (for example using ivy) has existed for some centuries and other forms of building greening such as grass roofs are not exactly a new thing. The completely new trend I am referring to is something quite different. On the one hand green spaces have been emerging recently in places where they simply did not exist before. On the other hand, only in recent years have new methods been in use that permit facade greening using ordinary non-climbing ground-cover plants.

Old ways, new green

Currently the most prominent example in this new category is High Line Park in New York City. This is an overhead railway, approximately 2.33 km long, disused since the 1980s, which, in 2006, began its three-stage transformation into a park. The third and final phase has just recently been opened (on 21.09.2014). This green triumph, rightly celebrated in the media, delightful as it is, however, does have a predecessor by 15 years: the Promenade Plantée in the 12th arrondissement in Paris. This park too has been planted on the disused tracks of an overhead railway and is twice as long as High Line Park in New York. Yet even though the Promenade Plantée has already been there for quite a while, the urge to imitate this concept all over the place only really seems to have taken off since the New York version. For example, a similar project has been several years in the planning in Chicago for the Bloomingdale Trail, and comparable schemes are under way in Philadelphia and St. Louis. Even in Vienna, the idea of transforming the old U6 line to Heiligenstadt into a ‘High Line Park Vienna’ has at least been toyed with. The residents of all cities who have no overhead railways and therefore will never know the delights of such a greenway however have no reason to hang their heads in despair. There are other ways.

Vertical gardens

Admittedly, the examples mentioned are all aerial, which certainly marks them out as something special, yet fundamentally they are conversions of disused tracks into green spaces, and these exist at ground level too. I have already mentioned a different aspect of the trend in green verticality based on more recent technical achievements in the sphere of facade greening. To be honest, the invention I am about to report on isn’t really new either. Back in 1938, Stanley Hart White, a professor of landscape architecture, patented his ‘Green Wall’, enabling the planting of walls with plants not rooted in the ground. What is needed for such a green wall is a medium which keeps plants vertical and feeds them. Ahead of its time as it obviously was, this invention did not catch on for a long time. It would need someone like Patrick Blanc to lead the world into a new era of green walls. This French botanist developed his first ‘vertical garden’ at his home in 1982. These gardens use acrylic felt as a medium and have their own closed-circuit watering system.

Even in Patrick Blanc’s case, however, it took a while for the concept of the vertical garden to become established. But now his gardens decorate the walls of highly prestigious buildings such as those of the CaixaForum Madrid by Herzog & de Meuron, and have attracted numerous imitators who, in turn, have further developed their own media and irrigation systems. The wonderful thing about these vertical gardens is that they enable a much wider variety of plants to be grown. But that isn’t all. As planting is not ground-based, it manages completely without horizontal surfaces and therefore is eminently suited to bringing the green back to built-up urban areas. However, one disadvantage of vertical gardens as opposed to ground-based climbing gardens is that they are relatively expensive in terms of the technology needed to construct, care for or maintain them and therefore are ultimately far more expensive.

Where do we want to grow to?

One thing seems certain: there is still plenty of room to go upwards. Yet the question remains as to what countermeasures we should take against every available piece of open space becoming overgrown with a proliferation of concrete and asphalt. Do we simply go upwards or should we stop things getting to that stage well before it happens? Or perhaps both, as WOHA has done in Singapore with its Parkroyal in Pickering? The latter is a series of giant terraces and green walls forming a 15,000 m² natural living landscape, which is not only the most distinctive feature of this hotel and office building, but is also an extension of the park in front of it, only half the size. The same architectural practice devised a concept for a vertical city designed to meet the needs of 100,000 people in a single square kilometer. This is a science-fiction vision of urban self-sufficiency, consisting of thirty towers stacked on top of one another in rows after the style of the Burj Khalifa. The facades here are planted with vertical gardens and on horizontal structures there are fields and wind parks many hundreds of meters in the air. Green is everywhere here and dominates this futuristic landscape. But is it a green Utopia? Such visions are feasts for the eyes, but do we really want to go there?

Regardless of whether our horizontal open spaces are all concreted over by the metropolises of the future, or whether they are spared; regardless of whether we are eager or forced to go upwards: presumably we can rejoice that there are innovative spirits such as Patrick Blanc around to point us in new directions and there is general willingness to travel new, green ways, as has been the case in New York.

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