In the extraordinary book, The Overstory, about trees by Richard Powers, a woman leans against a pine listening for its ‘words before words’ and hears it say: ‘Sun and water are questions endlessly worth answering.’ A wiser tree would add ‘roots and relationships.’
If you’ve ever felt the need to whisper in a forest, your intuition not to disturb the trees has a basis in science. The great, leafy creatures around you are in constant, detailed conversation.
You needn’t worry about disturbing them, though. They don’t speak through the air like you do, but through their toes. Spoiler warning: after reading this you’ll never feel the same in a forest.
Beneath every woodland floor is a massive communications network of near-infinite pathways that connect trees and through which they communicate. This biological system allows the forest to behave like a single organism with arboreal intelligence.
For British Colombia forest ecologist Suzanne Simard, this information required nearly 30 years of complex investigation, testing and asking good questions. But when she hit the jackpot, she knew she’d found something big.
‘It was another world where trees act, not as competitors but as co-operators. They communicate, feed and care for each other.
‘It turns out they converse through sharing carbon but also in the language of nitrogen, phosphorus, allele chemicals, hormones, water and defence signals – essentially vital information.’
This takes place through a fibre-optic-like mycorrhizal mat which connects into the root systems of every plant. We see its reproductive organs: mushrooms. Without it most trees could not survive.
A single mat ¬– made of genetically identical cellular clones – could underpin the entire Amazonian or Central African rainforest and is essentially immortal.
Where the fungal web interacts with the root cells, there's a trade of carbon for nutrients. It’s so dense that there can be hundreds of kilometers of filament under a single footstep.
And here’s the really interesting part. Mother trees – the big ones we’re inclined to look up at and go ‘wow’ – support others of their own kind and even other species, but recognize and favour their own children.
They feed their kin with bigger mycorrhizal networks, sending them more carbon and nutrients below ground. They even reduce their own root competition to make elbowroom for their kids.
When mother trees are injured or dying, they direct messages of wisdom to the next generation of seedlings, dispersing their declining nutrients into the young trees gathered around them.
So there you have it: trees talk, forests think and you can be sure they know you’re there.
But wait! That’s not the end of the story. Trees cooperate with much more than other trees. Here’s a tale about an ant, elephants and a tree that whistles.
The tree is an Acacia drepanolobium, commonly known as a whistling thorn for reasons which will become clear in a moment. It's native to East Africa, grows to around six metres tall and has the usual pairs of mean-looking thorns on its branches.
Thorns don't deter elephants. They can turn a woodland into grass savanna in remarkably short time and have the ecological delicacy of bulldozers. But they avoid the whistling thorns like poison chalices.
The reason is that these trees have bulbous spheres at the base of their thorns and dispense sugary nectar from the ends of their leaves. The result is food and housing for several species of stinging ant with Latin names far longer than themselves.
Some of these species bore holes in the spheres, chuck out the contents and settle in. When the wind blows across the entrances, the spheres whistle like flutes.
If an unwary animal attempts to browse off a whistling thorn, the ants attack with singular ferocity.
There's an inverse proportion between an elephant's size and strength and the sensitivity of the inside of its trunk. Once bitten, as they say, twice shy. The same browsing sensitivity goes for giraffes and other herbivores.
To test whether the ants were truly deterring elephants, University of Florida biologist Todd Palmer and University of Wyoming ecologist Jacob Goheen fed some young orphaned Kenyan elephants branches from whistling-thorn trees, as well as from another acacias. When there were no ants on the branches, the elephants were just as likely to eat Acacia drepanolobium as they were their usual tree food. But when the branches held ants, the elephants avoided them.
The mutualistic relationship, however, is more complex than just housing ants. If the Acacia drepanolobium could be said to have a preference, it would be for the Crematogaster nigriceps ant. And if the nigriceps could be said to have a plan, it would (and does) allow occasional herbivore browsing. This is because a bit of plucking stimulates leaf growth which increases the supply of nectar.
However, if one of the other acacia ant species such as C. sjostedti takes over a tree, its preference is not for the bulbs but holes drilled by stem-boring long-horned beetles and – in ways not yet understood – it attracts them. They eventually weaken a tree and can kill it.
To prevent this, if a tree leans out too far in the direction of another, the nigriceps prune the twigs so there's no contact, avoiding a possible invasion. Too greater variation in the balance between tree, ant and elephant would cause hardship for all three.
There's no need to remind you that, while an elephant's brain is larger than ours, a tree doesn't have one and an ant's is smaller than the point of a pin. We're talking about something other than intelligence here and a synecdoche of a creation story far more astounding that those handed down to us from conventional religions.
Every second of every minute of every hour of every day, year, decade, millennium, million and even billions of years, the relationship between every insect, animal, bird, fish, plant, mountain, continent, planet, star and galaxy is in an exquisite ongoing dance of this and every moment of time. Creation is a never-ending story so big, so small, so destructive and constructive, so beautiful and profound that, like the blind men trying to describe an elephant by touching parts of it, we can hardly see it at all.
And the hardest of all is to understand the outrageously vast time it takes for an ant, a tree and an elephant to learn to dance together in mutual harmony on the African savanna.
So it’s worth remembering that beneath every step you take beyond your home or pavement there’s possibly hundreds of kilometres of living filament under your shoe connected to everything else. And so, come to that, are you.
About the Author:
Dr Don Pinnock is an investigative journalist and photographer who, some time back, realised he knew little about the natural world. So he set out to discover it. This took him to five continents – including Antarctica – and resulted in five books on natural history and hundreds of articles. The Last Elephants, published this year with Colin Bell, is his 18th book.
His other books include:
Gang Town, which won the City Press Tafelberg Non-Fiction award,
Writing Left, a biography of the journalist Ruth First.
Voices of liberation
Gangs, Rituals & Rites of passage
Rainmaker, a novel shortlisted for the 2009 European Union Literary Award.
Just add dust,
Loveletters to Africa,
Blue Ice: Travels in Antarctica,
The Woman who Lived in a Tree and Other Perfect Strangers.
Wild as it Gets,
He has degrees in criminology, political science and African history and is a former editor of Getaway travel magazine.
He was one of the primary drafters of the White Paper that became the Child Justice Act, a trustee of the Chrysalis Academy for high-risk youths, a board member of Wilderness Foundation Africa, a member of the Conservation Action Trust and was the facilitator of the Western Cape Government’s gang strategy roadmap.
His day job is as environmental investigative journalist.