Notes from a Summer Cottage

by Nina Burton

  When, at last, attention was paid to Mendel’s theories, genetics became a branch of science all of its own, although mysteries remained. How could the great, messy diversity of life come out of such well-organised genes? This problem would be investigated by a different person with a different plant.

  Barbara McClintock was born just after the 20th century dawned and Mendel’s laws became widely known. She, too, had to choose between having children of her own or researching about the heredity of offsprings, for women were dismissed from university when they married. Then again, McClintock hardly had time for a family. She spent 16 hours a day on her research, splitting that time between the laboratory and the fields where she grew maize. To her, maize plants were more than just a research material. She was their Cupid, hurrying from male flowers to female flowers to fertilise them before the wind could beat her to it. Moving through the field, she nearly disappeared, because despite her nickname ‘Big Mac’ she was shorter than all the plants. When she looked at the maize cells under her microscope she also felt like disappearing – but in a different way. The work was so absorbing that she almost became one with what she saw, and her attentive gaze resulted in the discovery of more details than others had discerned.

  In this micro-world, she was entertaining big questions about inheritance and change. In Mendel’s mathematical tables, genes looked like neatly strung pearl necklaces, but her own results showed something wilder, more random. Some genes jumped around in incomprehensible ways.

  Regular patterns and irregular ones obey different sets of rules, and accordingly they must, to some extent, be understood from different perspectives. McClintock was so attentive to this fact that at last she managed to follow the jumping genes that can transform an inherited trait. But her contributions would receive just as little attention as Mendel’s tables once had. People still didn’t believe that plants could tell us anything about ourselves. Only under the electron microscopes of the 1970s would other researchers see what she had argued some thirty years earlier. Fragments of chromosomes could move around. This explained the jumble of variations in all species and eventually earned her a Nobel Prize.

  By then, her research had also contributed to cultural history. For ten thousand years, maize had accompanied the indigenous people of present-day Latin America, and the time-markers she found in its chromosomes could be compared to the way indigenous societies succeeded one another. Thus, the plant cells under her microscope not only mapped the winding roads of heredity – they also showed the cultural history of a continent.

  After all, it seemed rather logical that plants provided the explanation for the inheritance of life, as depicted in the form of family trees. What’s more, behind them all stands a world tree with roots all over the Earth. It’s found in the mythology of Polynesians, the Yakut of Siberia and the Oglala Sioux, as well as in the Upanishad texts of India. The Babylonians even had two trees: the Tree of Knowledge and the Tree of Life, which were later adopted by Jews and Christians.

  Everyone agreed that there was knowledge to be gained from the branches of a tree. Buddha found nirvana under an Indian bodhi tree, and Zeus was said to answer life’s questions by way of the wind’s rustling in the sacred oaks at Dodona. The messages of more northerly oaks were interpreted by learned Druids, while Vikings communed with their gods in a more brutal fashion in sacrificial groves.

  The world tree is described in detail in the Old Norse Edda, where it was called Yggdrasil. It had three roots, each anchored in its own spring. At the first sat the Norns, who spun, plied or cut the thread of life. They were comparable to the gods of creation, preservation and destruction in the Upanishads. The second root of Yggdrasil was nourished by the well of Mímir, where the waters held a knowledge of everything that had happened and was yet to come. The third root, however, was surrounded by a cold hell, where it was incessantly gnawed by a snake.

  It can be difficult to imagine a world tree with cosmic dimensions, even if you live in it. The people who lived in the middle of Yggdrasil – that is, in Midgard – didn’t even understand that they resided in a tree. It’s true that their forefathers Ask and Embla were said to have been created from pieces of wood, and the runic alphabet that could grasp the events of time had been carved into bark. But the only ones with an overview of Yggdrasil were Odin’s ravens Huginn and Muninn – thought and memory – and they sat in the crown of the tree. With its many branches and runners, it was rather reminiscent of all the synapses of a brain.

  Yggdrasil is said to have been an ash tree, just like the classic Swedish guardian tree, but taxonomy wasn’t so important until Linnaeus got involved. For instance, stags were said to munch on its needles, so one of my author colleagues guessed that Yggdrasil was actually a yew. I myself felt that most indications pointed to its being a birch, for that was the first tree that came to Scandinavia after the Ice Age. Several traits in the description of Yggdrasil were also familiar to me. Its crown and the ground, for instance, were joined by the squirrel Ratatosk, courier between heaven and Earth, just like the squirrel in our own guardian tree. Supposedly stags grazed in the vicinity of the tree, and given the unreliable nature of species identification in ancient times, these could just as easily have been roe deer like those on the property. And certainly Yggdrasil must have had leaves, for bees were said to be tempted by a dripping dew of honey, and that, of course, comes from leaf-feeding aphids. Since one thing can give rise to the next in trees, they contain a multitude of life, from the birds in their branches to the world of their roots, where earth bumblebees, ants, field mice and foxes might live.

