Judi Dench, tree talk and the Wood Wide Web

Talk the talk: “I shall give up acting and lecture on trees quite soon,” quipped Dench. © BBC

Can trees converse? Scientists have written about their powers of communication. In a new documentary Dame Judi Dench looks at the ways they interact. How much do they share with humans?

“My life now is just trees.”

So says Judi Dench in a new BBC documentary. In Judi Dench: My Passion For Trees, the veteran actress reveals that she has been planting trees in her garden for decades, naming each one after a deceased friend.

Her love for our wooden friends takes her to Kew Gardens, where she spends a year working alongside arborist Tony Kirkham. We see him teach her how trees live, age and — yes — communicate.

Scientists are gradually learning how trees keep in touch through an underground communication network. Fungi attach to tree roots, forming a symbiotic relationship (known as a “mycorrhiza”). Trees give fungi sugars; fungi send water and soil nutrients back. But there is more to it than that.

The fungi spread through the soil, connecting trees. Through these links, trees can transmit chemical messages to each other. If one is attacked by a bug, it can relay a “warning” to others in its network.

There is also evidence that healthy trees can “help” younger or weaker ones by channelling nutrients toward them. “They’ve grown together and they nurture each other,” observes Kirkham. “Trees are like people.”

Experts have coined a name for this network: the Wood Wide Web. Others push the internet analogy further, describing it as a social network. The trees, they say, “talk” to each other.

Nobody has done more to anthropomorphise trees than Peter Wohlleben, a German forester. In his bestselling book The Hidden Life of Trees, Wohlleben sets out his view of how trees interact. They “suckle” their “beloved children”, keep “friends” and guard against enemies. They make decisions, store memories and develop distinct personalities.

For Dench, trees’ powers of communication are a big part of their appeal. “When I planted trees in memory of my friends I always hoped they would be part of a community,” she says. “And now it’s so reassuring to find out it’s true.”

But do trees really “talk”?

Two’s company, tree’s a crowd

Certainly, say some. There’s a lot we still don’t know about how trees (and fungi) interact. That said, studies have shown time and again that they can spread messages to each other. Rather than proud individuals vying for sunlight and nutrients, trees should be seen as a community, constantly conversing and cooperating. They are more like us than we thought.

Don’t get carried away, reply others. Trees do not have brains. They cannot think, let alone talk. There is nothing deliberate about the way they send out their chemicals: their “messages” probably just evolved as a survival mechanism, arming them and their neighbours against predators and diseases. In fact, viewing trees as humans says more about us than them.

You Decide

  1. Is it wrong to cut down trees for wood?
  2. Is it helpful to see trees as having human characteristics?

Activities

  1. Imagine trees could talk to humans. Write down five questions that you would ask them.
  2. Drawing on the information in this story and the articles in Become An Expert, write down three ways in which the Wood Wide Web is like the internet, and three ways in which it is different.

Some People Say...

“Trees are the earth's endless effort to speak to the listening heaven.”

Rabindranath Tagore

What do you think?

Q & A

What do we know?
We have long known that plants exchange information with each other and organisms such as insects. Think of a flower emitting a sweet scent to let bees know that it is ready for pollination. Plants can also exchange “warnings” about, say, a predator through the air. However, messages sent via the fungus network seem to be more precisely targeted to a recipient.
What do we not know?
A lot. We cannot say whether trees (and other plants) “intend” to send each other messages, or even what we mean by a tree’s “intent”. We do not know exactly what role the fungi play in this, and what they get out of it (apart from sugars from the tree). It is unclear to what extent strong trees “help out” weak ones. The science of trees is bewildering — or, as Dench says, “mind blowing”.

Word Watch

Judi Dench: My Passion For Trees
The programme will air at 8pm on Wednesday December 20th on BBC One.
Kew Gardens
A botanical garden in southwest London, it claims to have the largest collection of plants and fungi in the world.
Arborist
Tree specialist.
Symbiotic relationship
When two different species have evolved to live together in an intimate way, they are in symbiosis. If both species benefit, the relationship is “mutualistic”. If only one does, it is “parasitic”.
Mycorrhiza
This difficult word comes from the Greek for “fungus” and “root”.
Warning
Kirkham gives the following example. A caterpillar nibbles an oak leaf. The oak notices and shuts down its photosynthesis, making itself unattractive to the insect. The chemical change is conveyed to other trees in its network, which do the same, in case more caterpillars come.
Anthropomorphise
Characterise a non-human thing as though it is human.
The Hidden Life of Trees
(Harper Collins, 2017; Greystone Books 2016) A bestseller: in Germany, it outsold the pope’s memoirs. But several reviewers criticised it as simplistic and unscientific.

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