The Forest Unseen_A Year's Watch in Nature

by David George Haskell

  Unfortunately for the salamanders, the old wet, warm forests that produced salamander diversity also grow large, profitable trees. If these trees are removed in large clear-cuts, the shady leaf litter turns into a sun-beaten crisp, killing all the salamanders. If the clear-cut is lucky enough to be surrounded by mature forest, and if it is left alone for several decades, salamanders will slowly return. But the salamanders do not return to their former abundance, although no one knows why. Perhaps large clear-cuts eliminate genetic fine-tuning from local populations? Logging also removes trees that would have fallen to create moist crevices, nesting holes, and refuges from the sun. The scientific jargon for these life-giving fallen trees is “coarse woody debris,” a term that seems too dismissive for such a life-giving part of the forest’s ecology.

  The salamander in the mandala thrives among the messy tree falls in this small protected patch of old-growth forest, but although clear-cuts are unlikely, the animal is not free from danger. This salamander is tailless, probably the result of an encounter with a mouse, bird, or ringneck snake. When attacked, salamanders thrash their tails to divert the predator. If needed, the tail will break off and undulate violently, providing distraction while the salamander escapes. The blood vessels and muscles at the base of Plethodon tails are specially adapted to clamp shut once the tail is lost. The base of the tail also has weaker skin and is constricted, presumably to help the tail break free without hurting the rest of the body. Evolution has therefore struck two bargains with these animals, both secured with flesh: better mouths bought with lunglessness and longer lives bought with detachable tails. The first deal is irreversible; the second is temporary, erased by the mysterious regenerative power of the tail.

  Plethodon is a shape-shifter, truly a cloud. Its courtship and parenting defy our haughty categories, its lungs were traded for stronger jaws, its body parts are detachable, and it is paradoxically moisture loving yet never enters bodies of water. And, like all clouds, it is vulnerable to strong winds.

  March 13th—Hepatica

  The temperature has been warm all week, giving us an unseasonable but welcome foretaste of May. The first spring wildflowers have sensed the change and have pressed up from below the litter, causing the formerly smooth mat of dead leaves to buckle as the stems and buds of flowers elbow through.

  I shed my shoes for the first part of my walk to the mandala, treading barefoot on the worn public foot trail, feeling the ground’s mild warmth. Winter’s sharpness is gone. As I walk in the gray predawn light, birds are in full song. Phoebes rasp from the rocky bluff, accompanied by titmice whistling from low branches and woodpeckers cackling from large trees below the trail. Aboveground and below, the season has turned.

  At the mandala, I find that one flower bud, a Hepatica, has finally pierced the litter, standing on a finger-high stem. A week ago, the bud was a thin claw, encased in silver fuzz. Slowly, the claw filled out, fattening and elongating as the air warmed. This morning, the bud’s stem is shaped like an elegant question mark, still covered in down, with the tightly closed flower suspended at the tip of the curve. The flower points demurely down, its sepals closed against nighttime raiders of pollen.

  The flower cracks open an hour after first light. The three sepals spread, revealing the edges of three more inside. The sepals are flushed with purple and, although Hepatica lacks true petals, these sepals have the shape and function of petals, protecting the flower at night and attracting insects by day. The flower’s opening motion is too slow for my eyes to perceive directly. Only by looking away then returning my gaze can I see the change. I try to still my breathing, slowing to flower-speed, but my brain races too fast, and the slow, graceful motion eludes me.

  Another hour passes and the stem straightens; the question mark turns into an exclamation point. The sepals are spread wide now, shining rich purple at the world, inviting bees to investigate the untidy mop of anthers at their center. One more hour and the exclamation point is written in a hurried hand, bent backward a little, lifting the flower’s face directly at me. This is the mandala’s first bloom of the year. The lively skyward arch of the flower’s stem seems a fitting gesture of springtime release and celebration.