  From a scientific standpoint, the image of Yggdrasil as our original home isn’t unreasonable. About 3.2 million years ago, for instance, one of our foremothers fell out of another tree. She could walk somewhat upright if she needed to, but down on the ground she was helpless among swift hyenas and sabre-toothed tigers. The trees provided refuge, and both her strong arms and nimble fingers were well adapted for climbing. The only thing she lacked was the easy physics of a squirrel, for she herself weighed almost forty kilos. Despite her relative heaviness, she had made it twelve metres up in the swaying crown at least once. One might wonder what she was doing up there. She came to be called Lucy by researchers, a reference to the Beatles’ song ‘Lucy in the Sky with Diamonds’. That was about LSD, so maybe there was some narcotic fruit up in the tree? Was Lucy literally high? In any case, she lost her grip on a branch. Because of her weight, she picked up speed as she tumbled down – up to 60 kilometres per hour, which was way too fast. Her injuries indicated that she had time to put out her arms to break her fall, but it was of no use. When the tree no longer held her, the Earth itself became her death.

  Why have trees been given so much significance in mythology? Is it because of old memories? Children, after all, are often tree-climbers. The graceful branches of the birches on the property would hardly support such use, but the way they bent towards the ground formed a leafy sort of hut. And for me, this truly awakened memories of a life in the treetops.

  From the small back garden, an elm managed to make its way up to my tiny Stockholm balcony. Year after year I had monitored its approach, and when the leaves finally reached the balcony it felt like having a tree fort halfway to heaven. The elm was fabulous company. In the spring it brought forth tiny fruits in rounded wings that looked like silver coins; they made a nutty addition to salads. Fittingly enough, some Swedes call them manna. Then the elm leafed out, and every leaf filled with branching veins like the ones in my own hands. And something peculiar happened among them. So that each one could reach for the sun, they arranged themselves very democratically. The crown took on the shape of a ladder, where the lowest leaves grew a little larger than the next ones up – and they also got extra pigment with which to absorb sunlight. The idea was that no branch should be superior to any other.

  Not that the hundreds of thousands of leaves didn’t have their differences. Besides
their staggered placement, they were also formed by a genetic mosaic. Yet they all emerged from the same trunk, and in a sisterly fashion shared the water the tree gave them. On warm days they transpired hundreds of litres of moisture, which benefited others. At night, each leaf fell into a relaxed slumber that made them hang just a bit lower. In the autumn, a few leaves clung to their twigs a little longer than others, and many had time to perform a little dance before they all gathered on the ground. Together they would weigh as much as a fully packed suitcase, and by then they really had travelled for months, with the tree and the Earth, around the sun.

  Unfortunately, my close relationship with the elm came to an end one day. An inspector thought its roots might penetrate the building’s foundation, so it was decided that the tree should come down. I remembered the time back in the 1970s when an entire grassroots movement arose because some of Stockholm’s elms were to make way for a subway entrance. Protesting friends of the elms quickly ensconced themselves in hammocks and tents among the trees, and after a number of dust-ups managed to save them. I was less successful, so my elm was cut down. It turned out to be an unnecessary measure, since the roots had stayed out of the foundation. But among them something more was discovered. The elm’s story wasn’t over yet. The stump put out new shoots, and I was given a cross section of it, where the tree’s history was inscribed.

  I had always seen the elm from above. That was an unusual vantage point in itself, and now I could see it from the inside out as well. Near the middle of the disc was a hole left over from an old rot attack the tree had managed to ward off. Around it arced annual rings that told of the tree’s growth. On the side that had faced the house the rings were smaller than on the other side, where there had been more space and light. Some rings were also thinner and had probably formed during tougher years. When I counted them all, I found that the elm had just turned forty. That’s around the age when elms begin to blossom. They can live for up to five hundred years, if by then their timber has not already been transformed into a beautifully veined table or the bottom of a sailboat.

  What can the insides of a tree tell us? A tree’s life history is taken into account when it’s selected to become a musical instrument. Luthiers building violins prefer to make the top out of spruce that has grown slowly through the changing seasons, preferably with hard winters and sharp mountain winds that encourage the development of strong fibres. The back and ribs, though, should be made of Balkan maple that has grown in a different environment. To create interplay between two types of wood, a sound post transmits vibrations between them; to make sure that no secondary tones interrupt the resonance the proportions must be accurate down to the millimetre. As wood is a living material, the instrument must also be played regularly.

  Is something of the tree’s spirit expressed by violins, guitars and woodwinds? What did the living trees themselves have to say? Their anatomy is entirely different from our own, so they must communicate in other ways. I had discussed the topic with my sister, who was in the habit of talking to a cherry tree in her garden. For my part, I was rather hoping for scientific explanations, and they did in fact begin to emerge.

  Trees are not as lonesome as they appear, for they have entered into a partnership with the largest organisms on Earth – fungi, which can have root systems a kilometre wide. Even in the early history of foliage, they supplied plants with minerals they sucked up from the bedrock, and when they wound their threadlike roots, or hyphae, around the tree’s own roots, both parties benefited. The tree shared the solar energy it received, and in return the fungi gave both nutrition and access to their mycelia. As a result the tree could extend the chemical connection in its interior parts to other trees. They gained a hidden network. Eventually most plants would cooperate with the help of fungi, although those that are purposefully bred seem to have a slightly harder time communicating.

