Can living fig-tree bridges save lives in a changing climate?

By AditiVerma2193 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

In 1841, a young Scotsman called Henry Yule was exploring the Khasi Hills of north-east India when he came upon something no other European had ever reported. There, in that challenging landscape of thick rainforest and perilous gorges, was a most extraordinary structure — a living bridge formed from the roots of a gnarly old fig tree.

The tree’s roots had somehow reached more than 20 metres across a river and taken hold on the far side. Over time, they had thickened and interwoven to form a walkway, onto which Yule now had to step. One of the roots, which in places was thicker than his thigh, provided a handrail. Side roots had descended from it and merged into the walkway, making the whole structure strong and secure. Yule could cross with confidence.

The bridge was no miracle. Long before, human hands had guided the tree’s roots across the river, training them into a shape that could promise safe passage. Yule had assumed the bridge to be “unique, perhaps half accidental”, but he soon saw several more. Their architects were local Khasi people, whose attitudes towards time, the environment and their unborn descendants we are sorely lacking in our fast-warming world.

Fig tree bridge. Credit: Laurence Mitchell (https://eastofelveden.wordpress.com/2011/03/06/crossing-the-bridge/)

The Khasi Hills are in Meghalaya, an Indian state whose name means ‘land of the clouds’. The clouds cry often on this land, for nowhere else on Earth must people endure such heavy rainfall. Twelve metres of it falls in a typical year. After monsoon rains, the region’s rivers rise. The rush of water racing downstream renders steep gorges impassable, isolating villages and endangering lives. Yet people have lived in the Khasi Hills for at least 3200 years. For generations, they have overcome this extreme environment by harnessing the strong yet pliant roots of Ficus elastica, a fig species best known as the Indian rubber tree.

Fig roots are exceptional. They grow fast, long and strong. They can even rip apart bare lava and concrete. In many fig species, including Ficus elastica, the roots aren’t all underground. These figs produce aerial roots that flow down their trunks and drop from their branches. Their roots can merge and split and merge again, forming strong, mesh-like structures. Long ago, the Khasi people worked out how to get such fig roots to do their bidding.

It’s a practice still alive today. The Khasi and neighbouring Jaintia peoples have shaped fig roots into living ladders, whose rungs ease journeys up steep slopes. They have woven the roots into nets that hold banks of earth in place, preventing landslides and soil erosion. They have even forced fig roots to form a platform, from which to watch football games. But the masterworks of Khasi architecture are their bridges. Most — like one Yule sketched, below — form from the roots of two fig trees, one on either side of a river. The longest spans more than 50 metres, the oldest an estimated 500 years.

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Building these bridges involves first guiding slender fig roots through hollow trunks of betel palms, which support, nourish and protect the roots as they lengthen. Once the fig roots are long and strong, the bridge builders bind them to those of the opposing tree or embed them in the ground on the far side of the river. They shape secondary roots that grow from these mainstays into a net that will form a walkway. They use stones and soil to plug any gaps then wait for the roots to thicken and hold everything in place.

It can take 15-30 years before the bridge is strong enough to use. But in Khasi time this is an eye-blink. The Khasi people are investors in the future. People living there today benefit from the ingenuity and foresight of their ancestors and today’s bridge builders bequeath security to future generations. The fig tree bridges don’t only make commerce and romance possible between otherwise isolated villages. They also save lives. As the climate changes, this ancient approach to bioengineering has never been more relevant.

Meghalaya was already the wettest place in the world when Henry Yule explored its forested hills in 1841. Back then, the atmospheric concentration of carbon dioxide was 283 parts per million. Today it is more than 400. More carbon means warmer air, and as warmer air carries more moisture, this means more rain. The state government’s climate change action plan says rainfall has increased in most districts of Meghalaya in the past century, with the highest increase in the West Khasi Hills. It warns that as temperatures continue to rise, so will rainfall and the risk of floods and landslides.

To architect Sanjeev Shankar, these threats call for renewed attention to living bridges. In a research paper he presented in 2015, he warned that they are being replaced by “inappropriate solutions”. Quick-fix bamboo bridges buckle and break – they can’t withstand the monsoon rains. People have died as a result. Modern steel bridges corrode, their cables weaken and snap. And because repairs are rare, these bridges last just 40-50 years compared to hundreds for living bridges.

Shankar says the living fig bridges cost next to nothing and become stronger, more robust and resilient with time and use – unlike expensive, short-lived steel suspension bridges. Indeed, some of the bridges Henry Yule saw in the 1840s are still saving lives today. Shankar urges a revival of fig-tree bridge-building, and even foresees bridge that are strong enough for vehicles to cross.

