绿色屋顶 Green Roofs

绿色屋顶 Green Roofs




绿意罩顶
假如建筑物像香菇一样突然从地上冒出来，那么它们的屋顶上就会覆盖着一层泥土和植物。
当然了，人类并不是这样盖房子。我们会刮除土地、立起结构体，然后在顶端罩上一个想必盖好就会被人遗忘的防雨屋顶。虽然很想说地球上每座城市的屋顶景观都像一片人造沙漠，但沙漠好歹也是个活生生的栖地。事实比这更惨。都市的屋顶景观有一点像地狱──是个了无生机的地方，充斥着涂了沥青的表面、极端的温度对比、凄厉的风，以及对水的排斥。
If buildings sprang up suddenly out of the ground like mushrooms, their rooftops would be covered with a layer of soil and plants.

That's not how humans build, of course. Instead we scrape away the earth, erect the structure itself, and cap it with a rainproof, presumably forgettable, roof. It's tempting to say that the roofscape of every city on this planet is a man-made desert, except that a desert is a living habitat. The truth is harsher. The urban roofscape is a little like hell—a lifeless place of bituminous surfaces, violent temperature contrasts, bitter winds, and an antipathy to water.


但若是从天窗跨出去、踏上加拿大温哥华图书馆广场上温哥华公共图书馆的屋顶（位于市中心，有九层楼高），你就会发现自己置身于一片草原，而不是沥青荒地。它是一片空中草原。就算只是在地面，这座1995年由景观设计师柯妮莉雅‧奥伯兰德设计、面积1850平方公尺的花园，也够引人注目了。在温哥华上方高处，那效果几乎让人错乱。当我们爬上城市的楼顶时，通常是为了眺望风景。然而身在这座图书馆的屋顶，我不禁觉得自己就站在风景里──在这么多玻璃、钢筋与水泥之间，竟然有这么一片令人意想不到的绿色、蓝色和棕色草地。

But step out through a hatch onto the roof of the Vancouver Public Library at Library Square—nine stories above downtown—and you'll find yourself in a prairie, not an asphalt wasteland. Sinuous bands of fescues stream across the roof, planted not in flats or containers but into a special mix of soil on the roof. It's a grassland in the sky. At ground level, this 20,000-square-foot garden—created in 1995 by landscape architect Cornelia H. Oberlander—would be striking enough. High above Vancouver, the effect is almost disorienting. When we go to the rooftops in cities, it's usually to look out at the view. On top of the library, however, I can't help feeling that I'm standing on the view—this unexpected thicket of green, blue, and brown grasses in the midst of so much glass and steel and concrete.


有生命的屋顶并不是新玩意。它们在美国大草原上的草皮屋很常见，而北欧的木屋与木棚上也还找得到草皮屋顶。但近几十年来，全球各地的建筑师、营建商与都市计划师都开始发展绿色屋顶，不是为了美观（那是后来才想到的），而是为了它们的实用性，以及它们可以缓和传统屋顶上常有的极端环境条件。
Living roofs aren't new. They were common among sod houses on the American prairie, and roofs of turf can still be found on log houses and sheds in northern Europe. But in recent decades, architects, builders, and city planners all across the planet have begun turning to green roofs not for their beauty—almost an afterthought—but for their practicality, their ability to mitigate the environmental extremes common on conventional roofs.

从图书馆出发，市区另一侧的温哥华会议中心也正在建造一个新的活屋顶。同一条街对面，菲尔蒙水岸饭店的屋顶有一座厨师的香料花园。再往市区的另一个方向，正为2010年冬季奥运而兴建的一座奥运村也将会有绿色屋顶。站在温哥华──或芝加哥、或司徒加、或新加坡、或东京──的绿色屋顶上，就可以瞥见我们城市的屋顶景观可能有多么不一样，并且纳闷：我们以前怎么一直都没有这么做呢？
Across town from the library, the Vancouver Convention Centre is getting a new living roof. Just across the street there is a chef's garden on the roof of the Fairmont Waterfront hotel. Across town in another direction, green roofs will go up on an Olympic village being built for the 2010 Winter Olympics. To stand on a green roof in Vancouver—or Chicago or Stuttgart or Singapore or Tokyo—is to glimpse how different the roof­scapes of our cities might look and to wonder, Why haven't we always built this way?

科技只是一部分原因而已。如今防水膜让绿色屋顶系统的设计变得更容易，可以捕捉水分以灌溉、进行排水、支持生长培养基，并防止植物的根入侵。在某些地方，例如美国奥勒冈州的波特兰，便透过营建费用降低或其它诱因鼓励营建商采用活屋顶。在其它地方（如德国、瑞士和奥地利），倾斜角度适当的屋顶依法必须采用活屋顶。
而且，有愈来愈多像莫琳‧康纳利（她在加拿大卑诗理工学院主持一个绿色屋顶实验室）这样的研究者在研究绿色屋顶带来的实际利益，协助量化它们的成效，并提供准确的测量数据，具体呈现它们减少暴雨径流、提升能源效率，以及改善都市噪音的能力。世界各地的绿色屋顶已经开始达到临界数量，每个屋顶本身都是一个实验。


Technology is only partly the reason. Waterproof membranes now make it easier to design green-roof systems that capture water for irrigation, allow drainage, support the growing medium, and resist the invasion of roots. In some places, such as Portland, Oregon, builders are encouraged to use living roofs by fee reductions and other incentives. In others—such as Germany, Switzerland, and Austria—living roofs are required by law on roofs of suitable pitch.

And, increasingly, researchers such as Maureen Connelly—who runs a green-roof lab at the British Columbia Institute of Technology—are studying the practical benefits green roofs offer, helping quantify how they perform and providing an accurate measure of their ability to reduce storm-water runoff, increase energy efficiency, and enhance the urban soundscape. There is beginning to be a critical mass of green roofs around the world, each one an experiment in itself.