How are Living Root Bridges Made?

A living root bridge is created using the pliable aerial roots of the ficus elastica species of fig tree. The natural growth of the roots is harnessed in such a way that they are gradually trained into the desired architectural structure, using both their tendency to anchor themselves to other objects and their propensity to combine with each other via the process of Inosculation. This can take many years, though the exact amount of time necessary for a root bridge to become functional is highly variable, and dependent on local factors such as how healthy the tree is, how flood-prone the stream the bridge crosses is, how much those crossing the bridge mind wobbly roots, and what level of community involvement there is in developing the structure.

Based on my investigations, it’s clear that there are several methods of generating a usable living root bridge, and these methods vary from example to example and from area to area. However, it is important to note that in all instances the creation of a living root bridge is very much a long-term, social, process, with additions and improvements being made well after the initial planters have died. After a root bridge’s initial period of development, it is reinforced when people using it simply rearrange the naturally growing roots found on the span in an opportunistically beneficial way.  Because of this, root bridges can be seen as continual works in progress, with many successive generations contributing to them. An example that’s hundreds of years old is still part of a living, changing, developing, organism.

Unfortunately, given that the practice is fading in so many areas where it was once widespread, and that newly created living root bridges are so rare (especially outside of tourist areas), it’s difficult to observe new bridges under construction using traditional methods. It may well be that a greater body of expertise on the subject once existed, but has since faded. Often, there is very little information about how a given bridge was initially formed.

I’ve arranged the methods of creating living root bridges into four broad groups. Bear in mind that, given the organic nature of the structures in question, the construction of a single bridge might involve several, or even all, of these. There is often overlap between methods.

The methods are:

a): Root bridge training without scaffolding.

b): Root bridge training using bamboo or wood scaffolding.

c): Root bridge training using hollowed out Areca Palm trunks.

d): Root bridge training using steel wire.

ROOT BRIDGE TRAINING WITHOUT SCAFFOLDING

IMG_1350
Inosculation of young roots. The strands were twisted together by hand, and then merged with one another naturally. By encouraging this process, individuals creating living root bridges combine the strength of separate ficus elastica roots.

Almost all living root bridges that I’ve observed which were still being actively maintained showed signs of roots that had been manipulated by hand to improve the functionality of the structure. These improvements often took the simple form of a few individual roots that had been wrapped around each other, tied to trees, or attached to the opposite bank of a stream. I’m told that these ad-hoc, spur of the moment improvements are usually done by people working in the jungle, who have occasion to use the living root bridge, and so take it upon themselves to improve the structures over time.

The people making these improvements understand that, gradually, individual roots tied or twisted together will merge, forming a stronger overall structure.

The slideshow below shows a living root bridge where virtually all of the recent maintenance has been in the form of roots being manipulated by hand, without the use of a scaffold.

 

This slideshow requires JavaScript.

For more information on this bridge, go to: Laitiam 1

While the methods used in the initial generation of many older bridges is often not clear, I have seen examples where no scaffolding was ever used, and where the structure was formed entirely by manipulating roots by hand.

IMG_2717
Here, very young ficus elastica roots have been wound together by hand in the hope that they will grow together and one day be able to hold the weight of a person. The photo is from the span of a living root bridge in the Rangthylliang village area.

The northern span of the double root bridge pictured below was generated entirely without the use of a scaffold, and all maintenance and further development of the span has been done by hand. The span was first brought into existence by the man in the red shirt you can see working in the pictures.

 

This slideshow requires JavaScript.

For more information on this bridge, go to: Burma 1

The slideshow below shows a damaged living root bridge undergoing significant repairs, most of which are in the form of aerial roots simply being tied together and readjusted (though some bamboo is also used). I visited the same bridge a year later and found many of the manipulated roots still in place.

 

This slideshow requires JavaScript.

ROOT BRIDGE TRAINING USING WOOD OR BAMBOO SCAFFOLDING

IMG_2826
Work being done on a root bridge in development. Here, an extensive scaffold made of bamboo and wood has been built around a few already established roots. The person in the foreground is guiding very young strands around the outside of the scaffold. When this photo was taken the bridge was usable, though much of the stress seemed to be taken by the scaffold. This demonstrates one way that a root bridge can become immediately usable. Until the time when the roots become strong enough to walk across, the structure used to guide the young roots can serve as a temporary bridge.

