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GREEN FLUORESCENT PROTEIN

CASCADIA IS A place name that’s poetically accurate, since during the monsoon, water runs everywhere. In early spring we wake up to ominous TV weather icons, black cartoon clouds throbbing out snowflakes and dotted lines of rain. Days of purple skies, as if the sun just couldn’t bring itself to come up. Of double wool and kayaking pullovers and rubber gloves whose fingertips fill with rain. Or, we lift ourselves out of bed to snow-dusted mornings. Frost glitter. Sun flurries and fog rays. The beautiful, confused weather of winter wrestling with spring. As it is in much of Canada, March, on the raincoast, is the month of boomeranging winter.

If you drive an hour west out of Holberg along the rim of Quatsino Sound, eventually you come to the open sea, a landless vista at the edge of the Pacific Rim. When the sky isn’t gray, it’s a powdery blue. Low rollers dash apart on bergs of black rock and then slide down the pebbled beaches. The ocean looks dark and bottomless. At the start of the season we work these western slopes, where the snow melts first.

If we threw down our shovels and began to walk south, we’d cross mountains and fjords and rivers for a hundred miles and eventually we’d arrive at Clayoquot Sound. A lush valley where several thousand people once rallied to save one of the island’s last stands of virgin timber. Greenpeace, the Sierra Club, Midnight Oil, plus a salad of activists, grandmothers, and imported urban ragtags. On the way, we’d come across Red Stripe, a mountain shaved on all sides, from shoreline to peak, by disastrously intensive logging. It now erodes quietly into the ocean. Yet no one has ever waged a war of the woods up here. Perhaps it’s too far to drive down rickety roads. Perhaps the trees aren’t all that pretty.

“Harvesting,” it’s called, as if these old trees were cultivars, sown and tended by human hands, just like hybrid corn.

If this particular mountain were a face, some of us would be toiling away on its forehead, where everything has a funny way of traveling up. Sound, wind, birds. Other planters slip over the brow ridge and down the cheeks, and we hear them cursing and taunting each other.

Hey, fucknuts! Too tired to do your own garbage today?

Oh, honey. You gonna to be okay? Want me to come down there and dry your eyes?

Officially, marijuana is banned at work. Unofficially, it’s like salt in a kitchen. Someone has lit a joint, and the smoke floats up in notes of skunk and moldy grass clippings. We hear snatches of a male baritone singing “Sweet Transvestite” from The Rocky Horror Picture Show. Perhaps we hear others badmouthing us, and we’re surprised to find ourselves bruised. It’s the work that does it to us. The repetition is like psychic sandpaper. We’re too tired to fake the social niceties. We’re a little stonewashed around the heart.

On the road below, Adam unloads seedling boxes from the back of the truck and then stops to blow snot out of one nostril. The diesel engine gurgles. Sweat glistens on the top of his head, where a lean, V-shaped tuft of hair grows. He smokes furiously, flipping tree box after tree box down to the ground while issuing tactical directives into his walkie-talkie. Adam was born in Poland. In another century he’d be a Slavic warlord in fur and jackboots, poring over maps in a tent with snow blowing in through the flaps.

Adam peers over the edge of the road to where Carmen works. He calls down to her. She stoops to plant a tree, ignoring him the way people on buses pretend not to hear by armoring themselves with iPods. She stoops and climbs some more.

Carmen, he calls again, cupping his mouth with his hands. You’ve got to wear your high-viz.

DayGlo orange vests, the kind worn by traffic herders. Requisite bush couture, in case we fall and crack ourselves open, so that a helicopter can find our pieces from the air.

Go fuck yourself, says Carmen. She puts her head down and goes back to work as the single moms do, with an unswerving sense of purpose. Fast and yet slow, at the speed of someone hunting for a set of house keys, something small but vital and lost.

Who knows what this grudge is about? It doesn’t seem to need a reason. We discover vendettas the same way we learn all the gossip: breakups, crushes, rumors of hiring and firing. Information circulates like airborne particles, like microbes passed skin to skin. In the end we know so much about one another and yet sometimes nothing at all.

