Living bridges of rubber and fig trees will have to be built in cities or forests

Ahmedabad, 6 November 2023

The people of Meghalaya, which has the highest rainfall of 40 feet in the whole world, have built thousands of living bridges after years of hard work. Rivers are crossed by tree bridges. Here, cement concrete or steel bridges have failed due to heavy rains. Then living tree bridges are successful. Intensive studies are now underway to bring this technology to cities and forest areas. It can be implemented in cement concrete cities like Surat or forests like Dangs. There is a possibility of making a living bridge from such trees in Saputara.

To reach the river bank in Tirna village of Meghalaya, there is a huge bridge not made of concrete and metal but of fig trees. Which is a mixture of aerial roots in which the roots are interconnected and woven. The bridge is not only a part of the landscape, but it helps support its ecosystem.

The north-eastern Indian state of Meghalaya looms over the plains of Bangladesh, where there are hundreds of such bridges. For centuries, they have helped the local Khasi and Jaintia communities cross monsoon rivers. The ancients were very clever, unable to cross the rivers, they built the Jingqiang Surviving Native Bridge.

Meghalaya is a humid place. This is the place with the highest rainfall in the world. Mawsynram village receives 11,871 mm (39 ft) of rainfall annually. This is enough rainfall to submerge a normal three-storey building in a flood. The nearest Sohra comes in second place with an average of 11,430 mm (37.5 ft). From June to September, monsoon winds blow north from the Bay of Bengal and cross the humid plains of Bangladesh. When these air currents meet the mountainous region of Meghalaya, they open up – and torrential rains begin.

When monsoon rains periodically cut off the remote villages of the Simlih’s ancestors from nearby cities, they used the living aerial roots of the Indian rubber fig tree (Ficus elastica) to bridge flooded rivers.

Researchers consider living root bridges an example of indigenous climate resilience. This concept of architecture can help modern cities better adapt to climate change.

Trees are not only important for crossing rivers but also hold a revered place in Khasi culture.

Such bridges take decades to build. It starts with planting rubber trees. This tree grows in abundance in the tropical region of Meghalaya. Trees planted on well-located river banks develop large strong roots, then, after about a decade, mature trees produce more aerial roots.

These aerial roots have elasticity, and the flexibility to join and grow together to form a stable structure.

For centuries bridge builders have grown aerial roots on bamboo or other wooden scaffolding, which have been transplanted to the shore across the river. Over time, the roots thicken and form branches called daughter roots. Builders attach these roots to each other or to the branches and trunks of the same or other fig trees. They merge through a process called anastomosis. Where branching systems such as leaf vessels, tendrils and aerial roots naturally join together. Woven into a dense frame-like structure. Builders use stones to cover extensions to the original structure. This network of roots matures over time to bear weight; Some bridges can accommodate up to 50 people at a time.

Tree bridges require the collective work of individuals, families or entire villages over generations. These bridges can last for centuries, with some bridges being 600 years old.
Becomes stronger with age. When there is heavy rain, small cement bridges get washed away. Steel bridges rust. But bridges with living roots can withstand rain.

People realized that root bridges were more durable than modern alternatives, and cost next to nothing. So the villagers now repair the root bridges they had previously left in the forest valleys.

Living Bridge Foundation established. Which creates awareness about root bridges, repairs and maintains old bridges and constructs new bridges.

The surviving native bridges of north-east India have become popular tourist attractions. Could inspire European urban architecture.

Professor Ferdinand Ludwig at the Technical University of Munich has been studying bridges for 13 years.
Salvador Lyngdoh is a native of Meghalaya and a scientist at the Indian Biodiversity Institute.
Tree Bridges Humans, bark deer and leopards use root bridges to move from one part of the forest to another.

How the roots are pulled, how they are tied, how they are woven together varies from generation to generation. No bridge looks the same.

Until the British colonial period in the 19th century, the original Khasi inhabitants of Meghalaya had no written script, as the Khasi way of life was transmitted through oral history. This means that there is little documented information about the bridges.

A digital map of the bridge has been prepared. 3D models have been created to document and use the bridges. Recording, surveying and mapping of root bridges

Explanation: Photogrammetry has been used.

Armed with this information, Ludwig’s team began designing a roof for the summer kitchen using a pavilion of trees inspired by a root bridge.

The Khasis have amazing knowledge as they live in nature or weave branches together to make roofs. To keep team trees thin and growing

constant pruning to encourage

Ludwig is learning how to respond to plant growth in Europe. Efforts are being made to understand how we can adapt tree bridges to urban environments.

The double decker root bridge of Meghalaya is now famous, attracting tourists from all over the world.

Instead of viewing trees as passive elements in cities, trees can be used as active infrastructure to extend the ecosystem services provided by trees in the urban context.

Trees can reduce the effect of urban heat islands. Concrete bridges or buildings absorb heat and keep cities warm.

The Khasi community’s bioengineering integrates trees with their surroundings. This can happen in cities.

Apart from being a part of Khasi culture, the root bridge has always brought economic benefits to the community. In the past, a network of bridges connected villages to nearby towns, providing a route for local people to transport and sell betel and broom grass. Today they have also brought tourism economy.

There is a double decker causeway bridge about 3,500 steps below Tirna village. Which connects the two banks of the Umxiang River. When the water level rose, the Khasi villagers built a bridge over the river.

Local people are working to build a triple bridge.

Can be used by farmers to climb structures such as ladders or bridges in forests.

There are hills up and down on the way to the fertile plains of Gujarat. Such bridges can be built where there are rivers. Living native bridges can play a fundamental role in the architecture of cities. Can benefit urban air, soil and wildlife. Gujarat will have to develop this technology for the survival of cities and villages. (translated from Gujarati by Google)