A living root bridge is formed by guiding the pliable roots of the
rubber fig tree across a stream or river, and then allowing the roots to grow and strengthen over time until they can hold the weight of a human being. The young roots are sometimes tied or twisted together, and are often encouraged to combine via the process of
inosculation. As the rubber fig tree is well suited to anchoring itself to steep slopes and rocky surfaces, it is not difficult to encourage its roots to take hold on the opposite sides of river banks. A root bridge can be made in several ways:
By hand Some living root bridges are created entirely by manipulating the roots of the rubber fig tree by hand, and without the aid of a scaffolding or any other natural or human-made materials. Often, locals using root bridges will make small alterations to them, manipulating young roots as the opportunity presents itself. Because of this, one can say that the development of a living root bridge is very much a social endeavor and that the structures are perpetual works in progress.
Wood or bamboo scaffold Root bridges are also commonly formed by training young rubber fig roots over scaffolds made from wood or bamboo, materials which are abundant in Northeast India. In these instances, the roots are wrapped around the outside of the perishable material. The scaffolds may be replaced many times over the years as the root bridge becomes stronger.
Conventional structures Root bridges can also be trained by guiding the young roots of rubber fig trees across conventional structures, such as already existing steel wire suspension bridges. As the structure being used as a scaffold is already functional, the problem of the length of time it takes for a root bridge to become functional is here essentially bypassed; the conventional structure can be used until the more sustainable root bridge is sufficiently strong. == Distribution ==