By Gunter Pauli
When in the year 2000 I co-authored and promoted the book “Grow Your Own House” published by VITRA (Germany) I had the opportunity to unveil the beauty, the power, culture, tradition and the economics of bamboo. The book turned into a successful demonstration of the earthquake resistant capacities of this vegetable steel, and the capacity to grow the local economy (in Colombia) where more than 7,000 jobs were created in the aftermath of our academic and technical presentations. This effort to celebrate bamboo, one of the most versatile species of Nature at the World Expo 2000 hosted by Germany, provided an eye-opening experience.
One of the greatest subsequent discoveries was the capacity of bamboo to provide the structure for natural bridges. The Colombian architect Simon Velez, the Indonesian designer Linda Garland and the German wood engineer Jorg Stamm all demonstrated that bamboo could span 40 meters without support. Since I had obtained a German building permit for what at that time was labelled as the largest bamboo structure in the world (an open pavilion), we mastered the science, compression and tensile strength, flexibility and the capacity to dance along the rhythms of the earth. The Science University of Pereira (Colombia) now has an international course on bamboo engineering, with a specialisation in bridge structures.
It is against this background that I need to explain my interest and fascination with the living bridges in North East India. The Indian architect, researcher and explorer Sanjeev Shankar drew my attention to this marvel of a bridge, grown over decades by directing the aerial roots of four Ficus trees to evolve into a robust bridge. There are perhaps as many as one hundred such bridges in the region, and as soon as the British Media (BBC) produced a documentary on it, the world became fascinated by this idea. The bridge stands majestically in a sub-tropical forest near Cherrapunji, that once was known as the wettest place on earth. It connects Riwai and Nohwet village, approximately 30 kilometres from the Bangladeshi border. Thousands of tourists from Assam and Nagaland flock over the weekends to visit this exceptional sight. Visitors are fascinated by the living bridge that stands majestically in this tropical forest.
It took me more than an hour of observations to start to understand the marvel of the underlaying design, the powerful yet flexible roots, the size of a mature bamboo provided a framework structure, and how a maze of smaller roots hold everything together. The diligent work of tensile strength of the upper roots and the lower branches, was complemented with thousands of smaller roots that have been clearly guided by human hands to intertwine around the macro-structure. Then, the lower root system functions with a highly distributed state of compression, able to spread the weight of both the bridge and the 30 to 50 people crossing it with ease offering stability and safety. It was clear that this bridge was not going to collapse anytime soon. Unfortunately, behind the effective yet surprising symbiosis between man and tree, a closer look also provided indications that modern man has no idea how to preserve this creation for future generations, rather the eagerness to see, touch and feel could rapidly lead to the destruction in a few decades (or even years) of a marvel that took more than a hundred years to emerge.
While the bridge was created to be used, and the whole structure is strengthened and alive thanks to its responsible use by walking over it, too many people with as many as thousand visitors a day, many who have the desire to have a close look underneath cause havoc. Do visitors realise that their perspiring hands leave an acid imprint on these roots that during drought causes the immune system of the trees to undergo excessive stresses? While I was only equipped with a GoPro Camera to capture the whole and the details of the bridge, some visitors felt the need to crawl inside the bridge structure, encouraging their children to find the right spot for the epic picture. I am sure that this was not the plan when the villagers decided to open up their treasure and unlock access to the site. Worse, I noted 2 visitors who were clearly on a treasure hunt and broke off a piece of the roots of the bridge as a token to bring home.
In addition to the human induced stress that the trees are suffering, climate change has clearly affected the ability of these living bridges to maintain a healthy living condition. The drought deprives the exposed roots from high humidity levels, urgently needed to preserve this rare case where people learn to work with nature to build cathedral like structures with inter-generational patience to be able to see success. While water flows underneath, a tour through the surrounding forests unveils the lack of humidity. If the village wants to capitalise on the potential revenues from curious visitors, then there will have to be rather much sooner than later a misting system over the bridge in order to maintain the natural dispersing of moisture during the dry season. While this is not difficult to organise, and the capital investments are marginal compared to the capital that has been invested by the hundreds of villagers, and continue to commit, someone needs to decide to get it done.
(Prof Gunter Pauli initiated the Blue Economy project to find 100 of the best nature-inspired technologies that could affect the economies of the world, while sustainably providing basic human needs – potable water, food, jobs, and habitable shelter).
©1999, Luis Guillermo The Las Gavioas seesaw that pumps water while kids play
The entrance fee is a mere 10 rupees. Foreigners who have travelled from far should pay at least ten times as much, and I would argue that a US$ 10 fee is more than right as a small contribution to the community. The arrival of ten foreigners a day offers the funding to install for example a seesaw pumping (see picture below) and moisturising system with one year (US$36,500) without the need to obtain any outside funding or assistance. A strict prohibition should be in place that no one can touch the roots, and anyone damaging whatever the size of impact must be prosecuted with a heavy fine. In addition, the dramatic number of packaging and plastics that are left astray in the 500-meter stretch must be courageously countered. It is not possible that this wonder of the world is patched against a background of plastic waste. Instead of selling packaged food with wasteful wrappings, why is the local community not preparing its delightful, taste and colourful plates.
Meghalaya State in North East India has a few of these marvels and it inspires people from far abound to come and enjoy the view of this exceptional creation. This deserves beyond any doubt UNESCO World Heritage status. It is now time to take the measures required to keep thiese living bridges alive, learn from their exceptional role in tropical communities controlling landslides, providing safe and enduring road infrastructure, and for all of us a chance to learn how through careful observation of natural forces, while understanding the core principles of engineering, we can improve the living conditions, express arts, and enhance the environment. It cannot be that ignorance destroys this unique living structure.
(Prof Gunter Pauli initiated the Blue Economy project to find 100 of the best natureinspired technologies that could affect the economies of the world, while sustainably providing basic human needs – potable water, food, jobs, and habitable shelter).