Many root bridges are created using scaffolds made of wood or bamboo, materials which can be found virtually anywhere in Southern Meghalaya.

In these instances, young ficus elastica roots can often be seen twisted around bamboo poles, while sticks and tree trunks are used to add additional stability to a temporary structure which crosses a stream and is used to aid in the formation of a botanical structure. While these materials rot quickly in the hot, humid, climate of Southern Meghalaya, given their ubiquity, they can easily be replaced from year to year.

The roots, providing the tree they are a part of remains healthy, gradually become stronger and thicker, and with many adjustments to the scaffold over time, will slowly develop into a functional living root bridge. Once the roots can be safely walked upon, the scaffolding is no longer necessary. However, additions and repairs to already functioning root bridges are still often made by guiding aerial roots along the outsides of sticks, tree trunks, or bamboo poles.

This method of root bridge creation appears to be practiced throughout the area where they are found. In some areas, root bridges are also created using a method employing hollowed out Areca Palm trunks (see the next section).  However, in areas where Areca Palms do not grow in abundance, the use of wood or bamboo scaffolding is simply more practical.

I’ve also had the opinion expressed to me that the Areca Palm method is more time consuming, meaning that even in some areas where Areca Palms are common, the locals still opted to use a bamboo or wood scaffold because they thought that would be easier.

IMG_0508
Here, a new span for a pre-existing living root bridge is being generated. The two straight lines near the top of the photo are where young roots are being guided along bamboo poles. The structure has developed significantly since this photo was taken.
IMG_0516
This is a picture of the same bridge, taken from above the span that is being generated. Here you can see how the new span is being trained by wrapping young roots around the sticks and bamboo poles.

The photos below are of a root bridge where a scaffold has been created very recently, even though the primary root of the structure is fairly well established.

 

The slideshow below depicts a root bridge which existed as a few strands strung across a stream in 2015, though it was later significantly developed using a bamboo and wood scaffold.

 

This slideshow requires JavaScript.

ROOT BRIDGE TRAINING USING HOLLOWED OUT ARECA PALM TRUNKS

IMG_2270
Ficus elastica roots that have been trained through an Areca Palm trunk in order to develop  a living root bridge. Here, one can see how the decomposition of the Areca trunk provides the roots with nutrients.

The most well known method for creating living root bridges is to use the hollowed out trunks of Areca Palms. These are placed across streams and rivers, and then young ficus elastica roots are guided through them. The trunks serve to direct the roots, to protect them, and also to provide them with nutrients as they decompose. In this way, a strand guided across a stream using an areca trunk has a solid chance of growing thick enough to become a useful part of an architectural structure. Usually, the hollow trunks are incorporated into some variety of wood or bamboo scaffolding.

There are only a few instance where this method of root bridge generation can be observed, and these are mostly in tourist areas. Here, the scaffolds that incorporate hollowed out Areca Palm trunks often also employ steel wire and other materials.

IMG_2266
Ficus elastica roots being directed through a hollowed-out Areca Palm.
IMG_2273
A view of the scaffold being used in the creation of a new third span on the famous Nongriat Double Decker root bridge. Note the variety of materials being employed here, including wood, steel wire, and bamboo strips.

This means of creating living root bridges is practiced around the village perhaps best known for its living root bridges: Nongriat. This is a tourist friendly area, and so the use of Areca Palm trunks can be easily observed not only in Nongriat village, but also in the nearby settlements of Nongthymmai and Mynteng.

 

The photos above show a new railing being grown on a tourist-frequented root bridge near the village of Nongthymmai using ficus elastica roots directed through an Areca Palm trunk. Wires and bamboo strips are also being used.

IMG_2178
Another view of the same new railing (the structure at the upper right) that was being generated as of 2016.
IMG_2060
Young ficus elastica roots being trained through a hollow Areca trunk, near Mynteng Village, which is next to Nongriat.