  The flower’s name, Hepatica, has a long history, one that reaches back to Western Europe where a close relative of the same name has been used in herbal medicine for at least two thousand years. Both the scientific name and the common name, liverleaf, refer to the plant’s purported medicinal qualities, suggested by the three-lobed liverlike shape of the leaves.

  Most of the world’s cultures have a habit of extrapolating from the shapes of plants to their medicinal powers and hence to their names. In the Western tradition, this habit was codified into a theological system by an unlikely scholar. In 1600, a German cobbler, Jakob Böhme, experienced a stunning vision of God’s relationship to creation. The heart-ripping magnitude and power of this revelation tore him away from his shoe-making trade and thrust a quill into his hand. Out flowed a book, a stream of words attempting to communicate the massive wordless vision. Böhme believed that God’s purpose for His creation was signed into the forms of worldly things. Metaphysics was scrawled into flesh. He wrote, “Every thing is marked externally with that which it is internally and essentially… [and] represents that for what it may be useful and good.” Mortal, imperfect humans could therefore deduce purpose from the outward appearance of the world and could see the thoughts of the creator in the shapes, colors, and habits of His creation.

  Böhme’s work caused his expulsion from his hometown, Görlitz. The church and the city council would not tolerate unauthorized mystical experiences. Shoemakers, they felt, should stick to cutting leather and leave visions to the well-read and the well-bred. Later, he was allowed to return on the condition that he keep his quill away from paper. He tried and failed, the vision’s power pushing him on to Prague, where he continued his theological essays.

  Böhme’s ideas did not become widely known until botanical physicians learned of his work. His doctrine helped their trade by providing a theological cabinet in which to store their herbal remedies. Many physicians already used the external forms of plants as mnemonics with which to remember their medicinal functions: the scarlet juice of bloodroot for disorders of the blood, toothwort’s indented leaves and white petals for toothache, coiled roots of snakeroot for snakebite, and dozens more. Now, the healers had a theory with which to organize and justify their practices. The shape, color, and growth of plants indicated their divine healing purpose. The showy, scented blossoms of the apple tree were intended to heal disorders of fertility and complexion; red, peppery plants were stamped with the sign of blood and anger, and so could be used to stimulate the circulation or the spirit. The Hepatica’s three-lobed purple leaves bore the liver’s mark.

  The use of external marks to deduce and remember the medicinal function of chemicals inside plants became known as the Doctrine of Signatures. The idea spread across Europe and attracted the attention of the scientific elite. They tried to haul the herbalists’ doctrine out of folklore and into the then modern science of astrology. The signature in each plant, they claimed, reflected God’s purpose, but it did so through the complex cosmology of the planets, moon, and sun. The apple blossom was governed by Venus, hence its beauty and its healing powers. Jupiter governed all hepatic plants, and Mars ruled the warlike peppers. Correct diagnosis and treatment therefore required that a qualified scientist cast a horoscope and create a remedy incorporating his extensive, expensive knowledge of the celestial spheres and their influence on both plants and the human body. The scientific establishment railed against the country quackery of the simpleminded botanists while expropriating the quacks’ remedies for use in an updated astrological medicine.

  This tension between the medical establishment and the quacks continues, of course. The astrological Doctrine of Signatures now finds itself out of favor. Our physicians no longer believe that God left providential medicinal hints in the shapes of l
eaves and in the arrangement of the stars. We should not, however, be too quick to dismiss the Doctrine of Signatures as a trifling superstition. As a method of cultural transmission of medical knowledge, the doctrine was a powerful organizing device, richer and perhaps more coherent than the mnemonics used by modern physicians to navigate their large stores of knowledge. The method gave healers, most of whom could not read, linguistic cues to connect patients’ symptoms with the sometimes arcane details of botanical identification and medical knowledge. The Doctrine of Signatures persisted for so many years not because our ancestors were simpleminded but because it was so useful.