The only downside is the time it takes the bridges to grow. But Shankar sees potential to blend the old with the new. Having seen how Khasi people have used fig roots to mend steel bridges, he envisages planned hybrid structures — steel bridges that fig trees envelop with their roots and make stronger. Shankar wonders if other fig species could perform this role in other countries, helping people adapt to the changing climate.

The question is, will there be time? It’s a question for us all, as climate change doesn’t respect the short-term thinking that tends to rule our lives. The Khasi people’s approach is instructive. To build living bridges, they invest time and effort knowing they might not personally benefit but that their children surely will. Such foresight, patience and selflessness is rare.

This post was first published by the Thomson Reuters Foundation and is reproduced here with permission.

IMAGE CREDITS: Top (Aditi Verma, via Wikimedia Commons); middle (Laurence Mitchell); bottom (Henry Yule, from Yule, H. (1844). “Notes on the Khasia Hills, and people”. Journal of the Asiatic Society of Bengal. 14 Part 2, Jul-Dec (152): 612–631).

My new book —published in the UK as Ladders to Heaven and in North America as Gods, Wasps and Stranglers tells how fig trees have shaped our world, influenced diverse cultures and can help us restore life to degraded rainforests.

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Why are so many strangler figs home to ghosts and goblins?

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No trees are home to a more motley mix of supernatural creatures than the strangler figs, whose eerie aerial roots are adept at seizing imaginations in their grip. Diverse cultures around the world say these trees shelter angels and fairies, gods and ancestral spirits, ghosts and other malevolent creatures.

There may be a biological basis to some of these beliefs. Strangler figs attract ghostly nocturnal animals such as leathery-winged bats and small primates with big eyes that reflect moonlight. In Indonesia and Malaysia, these trees are often home to small saucer-eyed primates called tarsiers (Tarsius tarsier) whose local names mean ‘spirit animal’ or ‘spirit monkey’.

Other denizens of strangler figs are decidedly less cuddly. In the folklore of the Philippines, they include giant tree demons called kapres, goblin-like duendes and the half-human, half-horse tikbalang.

On the Japanese island of Okinawa, folk tales feature impish red-haired spirits called kijimuna that live inside the hollows of strangler figs. These mischievous sprites love to play tricks on passing people, such as sitting on their chests so they can’t breathe.

In Australia, aboriginal stories warn of an altogether more fearsome fig-dweller, the yara-ma-yha-who. This manlike creature has bulging eyes and a gaping toothless maw. When hungry it will leap out of its fig tree onto an unsuspecting traveller. Its fingers and toes end in flattened discs, through which it sucks the blood of its victims.

These are just a few of the many supernatural beings that people across Africa, Asia, South America and the Pacific have said live in fig trees. As my new book Ladders to Heaven (US title: Gods, Wasps and Stranglers) explains, often these stories coincide with taboos against harming fig trees — in the image above, ghosts assail a Bengali man who made the mistake of chopping a branch from a sacred strangler fig.

Whether ancient people realised it or not, by protecting strangler figs, they were ensuring the survival of many other species of plants and animals upon which they depended. That’s because strangler figs are ecological linchpins. They produce figs year-round, sustaining a rich variety of birds and mammals that disperse the seeds of many other forest species. Without strangler figs many of these animal and plant species would simply go exinct.

So next time you see a strangler fig, fear not. The world would be a scarier place without them.

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Picture credit: Illustration by Warwick Goble from the 1912 illustrated edition of Folk-Tales of Bengal by Lal Behari Dey / Wikimedia Commons. Photo: A famous strangler fig called the Cathedral Fig in Queensland, Australia (James Niland / FlickrCreative Commons).

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The orangutan, the strangler fig and the photographer — a story of entwined lives

Orangutan climbing the pillar root of a strangler fig (Ficus stupenda)

Tim Laman / Wildlife Photographer of the Year

I’m thrilled for Tim Laman, who has just won the 2016 Wildlife Photographer of the Year award for this stunning shot of an orangutan climbing the pillar root of a strangler fig (Ficus stupenda) to feast on ripe figs.

There is a sweet irony to Laman’s winning photo. It was thanks to an image of an orangutan that Laman ever visited Indonesia, where he first became a fig biologist and later developed the skills that would enable him to take photos of life in the rainforest canopy.

