~Living Root Bridge

In the depths of northeastern India,
one of the wettest places on earth, bridges
aren’t built – they’re grown.
  
The living bridges of Cherrapunji, India are made
from the roots of the Ficus elastica tree.
This tree produces 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.

In order to make a rubber tree’s roots grow in
the right direction – say, over a river – the Khasis use
betel nut trunks, sliced down the middle and
hollowed out, to create root-guidance systems.

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.

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