  In any case, it’s clear that trees do care about one another. They recognise their siblings and can adapt themselves in some ways according to the needs of others. If one tree sounds the alarm about an insect attack, its neighbours can quickly mobilise their own defences. Oaks add acrid tannins to their leaves, and those of goat willows get bitter salicylate. Other compounds can lure enemies of the attackers, which then fight off the attack as well. If the damage is natural, however, the tree merely produces healing hormones and doesn’t bother anybody else.

  Naturally, the fact that trees communicate raises questions. Certainly, contact occurs on a molecular level, but behind any mode of communication there must be some sort of consciousness in both parties. No one has ever quite agreed on what consciousness is or where it is situated, yet neurologists and cognition experts had determined that any creature with a nervous system can have subjective experiences. But that was in the case of animals; what about plants?

  This question has popped up at regular intervals ever since ancient times and has been answered in a variety of ways. Democritus viewed trees as upside-down humans with their brains in the ground. Pythagoras suspected that transmigration of the soul included plants and refused to eat beans as a result. Aristotle got hung up on plants’ inability to move around and assigned them an inferior sort of soul.

  And on it went. The so-called panpsychists saw a consciousness in every living thing, while rationalists like Descartes saw every living thing that wasn’t human as a soulless machine; he was influenced by the great invention of the 17th century, the mechanical pendulum that had by then begun to mark time. In the 1700s, the mechanical view of nature was soundly rejected by Rousseau, who, unlike Descartes, spent time in nature and therefore knew it better. Along similar lines, Linnaeus informed the world that plants multiplied and also slept, based on the fact that they changed position during the night. Surely this indicated a certain level of consciousness when they were alert. In the 19th century, Darwin chimed in with arguments against Descartes’ mechanical view of nature. For him, the differences between consciousness in humans and other animals were a matter of degree, and he didn’t find it out of the question that plants, too, could have some sort of intelligence.

  Eventually, technical experiments would enter the discussion. One of them occurred rather by accident, and under fairly strange circumstances. In 1966, CIA interrogation specialist Cleve Backster was supposed to teach police to use a lie detector or polygraph. Among other factors, it registered increased moisture on the skin, and one morning Backster had an idea as he was watering the potted plants in his office. Could the polygraph measure the speed at which the water travelled from roots to leaves? He attached the electrodes to the leaves, but nothing happened. Then his experience as an interrogator kicked in. Could a more aggressive method perhaps provoke a reaction? What if he were to singe the leaves a little bit? The polygraph immediately registered a reading. The alarmed Backster didn’t know what to think. Could plants be sensitive to threats? And if so, what kind of communication system did they have?

  His continued experiments attracted both attention and opposition. Since, like us, plants have a system of veins, it was not unreasonable to suspect they could have an internal system of communication. The idea they could talk to each other, however, was considered absurd. But half a century later, research from agricultural universities confirmed that both wheat and corn plants can transmit small messages to one another through their roots and through the air. Could plants have sensitivity down to a cellular or molecular level? A new area of research arose and was given the name ‘plant neurobiology’.

  The centre of this new discipline was the International Laboratory of Plant Neurobiology in Florence, Italy, where its founder Stefano Mancuso wanted to test a hypothesis. Did plants have a type of swarm intelligence like that of ants?

  It wasn’t an entirely new concept. Maurice Maeterlinck had expressed similar thoughts – alongside his books about bees and ants, he wrote a volume called The Intelligence of Flowers, and it wouldn’t have been much of a reach for him to c
ompare plants to ants. To be sure, Maeterlinck was not a scientist but a lay writer, and intelligence is difficult to define even in a human context. But a hundred years after Maeterlinck’s book was published, Professor Mancuso explored the idea from a more scientific standpoint. To him, intelligence meant the ability to solve the problems presented by life, and technically it could be defined as being flexible in response to outer stimuli. In principle, it could be studied on an electromagnetic or molecular level.

  Mancuso was convinced that different types of intelligence had developed during the course of evolution. One is linked to large, gifted brains like those of humans and was reminiscent of supercomputers. Another type of intelligence, however, is spread out like millions of interconnected computers. Although each individual has a limited capacity, in cooperation they can produce considerable complexity. This is how bees, ants and plants can simultaneously be individuals and parts of a greater whole.

  I thought of my encounters with individual bees and ants, and their advanced societies. Then I compared them to plants. You could tell by looking at the tiny details that made each flower unique that plants, too, were individuals. On the other hand, the word ‘individual’ actually means ‘indivisible’, and you can of course mow grass or take cuttings of geraniums without killing them. Trees can even become stronger when they’re pruned.

  But there is an explanation. Plants are built differently to us. For us, decapitation means instant death, but decapitated insects can live for a little while and plants don’t have heads at all. When you are constantly being eaten by others and lack the ability to escape, it would be fatal to have all your vital parts in the same place, so the senses of plants are spread out. We don’t see them as eyes, noses or mouths, but plants have cells in their leaves that take in light, and their groping roots can feel their way to water and nutrients in the ground. They can even form more roots to absorb what they need. If they sense damaging elements such as lead or cadmium, the roots can retreat.