Back in 1986, Laman had been at Harvard University studying for a PhD when he saw a poster advertising a research assistant’s job in Indonesian Borneo. The poster featured an image (below) from The Malay Archipelago by Alfred Russel Wallace, Laman’s future hero.

Laman got the job, put his studies on hold and travelled to Borneo, where he fell in love with the rainforest. His life tilted in a new direction. For the next few years, he studied  strangler figs — important plants whose figs feed orangutans and dozens of other wildlife species.

To understand these fascinating plants he had to climb the giant trees on which the stranglers grow. It was up there in the rainforest canopy that Tim found his true vocation — capturing phenomenal images of rare and endangered wildlife. Congratulations Tim!

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Notes:

I’m doubly grateful to Tim Laman. First, for his meticulous research on strangler figs, which helped me during my own doctoral research on these plants. Second, for the help he provided when I was researching my book about fig trees Ladders to Heaven / Gods, Wasps and Stranglers. Laman is the star of Chapter 7.

To see more of Laman’s photos, visit his Facebook and Instagram pages, or his website.

Wildlife Photographer of the Year is developed and produced by the  Natural History Museum, London. For more details of the awards, visit the website.

Full caption for Laman’s winning photo:

Entwined lives by Tim Laman – Winner, Wildlife Photographer of the Year 2016: 
A young male orangutan makes the 30-metre (100-foot) climb up the thickest root of the strangler fig that has entwined itself around a tree emerging high above the canopy. The backdrop is the rich rainforest of the Gunung Palung National Park, in West Kalimantan, one of the few protected orangutan strongholds in Indonesian Borneo. The orangutan has returned to feast on the crop of figs. He has a mental map of the likely fruiting trees in his huge range, and he has already feasted here. Tim knew he would return and, more important, that there was no way to reach the top – no route through the canopy – other than up the tree. But he had to do three days of climbing up and down himself, by rope, to place in position several GoPro cameras that he could trigger remotely to give him a chance of not only a wideangle view of the forest below but also a view of the orangutan’s face from above. This shot was the one he had long visualized, looking down on the orangutan within its forest home. GoPro HERO4 Black; 1/30 sec at f2.8; ISO 231.

 

 

The majesty and mystery of India’s sacred banyan trees

Some 550 years ago, so a story goes, the poet-sage Kabir was on a silt island in India’s Narmada River. He was brushing his teeth with a twig. When he flung his toothbrush to the ground, up sprang a gigantic tree whose crown spread so wide it cast shade over a whole hectare of land. Today Kabir’s tree is one of the biggest plants on the planet. Its true story is no less extraordinary than the myth.

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It is a banyan (Ficus benghalensis), one of hundreds of species of fig trees. No other plants feature in so rich a mix of folklore and faith stories as the figs. And none is as awesome to behold as the banyan. Walk beneath Kabir’s tree’s crown and you will see the illusion of a forest, a tight mass of thousands of trees. But look closer and you will see that everything is connected. There is just one tree. The banyan’s Sanskrit names —nyagrodha, ‘the down-grower’ and bahupada, ‘the one with many feet’— hint at its secrets.

Many years earlier another tree had occupied the spot where Kabir’s banyan grows. That tree’s fate shifted when a bird, or perhaps a bat or monkey, passed by having fed earlier on ripe Ficus benghalensis figs. The animal pooped on the tree and condemned it to a slow death by smothering.

The animal’s droppings had delivered a banyan seed to a moist nook. Within weeks, the fig seed had split open. It sent up a firm stalk with a collar of two tiny green leaves. It sent down tiny roots that hugged the host tree as they stretched earthwards in search of soil. In time these roots would expand and enlace. They would encase the host tree and erase all trace of it.

As the banyan grew, its branches also sent out roots. They dangled like strands of unkempt hair. When they reached the ground these roots grew thick and woody and merged to form what looked like new tree trunks. The massive branches reached ever outwards, sending down yet more and more prop roots. These pillars formed increasingly wide circles around the banyan’s core, enclosing it in nested cloisters.

When British historian Thomas Maurice wrote about Kabir’s banyan in 1794, he said it had more than 350 of these false trunks, each one thicker than an English oak tree, and another 3000 smaller stems. He noted that locals said the tree was 3000 years old, suggesting it existed long before Kabir himself. This raises the possibility that it is the same banyan Alexander the Great and his army encountered on the Narmada River when they arrived in India in 326 BCE.