  Hepatica’s name reveals our culture’s propensity for naming plants after their uses. This method of naming helps us to remember humanity’s dependence on plants for medicines and foods. But utilitarian names can also stand in the way of a full experience of nature. For example, our nomenclature has its teleology wrong. Hepatica exists not to serve us but to live out its own story, one that began in the forests of Europe and North America millions of years before humans came to be. Likewise, our naming imposes tidy categories on nature. These may not reflect life’s complicated genealogies and reproductive exchanges. Modern genetics suggests that boundaries in nature are often more permeable than we suppose when we name “separate” species.

  On this bright morning in early spring, the Hepatica’s confident welcome of the first warm sun and flying bees reminds me that the mandala exists independent of human doctrines. Like all people, I am culture-bound, so I only partly see the flower; the rest of my field of vision is occupied by centuries of human words.

  March 13th—Snails

  The mandala is a molluskan Serengeti. Herds of coiled grazers move across the open savanna of lichens and mosses. The largest snails travel alone, plying the crazy angled surfaces of the leaf litter, leaving the mossy hillsides for the nimble youngsters. I lie down on my belly and creep up on a large snail that sits at the edge of the mandala. I lift the hand lens to my eye and shuffle closer.

  Through the lens, the snail’s head fills my field of vision—a magnificent sculpture of black glass. Patches of silver decorate the shining skin, and small grooves run across and down the animal’s back. My movements cause mild alarm; the snail withdraws its tentacles and hunches back into the shell. I hold my breath and the snail relaxes. Two small whiskers poke their way out of the chin, waving in the air before reaching down and touching the rock. These rubbery feelers move like fingers reading Braille, touching lightly, skimming meaning from the sandstone script. Several minutes later a second pair of tentacles launches out from the crown of the snail’s head. They reach upward, each with a milky eye at its tip, and wave at the tree canopy above. My own eye bulges at the snail through the lens, but this monstrous globe seems to be of little concern to the snail, which extends its eyestalks farther. These fleshy flagpoles now reach wider than the shell and swing wildly from side to side.

  Unlike its relatives the octopi and squid, this land snail has no sophisticated lens and pinhole through which to form crisp images. But just how fuzzy the world appears to a snail is a mystery. Scientists have difficulty asking the snails what they perceive, and this communication problem slows the leading edge of snail vision research. The only experimental success in this area has come from borrowing the tricks of circus trainers and teaching snails to eat or move when they see a signal. So far, these performing gastropods have shown that they can detect small black dots on a white test card. They can also distinguish between gray and checkered cards. As far as I know, no one has yet asked a land snail whether it can see color, motion, or a flaming hoop.

  These experiments are fascinating, but they leave aside a larger question: what is a snail “seeing”? Do snails see as we do, with images of checkered cards appearing in their gastropod minds? Do they experience private displays of light and dark, processed by tangles of nerves into decisions, preferences, and meaning? The human body and the snail body are made from the same wet pieces of carbon and clay, so if consciousness grows out of this neurological soil, on what grounds do we deny the snail its mental images? No doubt what it sees is radically different, an avant-garde movie of strange camera angles and lurching forms, but if the human cinema is caused by nerves, we have to allow for the startling possibility that the snails have a similar experience. But our culture’s preferred story is that the snail movie plays to an empty house. Indeed, the theater has no screen. The snail has no internal subjective experience, we claim. Light from the eye’s projector merely stimulates the snail’s ductwork and wiring, causing the hollow theater to move, eat, mate, and keep up the appearance of life.

  The snail’s head explodes, ending my speculations. The black dome is split by a knot of cloudy flesh. The knot pushes out, forward, then the snail turns to face me. The tentacles form an X, radiating away from the bubbling, doughy protrusion at the center. Two glassy lips push out, defining a vertical slit, and the whole apparatus heaves downward, pressing the lips to the ground. I watch, saucer-eyed, as the snail starts to glide over the rock, levitating across a sea of lichen. Tiny beating hairs and ripples of infinitesimally small muscles propel the ebony grazer on its path.