 

ROOT BRIDGE TRAINING USING STEEL WIRE

IMG_2261
Here, ficus elastica roots have been wrapped around a steel cable and then allowed to develop naturally. This is part of a hybrid structure composed of roots, steel, and concrete.

While it is not common, it is possible to develop living architecture using steel wire. Though conventional elements have often come to replace root bridges entirely, in a few places they have been incorporated into living structures.

Near the village of Nongriat, there is a particularly interesting example of a “hybrid” structure, where ficus elastica roots have been trained across a pre-existing steel wire bridge. Here, the immediately usable, conventional, structure doubled as a scaffold on which to develop a root bridge. As the roots have grown and gained in strength, the steel wires have become effectively redundant, and will probably be allowed to rust away sometime in the future. In this way, the long phase of root bridge development during which the structure is not usable because it is still too young and its roots are too thin has effectively been bypassed.

This slideshow requires JavaScript.

In some examples of recently damaged or recently developed living root bridges, steel elements have been used to repair and help regenerate the structures.

IMG_2284
This is part of a large, though badly damaged, living root bridge in the vicinity of Nongthymmai village. Here, a large part of the root bridge has been removed and replaced with steel wire in order to provide a functioning railing. However, an attempt is being made to create a new “living” railing, using the Areca Palm method.

In the village of Nongpriang, there is a living root bridge which has fallen, and was directly replaced by a steel wire bridge. Here, roots from the trees that made up the original living structure are being trained across the wires of the new bridge.  The roots from the two trees have been tied together, and so it is not impossible that, one day, the conventional steel bridge could be used to develop a new root bridge at that location.

This slideshow requires JavaScript.

RANGTHYLLIANG/MAWKYRNOT 1: A CASE STUDY

DSCN0126
Rangthylliang/Mawkyrnot 1 as it appeared in 2015.

Rangthylliang/Mawkyrnot 1 is a large root bridge, which, though part of it appears to be old and well established, has nonetheless been developed extensively in the last few years by a local tourism society. Examples of all four of the training methods listed above are present at this bridge, which allows it to serve as a sort of “showcase” for all of the different ways in which living architecture can be generated.

DSCN0128
A friend poses on the walkway of Rangthylliang/Mawkyrnot 1 as it appeared in 2015. The walkway was then made mostly from bamboo, with one large ficus elastica root running under it.
IMG_2728
As of 2016, the bridge had been modified. Here, you can see many roots running along the structure, several of which had been placed not long before this picture was taken.
IMG_2738
This is a close up of the walkway as it appeared in 2016. Given its thickness, it seems that the large root in the center of the photo was growing across the stream (visible to the left of the picture) for a long time. Note the strands that have been guided across the structure by hand.
IMG_2726
This is the oldest and most well-established part of the living root bridge. Note all of the young strands that have been directed along the bridge with a minimal use of scaffolding.
IMG_2737
Here, some young roots are being left to develop on their own, while one is being run through an Areca Palm trunk. On this particular living root bridge, the Areca Palms that are being used to guide the young roots are also being employed as hand rails.
IMG_2751
While its use is limited, the bridge is also being developed with the help of conventional elements such as steel wire and concrete. Note also the use of bamboo and wood in the scaffolding behind the concrete post.
IMG_2746
Rangthylliang/Mawkyrnot 1. Note the thin roots coming in from the right side of this photo which have been tied onto the structure.

CONCLUSION

While it goes without saying that the ways in which living root bridges are created deserve attention from academics in a variety of fields, it is also important to remember that the people who made them did so without what we would call scientific or engineering expertise. There were no blue prints, and the structures were not planned by professional architects, but by agriculturalists who had to solve a very basic problem.

In a way, I feel this makes the bridges all the more exceptional, in that they are instances of functional architecture that have often seen hundreds of years of service, are in some cases stronger now than ever before, are objects of incredible aesthetic value, and yet they are products of, for lack of a better term, “amateur” architects. What this means is that the basic idea of a living root bridge, despite seeming so unusual and ingenious, is nonetheless something that could be easily transplanted to other contexts. Various kinds of banyan trees can grow in many different environments, from urban areas in Bangladesh, to parts of southern Florida, to indoor gardens anywhere in the world.