Alexander’s men were certainly the first Europeans known to have seen a banyan. They were amazed. The vivid descriptions they wrote down would inform Theophrastus, the father of modern botany, back home in Greece. But local people saw banyans as much more than impressive trees. The banyans had long been part of the cultural fabric. More than a thousand years earlier the people of the Indus Valley Civilisation adopted a stylised banyan as a symbol in their script. Later Vedic, Jain and Buddhist and Hindu scriptures and stories mention banyans often.

To bodies, these trees provided shelter, food and medicines to treat dozens of disorders. To minds, they formed bridges to the supernatural. Gods and spirits moved among their leaves and pillar roots. By 500 BCE, Hindu texts described a cosmic ‘world tree’, a banyan that grew upside down with its roots in the heavens. Its trunk and branches reached to Earth to bring blessings to humankind.

The banyan became a potent symbol of fertility, life and resurrection. It features in Hindu stories of the universe’s periodic death and rebirth, when everything that exists dissolves into a ceaseless sea. One story says an ‘undying’ banyan is the only thing to survive the deluge. Another says that to ride the sea’s currents, the god Vishnu assumes the form of a baby, lying on his back on a raft formed of a banyan leaf. With one breath the baby swallows all that surrounds it, taking the turbulent universe into the safety of his stomach before exhaling it into fresh existence.

These symbols of life became agents of death after the British arrived in India and began to use them as gallows to execute rebels who resisted their rule. By the 1850s, there had been multiple occasions when they hanged over a hundred men to death from a single banyan. India restored dignity to these trees when it gained independence and made the banyan its national tree.

While the British knew these trees by name, Alexander’s army would not have heard the word banyan. The name only arose more than a thousand years later when Portuguese visitors to India modified the Gujarati word vaniyan, meaning merchant. They named the tree banyan after the traders who set up their stalls in its shade.

A banyan is a natural meeting place, a vast umbrella of dark green leathery leaves that blocks out the sun or showers of rain. These trees form the centrepiece of many villages. Entire cities have even grown up around these trees. Vadodara in western India is one example. It is thought to derive its name from the Sanskrit word vatodar, meaning ‘in the heart of the banyan tree’. Asia’s oldest stock exchange, the Bombay Stock Exchange, was also born beneath a banyan in Mumbai where stockbrokers would gather in the 1850s.

In cities today, the banyans are curtailed by construction or cut down to make way for roads. But if left in peace, there is little to stop a banyan expanding. The biggest one on record exceeds even Kabir’s tree. It is said to have begun life in 1434 at the spot where a woman called Thimmamma died when she threw herself onto her husband’s funeral pyre. The tree, in Andhra Pradesh, now covers two hectares. Twenty thousand people can shelter beneath its crown.

All this from a seed that is just a couple of millimetres in length. Crack one open with your thumbnail and you won’t find much inside, yet the genetic material within has the power to create a tree vast enough to resemble a small forest. Ancient Hindu sages employed this paradox in a parable, which used the imperceptible power within a banyan seed as a parallel of atman, the invisible essence Hindus say permeates and sustains the universe and all it contains.

The banyan’s power reaches deep into our world. Like all fig species, these trees depend on specific wasps to enter their figs and pollinate the flowers hidden within. A side effect of this relationship is that banyan figs are available all year round. They offer a lifeline to birds, fruit bats, monkeys and other creatures, which in turn disperse the seeds of hundreds of tree species, planting the forests of the future. The banyans truly are trees of life.

This post was first published on 21 September 2016 by Newsweek. It is an edited extract of my new book Ladder to Heaven: How fig trees shaped our history, fed our imaginations and can enrich our future, published by Unbound on 8 September 2016. Chelsea Green Publishing will publish an edition for the United States and Canada in November 2016, with the new title Gods, Wasps and Stranglers.

Photo credit: Chad Husby / Flickr (Creative Commons)

10 things you need to know about banyan trees

The splendid banyan trees I met today in a park in Honolulu, Hawaii prompted me to share some things I learned while researching my new book about how fig trees have shaped our world, influenced culture and can help us protect life on Earth. Here are ten nuggets:

