Saturday, April 23, 2011

Natural Architecture - Living Root Bridges

Talk about being one with nature. In the depths of northeastern India, in one of the wettest places on earth, bridges aren't built - they're grown. Vastly superior to man-made bridges, these bridges are safe, organic, environmentally-friendly and, oh so, natural. Unfortunately, the vast majority of us can only dream of living in such a serene, tranquil place where life is truly one with nature.

All pictures courtesy: rootbridges.blogspot

The living bridges of Cherrapunji, India are made from the roots of the Ficus elastica tree. These trees are a relative of the fig tree - ficus; and, I think the elastica says the rest. They produce a series of secondary roots from higher up its trunk and can comfortably perch atop huge boulders along the riverbanks, or even in the middle of the rivers themselves. These secondary roots can be trained for use as a second level to the bridge.

Cherrapunji is credited with being the wettest place on earth; so, there can be many water obstacles to cross. The War-Khasis, a tribe in Meghalaya, long ago noticed this tree and saw in its powerful roots an opportunity to easily cross the area's many rivers. Now, whenever and wherever the need arises, they simply grow their bridges. Please see the video at the end of this blog to see a root-bridge under construction - so to speak.

In order to make a rubber tree's roots grow in the right direction - over a river, for example - the Khasis use betel nut trunks, sliced down the middle and hollowed out, to create root-guidance systems. Using methods to redirect a plant's growth have been used for centuries all over the world. Bonsai is probably the most well-known method of plant growth manipulation in the world.

The thin, tender roots of the rubber tree, prevented from fanning out by the betel nut trunks, grow straight out. When they reach the other side of the river, they're allowed to take root in the soil. Given enough time, a sturdy, living bridge is produced.

The root bridges, some of which are over a hundred feet long, take ten to fifteen years to become fully functional; but, they're so extraordinarily strong that some of them can support the weight of fifty or more people at a time. Pretty impressive!

Because they are alive and still growing, the bridges actually gain strength over time. The bridges are self-maintaining as they just grow new plant material over defects making the root bridges vines larger as they age. Some of the ancient root bridges used daily by the people of the villages around Cherrapunji may be well over five hundred years old. I would love to cross a 500-year-old root bridge; but, there is no way I could be convinced to cross a 500-year-old western bridge that spanned a river.

One special root bridge, believed to be the only one of its kind in the world, is actually two bridges stacked one over the other and has come to be known as the "Umshiang Double-Decker Root Bridge."

Video showing a living-root bridge under construction.

Via rootbridges.blogspot

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