In Northeast India amongst the jungle lies Cherrapunji.Cherrapunji is just about the wettest place on earth, the southern Kasi and Jaintia hills are extremely warm and humid, covered in a fine network of streams and fast flowing river. As such it is often best to have a bridge over these troubled waters; in Cherrapunji though, they are not built, instead they are grown.
The Ficus Elastica is a special type of rubber plant which thrives in the humid hills, producing rich root networks which were both extensive and sturdy. Long ago the War-Khasis tribe noticed that they had a second root network, higher up in the trunks a second set of roots would dangle down, the humidity so great that these roots could suck minerals from the airborne moisture. The War-Khasis weren’t so big on being amazed at extreme humidity and capillary action, instead they saw an opportunity. These trees grew near everywhere, so whenever they wanted a bridge, they found these trees and grew them. With a little direction of course.
To make sure that the upper roots grow in the correct direction, ie horizontally over a valley or river, they cut another tree in half.Specifically the bezel nut tree trunk is split in two and hollowed out, forming a long half-pipe. This is then strapped to the tree and pointed over to the other side; the raised sides of the trunk force all of the roots to venture out over the respective chasm, and they do. They just keep growing until the roots reach the other side. Then they are allowed to take root in the soil.This is the start of a living bridge. Over the course of the next 10-15 years the War-Khasis encourage, well really just let other roots grow down the trunk and direct others up the sides to form living handrails. Every single day the bridge becomes stronger until by the end of the 10 or so years it is complete, a big living bridge, the bezel nut trunk is removed and the remaining root structure is immensely strong, some can hold upwards of 50 people.
The remarkable thing about these bridges is simple the fact that the trees live and in fact thrive, constantly they put out more roots and strengthen the other, the bridges only improve with age, as do their hand rails. In fact the bridges can last near indefinitely, some root bridges in the vicinity of Cherrapunji have been growing for over 500 years and aren’t going to stop any time soon, they are firmly rooted in bridge construction.
There is one bridge of special significance, the Umshiang Double-Decker Root Bridge. This tree has produced two bridges, one above the other. A feat that has not been matched anywhere in the world, it is one-of-a-kind. It is also a fantastic example of how working with, not against nature can help humans without the waste of resources. Sure it is a bit slower, but it’s much cooler than some steel structure. However the locals were rather skeptical of this, they had plans to cut down the root bridges and replace them with steel equivalents, it was only when the bridges were rediscovered by Denis P. Rayen that they learnt of the potential worth of their existing living bridges. So today all of the root bridges stand, in fact a new one is being grown at this very moment, it should be complete within a decade. Personally I can’t wait.