Take a bracing stroll through a park or wood this weekend and you’ll hear the Arctic breeze rippling through the swaying, leafless branches, almost as if the trees are whispering to each other.
A fanciful thought, perhaps. But make no mistake, trees really do communicate.
They share nutrients, exchange warnings, nurture their young, threaten rivals and bequeath legacies, through an incredible network of roots and fungal threads that scientists call the ‘wood-wide web’.
Oscar-winning actress Judi Dench reveals how her 30 year passion for trees
Now this mysterious arboreal internet has acquired a champion in the shape of Dame Judi Dench, who this week revealed herself to be Britain’s foremost celebrity nemophilist (‘one who is fond of woodlands’).
In a new BBC TV documentary, the Oscar-winning actress reveals how her passion for trees is such that over 30 years she has allowed her six-acre Surrey garden to return to woodland, where she plants saplings in remembrance of relatives, friends and fellow thespians who have died. There are trees to mark the passing of actors Natasha Richardson, Robert Hardy and Dame Judi’s late husband, Michael Williams.
While making the programme — Judi Dench, My Passion For Trees — she spent a year working alongside Tony Kirkham, head of the arboretum at the Royal Botanic Gardens, Kew, to learn more about the secret world of woodlands. What she discovered astounded her.
‘When I planted trees in memory of my friends, I always hoped they’d be part of a community — that they would be communicating with each other,’ she said. ‘It’s so reassuring to find out that’s true. My trees are part of an extended family.’
Judi Dench and Tony Kirkham standing in Norbury Park. She spent a year working alongside Tony Kirkham, head of the arboretum at the Royal Botanic Gardens, Kew, to learn more about the secret world of woodlands.
It was in the Nineties that scientists started to realise that trees are not just individuals but active members of a vigorously chattering, mutually supportive society, not only sharing valuable resources with others of their own species but forming networks with all comers to ensure their shared survival.
Communicating via that subterranean wood-wide web — the name was coined by the scientific journal Nature — they are wired together by billions of gossamer-fine, microscopically small tubes called hyphae, like fibre-optic cables that penetrate the earth, weaving through it to connect a whole woodland or forest.
The hyphae are created by specialised fungi that grow around the trees’ roots and enable individual trees up to 60ft apart to network and collaborate with each other, via chemical and electrical impulses, in dazzlingly complex ways.
A spoonful of soil can hold up to seven miles of these coiled tubular threads.
Professor Suzanne Simard, an ecologist at the University of British Columbia, has studied these interactions in detail and uses the relationship between a Douglas fir tree and a birch tree planted next to it to illustrate the mutually beneficial relationship between them.
When the birch was pulled up to give the fir more light, instead of flourishing, the fir started to fail.
Professor Simard established that the trees had developed a support system, using the fungal network to transfer vital nutrients to each other.
In summer, when the birch was in full leaf, shading the young fir, it directed food in the form of carbon, nitrogen and water via the hyphae network to the fir.
Dame Judi Dench revealed herself to be Britain’s foremost celebrity nemophilist (‘one who is fond of woodlands’).
In spring and autumn, the fir returned the favour when the birch had no leaves.
An awed Professor Simard said: ‘It might remind you of a sort of intelligence.’
Other studies indicate something still more astounding: trees acting as ‘mothers’ to saplings that are struggling to grow in the shade beneath high canopies.
The mother trees have been found to feed saplings of all species — yet nepotism is at work in Nature because they give a little more food to saplings of the same species, and most food to saplings that are close relations.
Without these mother trees, attempts to regenerate forests often fail. When a mother tree is felled, the survival rate of seedlings tends to be much reduced.
Trees even seem to leave a sort of ‘will’. When one tree is dying, it may pass on resources to neighbours of different species, feeding them and helping to ensure that the forest community stays diverse and strong. In the same way, ‘sick’ trees are supported by the trees around them.
The wood-wide web also operates an early warning system. A tree under insect attack can alert trees near by to raise a defensive response, perhaps by releasing a chemical into their leaves that will repel the attacker.
She has allowed her six-acre Surrey garden to return to woodland, where she plants saplings in remembrance of relatives, friends and fellow thespians who have died
It has been known for some time that plants communicate above ground in comparable ways, by emitting airborne chemicals known as pheromones. But when such warnings are sent via the wood-wide web they can precisely identify the sender and recipient, say scientists.
It seems trees may use a form of ‘language’ whereby different chemical molecules act as ‘words’, although this has yet to be deciphered (Prince Charles’s chats with plants will remain soliloquies for some time yet).
There is, however, a dark side to the wood-wide web. Trees such as walnuts have been found to unleash the equivalent of cyber-attacks (or ‘allelopathy’, as biologists call it) by releasing a chemical, juglone, which stunts the growth of rival plants near by to promote their own survival.
Other species commit what has been compared to cyber-theft, hijacking the carbon they need to make food by leaching it from the wood-wide web rather than producing their own through photosynthesis.
All in all, our woodlands and forests operate as a society not unlike our own, incorporating good and bad in the struggle to survive and prosper.
In tree-loving Britain, I believe we already understand some of this at a subconscious level.
It seems trees may use a form of ‘language’ whereby different chemical molecules act as ‘words’
We certainly show an unusual national affinity with and affection for our trees. There are three billion of them in the UK — about 47 for each Briton.
And like the ancient Druids, we revere our ancient survivors. England alone boasts a remarkable 3,400 living medieval and Tudor oaks, which is more than the rest of continental Europe put together.
One huge oak, which rose from an acorn at about the time of the battle of Waterloo in 1815, stands proudly at the centre of Dame Judi’s garden.
The actress is not alone in her intuition that trees, in their highly networked wisdom, have the power to act as living memorials to departed loved ones.
Since 1997, when the National Memorial Arboretum was launched in Staffordshire, some 30,000 trees have been planted by mourners as individual commemorations of the personal sacrifices made by members of the Armed Forces and the police, fire brigade and ambulance service.
‘It’s not a cemetery,’ says one of the staff. ‘It’s a place of life where older and younger generations alike can wander and wonder.’
And, as the Mail reported yesterday, council officials in Sheffield are learning that you mess with such memorials at your peril.
Residents are currently fighting plans to uproot trees planted after World War I in the city’s Western Road to mark the sacrifice of men who attended the primary school on the street and who died overseas.
Perhaps the bureaucrats should pay heed to another living treasure — Dame Judi herself. After what she has learnt about trees, she declared: ‘I will never be able to walk so nonchalantly through a woodland ever again.
‘It’s mind-blowing. A forest is a very social place. Everyone is sharing and passing on things to everyone else.
‘My life now is just trees. Trees and champagne.’
It could be worse.