會自我生長的建築／印度利用植物長出來的吊橋！

Living Infrastructure:

在河流湍急的國家裡，造橋的方法使用硬碰硬的鋼筋水泥並不是唯一的選擇，在台灣，由於官方勾結，河流的溪石被採集殆盡，失去溪石的護衛，台灣一遇天災，橋樑應聲斷裂時有所聞，於是台灣人開始去思考懸臂橋；在印度Meghalaya的Nongriat這個地方，五百年前早就用自然生存的方法，他們利用植物的生長來造出超過100英呎的橋，能夠同時負重50個人，甚至是雙層的植物橋，這不是建築的新思維，而是我們遺忘的方法罷了。

本文除了附上詳細的植物自然生長的橋外，也有影片一則，詳細介紹這橋的製作方法，影片的另一段是描繪BBC團隊如何生成一支好的記錄片的辛勤過程，有趣的朋友可以整支看完，非常精彩。

Photo: Daily Mail

Growing your own house may seem like a new idea, but what about growing pieces of functional infrastructure? That’s exactly what the locals of Nongriat in Meghalaya, India have been doing for the past 500 years. In that time, they’ve grown bridges over one hundred feet in length and strong enough to support the weight of more than 50 people. There are even “double decker” bridges! More after the jump!

The fifteen meters of annual rainfall of the Cherrapunji region–a figure aggrandized by frequent flash floods–accelerate the flow of its rivers and streams, the fierceness and destructive power of which few wooden or steel bridges could withstand. Transport across the region’s numerous water channels is necessary, whether to return to one’s dwelling after fishing or clothes washing or to escape the dangers of one place to move to another. But how?

The locals’ answer lie in the sloping hills hugging the contour of the water channels, where a species of rubber tree flourishes. From the upper trunk of the ficus elastica, secondary roots grow outwards with great profuseness. The tribes people realized half a millenia ago that they could use these roots to forge a pass across the water below, using hollowed out betel nut trunks to guide the direction of the roots’ growth.

Photo: Daily MailOnce the roots make their way across the water to the opposite bank, they take hold. Here, they continue to grow and strengthen, not only stabilizing the bridge platform, but also reinforcing the bank walls. The full cycle of bridge-growing may take ten to fifteen years to complete, necessitating the locals’ aboricultural knowledge to be passed on from older to younger generations, who will, perhaps, personally continue the former’s work.

Photo: flickr user Vanlal

Photo: flickr user Vanlal