  From my prone position I see the snail pause amid lichen flakes and black fungus spiking from the surface of oak leaves. I peek over the lens and suddenly it is all gone. The change of scale is a wrench into a different world; the fungus is invisible, the snail is a valueless detail in a world dominated by bigger things. I return to the lens world and rediscover the vivid tentacles, the snail’s black-and-silver grace. The hand lens helps me harvest the world’s beauty, throwing my eyes wide open. Layers of delight are hidden by the limitations of everyday human vision.

  My snail vigil ends when the sun breaks out from behind a cloud. The morning’s soft humidity has lifted, and the snail heads toward El Capitan, or a smallish rock, depending on how you see the world. Here the snail touches a tentacle to the rock, then turns its entire head upside down and stretches up. The neck and head rubber-band into a giraffe’s, farther, a little farther, then the chin hits the rock, spreads itself into a pad, and the whole snail lifts up from the ground in a no-handed chin-up. Gravity blinks and the animal flows impossibly upward and continues its journey, upside down, into the rock crevice. I look up, out of the lens world, and the Serengeti has emptied. The grazers have evaporated in the sun.

  March 25th—Spring Ephemerals

  My walk to the mandala has become fraught. Every footstep threatens to squash half a dozen wildflowers, and so I step slowly, trying to pick out a way that does not leave a trail of crushed beauty. The mountainside is heavily peppered with green and white; half the leaf litter’s surface is covered by newly grown leaves and flowers.

  It is hard, though, to concentrate on my feet when the year’s first butterflies and migratory warblers are flying above me. An eastern comma, a rufous butterfly named for the white curl on its hindwing, flicks past my head and lands on a hickory trunk. The warm sun has roused it from its winter hibernation, hidden under a bark flake. A black-throated green warbler and a black-and-white warbler, both recently returned from Central America, sing from the bluff. The forest’s renewed life seems to crowd in on me from all sides, lifting my spirits with its unrestrained vigor.

  At the mandala I find a starburst of white flowers, a hundred blossoms shining out at the world. Spring beauty flowers with pink-streaked white petals grow low to the ground, intermixed with purple Hepatica. A few rue anemones emerge from the mandala’s edge, their nodding white flowers held finger-length above the leaf litter. Toothwort reaches tallest, just above ankle height, holding flowers with long white petals in clusters at the tips of sturdy stalks. Each flower trails a comet’s tail of lush green growth, erupting life from the mat of dead leaves. The contrast with the wintry trees above the mandala is dramatic. Tree buds are barely broken open.

  Spring wildflowers take advantage of the trees’ sluggishness, rushing through their reproduction and growth before
the tree canopy steals life-giving photons. Although the March sun is still low, its rays are strong enough to burn the back of my neck as I sit. We have reached the peak of the year’s cycle of light intensity below the canopy. Winter’s hold is broken with blazing force, unlocking constellations of flowers and a cascade of animal life.

  The plants that festoon the mandala are collectively called spring ephemerals. This name captures their meteoric brilliance in springtime and their rapid fade in the summer sun, but the name belies their secret underground longevity. These plants grow from subterranean storehouses, some of them growing from hidden belowground stems called rhizomes, others emerging from bulbs or tubers. Every year, the plants send up leaves and flowers, then return to covert quiescence. The flowers’ push into the cool spring air is therefore fueled by food stored up from the previous year. Only after the plants have leafed out does photosynthesis boost their balance sheet. This strategy helps them persist in the choked, light-hungry world of the mandala. Some of these stems may be hundreds of years old, having slowly crept across the forest floor by growing a few centimeters of horizontal stem each year. These plants survive on the food gained during a few short weeks of springtime sun.

  Once the ephemerals have unfurled their leaves, they reap sunlight and carbon dioxide at a furious rate. The breathing holes in their leaves, the stomata, are thrown wide open. Leaves are stuffed with enzymes ready to concoct nutritious molecules out of air. These plants are the fast-food junkies of the forest: they eat rapidly, rushing to get through the meal before the trees block out the light. The ephemerals require bright sunlight to sustain this gluttony. Their hyped-up bodies cannot tolerate shade.