  1. The banyan (Ficus benghalensis) is one of more than 750 species of fig trees, each of which is pollinated only by its own species of tiny wasps that breed only inside the figs of their partner trees.
  2. Banyans are strangler figs. They grow from seeds that land on other trees. The roots they send down smother their hosts and grow into stout, branch-supporting pillars that resemble new tree trunks.
  3. Banyans are the world’s biggest trees in terms of the area they cover. The biggest one alive today is in the Indian state of Andhra Pradesh. It covers 1.9 hectares (4.7 acres) and can shelter 20,000 people.
  4. Banyans are ecological linchpins. They produce vast crops of figs that sustain many species of birds, fruit bats, primates and other creatures, which in turn disperse the seeds of hundreds of other plant species.
  5. The first Europeans to encounter banyan trees were Alexander the Great and his army, who reached India in 326 BCE. The notes they took back to Greece informed Theophrastus, the founder of modern botany, and — ultimately — led 17th-century English poet John Milton to write in Paradise Lost that Adam and Eve made the first clothes from banyan leaves.
  6. Hindus say a banyan tree at Jyotisar is the one Krishna stood beneath when he delivered the sermon of the Bhagavad Gita.
  7. For thousands of years, people have used banyans as sources of medicines. Today in Nepal, people use banyan leaves, bark and roots to treat more than twenty disorders.
  8. Hindu texts written more than 2500 years ago describe a cosmic ‘world tree’, a banyan growing upside-down with its roots in the heavens. Its trunk and branches extend to Earth to bring blessings to humanity.
  9. During India’s struggle for independence from Britain, the British hanged hundreds of rebels to their deaths from banyan trees. Independent India made the banyan its national tree.
  10. Hawaii’s banyans are not native. People who have planted them there include Franklin D. Roosevelt, Richard Nixon, Amelia Earhart and Louis Armstrong.

Across the world, the banyans and many other fig species have embedded themselves in diverse human cultures, thanks to some amazing biology and an 80-million-year-old relationship with their pollinating wasps. As my book shows, these trees influenced the development of our species and can enrich our future too, by helping us to restore damaged rainforests and protect threatened wildlife.  The book is out in the UK on 8 September, called Ladders to Heaven, and in the US and Canada in November with the title Gods, Wasps and Stranglers.

I’ll be writing a narrative article about banyans soon. Meanwhile, I will leave you with some more photos of the banyans I saw this morning. Aloha!

One book. Two titles. Coming soon. Get them while they’re hot.

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Nearly 20 years after I started putting ideas down on paper, my book is finally here. The UK title is Ladders to Heaven. It is available from 8 September 2016 as a hardback or ebook, and can be pre-ordered from Amazon, Unbound, and all good book stores.

Later this year, Chelsea Green Publishing will bring out an edition for the US and Canada, with the new title Gods, Wasps and Stranglers. It is also available to pre-order from Amazon.

If you can’t wait, then I recommend journalist Ben Crair’s article Love the Fig, which The New Yorker published last week. It includes some quotes from me. I was also talking figs last week on BBC Radio 4’s comedy chat show The Museum of Curiosity. You can listen to the show online here until about 15 September.

Lastly, here is a preview of the text for back of the book, and below that a photo of the first batch of books themselves. Go on, you know you want one.

They are trees of life and trees of knowledge. They are wish-fulfillers … rainforest royalty … more precious than gold. They are the fig trees, and they have affected humanity in profound but little-known ways. This book tells their amazing story.

Fig trees fed our pre-human ancestors, influenced diverse cultures and played key roles in the dawn of civilization. They feature in every major religion, starring alongside Adam and Eve, Krishna and Buddha, Jesus and Muhammad. This is no coincidence – fig trees are special. They evolved when giant dinosaurs still roamed and have been shaping our world ever since.

These trees intrigued Aristotle and amazed Alexander the Great. They were instrumental in Kenya’s struggle for independence and helped restore life after Krakatoa’s catastrophic eruption. Egypt’s Pharaohs hoped to meet fig trees in the afterlife and Queen Elizabeth II was asleep in one when she ascended the throne.

And all because 80 million years ago these trees cut a curious deal with some tiny wasps. Thanks to this deal, figs sustain more species of birds and mammals than any other trees, making them vital to rainforests. In a time of falling trees and rising temperatures, their story offers hope.

Ultimately, it’s a story about humanity’s relationship with nature. The story of the fig trees stretches back tens of millions of years, but it is as relevant to our future as it is to our past.

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How fig trees shaped our history, fed our imaginations and can enrich our future

After many years of research, writing, illustrating, re-writing and more re-writing, my book Ladders to Heaven is about to be printed.

The publication date is 8 September 2016, but anyone pre-ordering a copy through Unbound will get their book before it reaches the shops, as soon as it is ready. And if you order by midnight (UK time) on 2 June 2016 you will be listed as a patron in the back of the book.

Here’s a preview of the book’s cover and summary text, and a montage of its 20 illustrations, which are available as prints via Unbound.

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