It seems a beautiful and universal acknowledgement that trees are good to think with. Everywhere in the world, people have associated tree and thought, idea and forest.

In one of the most fascinating anthropological accounts I’ve ever read, Gerardo Reichel-Dolmatoff wrote breathtaking studies of the thoughtways of the Amazonian people of Colombia. It takes five pages for him even to begin to describe the associations of just one tree for the Tukano people, to show how the ‘bow wood tree’ or jacaranda represents maleness, dominance, aggression and procreative energy. It also suggests a ‘package’ and ‘thunder’, ‘pollination’ and the ‘semen spurt’. So many concepts are held in one tree, says Reichel-Dolmatoff, that it hints at ‘dimensions of mind hardly suspected.’ The Amazon forest itself, according to a Desana elder, ‘is a wide expanse, similar to a perceptive human head.’

Trees have long been associated with knowledge; the Buddha meditated under a tree, and sought wisdom from it. In the early years of Buddhism it was thought that certain spirits of the trees lived in tree trunks and spoke from there. In India, Saddhus have always retreated to the forests for wisdom; the pipal tree signifies universal wisdom and in traditional Indian thought, trees, in their previous lives, were great philosophers. The English language recognizes an association between wisdom and trees: an idea ‘takes root’; a book has ‘leaves’; a small book is a ‘leaflet’; an avid reader is a ‘bookworm’; you ‘branch out’ into a new area of study – even corporate language doffs its cap in the form of

For indigenous people everywhere, nature is an enlargement of your mind and your sense of kin – your social mind. The Malo people of northern Bangladesh used to have a custom of marrying a girl to a tree and a boy to the river, before their marriage to each other. For the Karen in the forests of northern Thailand, the umbilical cord of a baby would be tied to a tree; the spirit of the child dwelt there, and to harm the tree would be to harm the child; the ritual thus intricately linked person to tree.

Forests can also offer political lessons. Indian poet Rabindranath Tagore identified democratic pluralism and an ecological culture as the distinctiveness of Indian civilization. ‘From the forests, we learnt democracy,’ says Vandana Shiva: ‘that every species has its place.’ Black Elk of the Lakota people saw trees as having rights equal to people, referring to them as the ‘standing peoples, in whom the winged ones built their lodges.’

In the Amazon, there is telluric thought, sunk deep in the earth, a wild way of knowing so utterly different from the West, that while we use the term ‘vegetable’ for a comatose mind, and ‘vegging out’ as a slang term for mindless laziness, in the Amazon the wisest men and women are called vegetalistas; plant experts steeped in plant knowledge. But there’s more – people don’t just learn about plants, they learn from certain plants called ‘plant teachers’ or ‘doctores’ which teach people medicine.

When I was writing my book on wildness, I began by staying with Amazonian shamans who used ayahuasca, considered one of the greatest of these plant teachers, shamans who believed there knowledge came from the song of the plant. And they certainly knew what they were doing: I had arrived sick with months of depression, yet after a few days – and a few extraordinary ayahuasca nights – it was gone.

But the Western way of knowing too easily scorns any way of knowing from animal, plant or tree. Socrates, pithily summing up an entire way of thinking, said: ‘I’m a lover of learning, and trees and open country won’t teach me anything, whereas men in town do.’ The Dominant Culture has long operated an intellectual apartheid, arrogantly certain that its own expertise is the only knowledge worth the name. In the days of empire, that single way of knowing invaded the wild world and as it did so boasted that it was an age of ‘discovery’ and an expansion of the ‘known’ world, the false claims of European history that knowledge increased in that era. It did not. The truth was the opposite. For, by destroying forests and human cultures, there was in fact a net reduction in the world’s knowledge. In the Amazon, the assault against nature is an assault against culture, hundreds of tribal cultures.

So kill pity. Crack down on kindness. Pour mercury over metaphor. Burn their books, hack down their languages and axe their philosophies. Tip Agent Orange into the eyes of a forest Picasso. Tie a Shakespeare’s hands behind his back – with razorwire. Break Nureyev’s ankles, stamp on Fonteyn’s feet. Crack Joyce’s head against a wall until the words whimper and fail him. Daub graffiti over an El Greco. Bulldoze the sculptures of Rodin. Burn the entire Oxford English Dictionary. Slash every copy of Dylan Thomas. Napalm the Berlin Philharmonic.

But beyond indignation, beyond anger, there is a terrible and infinite sadness: sadness to the treeless and gaunt horizon for the end of a whole way of knowing, a wild epistemology, knowledge gained through dream and song, songlines and shapeshifting. Native American Black Elk was born in 1863 (in the Moon of the Popping Trees in the Winter when the Four Crows were Killed). When he was nine he had a dream, a vision of being taken to the sky world where he saw the wild animals of the Plains all dancing. At the heart of the dream was a vision of the end of the Plains way of life and a dream of the end of dreaming itself. After the massacre at Wounded Knee, Black Elk said: ‘I did not know then how much was ended … now … I can see that something else died there in the bloody mud, and was buried in the blizzard. A people’s dream died there. It was a beautiful dream … There is no center any longer, and the sacred tree is dead.’

But beyond, again, beyond sadness, beyond tragedy, you can still smell it, this ancient knowledge, philosophy older than any history; they have survived, these trees, somehow, and uncertainly, but there still are forests, suggesting, prompting, speaking, a riot of language in irrepressible gusto, life growling, flowering, leafing, hooting, wriggling and budding, flickering in a forest fiesta of verdant and noisy verbs, the forest is chattering with language, a whole universe laughing with life.