Back at the ranch, Carmen and Neil have been orbiting around one another. Their romance blossoms at night in the kitchen, over puddles of olive oil and husks of garlic peelings. Huddled chats on the steps with cigarettes and cans of Lucky Lager. Love: we creep up to it with our hands outstretched as if to the heat of a wood stove. What we are expands and contracts like a rubber band, crushing us all together.

THREE AND a half billion years ago, the earth was bathed in a briny soup, and the atmosphere was a hot swamp of greenhouse gases. Life was microbial. Then a new bacterium was born. Its guts were speckled with light-absorbing proteins. This cell could perform a chemical magic that none of the other floating squiggles of the prehistoric seas could. It harnessed sun rays. With this energy, it transformed carbon dioxide into sugar and in the process pumped out oxygen. These rudimentary organisms are still around today, in practically every environment where sunlight and water coexist. Cyanobacteria—blue-green algae, the beginning of all things.

Without this evolutionary game changer our world would look completely different. It might now be filled with unrecognizable organisms that thrive on methane or carbon dioxide. Instead, blue-green algae multiplied and colonized and began to transform the atmosphere, molecule by molecule, oxygenating it with their exhalations. Over time these simple photosynthesizers, with their nitrogen-fixing abilities, enriched the seas. They birthed the air we breathe. They are the prototype for vegetation today. When chlorophyll showed up on the scene, plants began their long path toward world domination, since no kingdom covers the land surface of the planet so completely.

Plants began as rafts of single-celled organisms, clinging to one another on the surface of warm prehistoric seas. These cells joined forces and even crawled inside one another, and eventually they crept onto the land. As their numbers grew, they spread out in a thin horizontal layer until crowding began. And then they started piling up, one atop another, like people standing on each others’ shoulders.

Instead of self-exterminating, they cooperated. The cells on the top did the photosynthesizing. The cells on the bottom provided architecture and delivered nutrients. So began the division of labor, the root-to-shoot relationship that defines vascular plants as we know them today. They developed paper-thin solar panels, both porous and waterproof, as remarkable an evolutionary invention as the human lung. They could tilt and swivel in relation to the sun. Their leaves could channel rainwater to all the advantageous places. They grew stalks and stems to better hoist themselves toward the light and to lift their heads above competitors. This evolutionary rise is reenacted each spring, in every garden and park and untended, weedy corner. A green swell so ubiquitous we take it for granted.

Trees are the ultimate result of this evolutionary reaching. The colossal trees of the Pacific Northwest have developed huge, supportive trunks and broad canopies that waste scarcely a photon. Contrary to popular belief, the upper branches of a rainforest canopy do not intertwine. They overlap, but seldom do they touch. Individual trees grow carefully around one another, their branch tips separated by mere inches. It’s a feat of plant diplomacy millions of years in the making, but nobody really knows precisely how or why this phenomenon, known as crown shyness, occurs.

Conifers, especially, are ancient creatures. Their genetic antecedents arose as long as 300 million years ago. Despite their impressive stature, they’re really quite primitive. They never evolved flowers to attract pollinators or fruit to lure animals who might eat and spread their seeds far afield. Although some conifers, like larches, are deciduous, most are evergreen. A conifer has stuck to its evolutionary guns, like a reptile or a fish. Other trees have acorns or chestnuts or winged whirligigs or seeds with rubbery casings, spiny coatings, or dangling seedpods that can be eaten whole or ground up as spice. Conifer seeds come packed inside cones, but they are mostly no bigger than a grain of rice. Each seed is a blueprint for an organism that may grow ten thousand times as large as its natal package. Another irony of nature: big creatures sprung from the tiniest genetic blueprints. Sturgeon can have roe as big as peas. But a human, with all our intricately complicated machinery, comes from a zygote that’s invisible to the naked eye.

In a nursery, conifer seeds are poked into soil and germinated, watered, and fertilized and sprayed with trademarked chemicals whose names make them sound like engineered rain: Benlate, Rovral, and Captan, Bravo, Echo, and Ambush. Out in nature it’s a different story. A ripe cone spreads its flaps and drops its winged seeds only with the perfect combination of temperature and humidity. Some cones drop and are immediately snatched up by rodents, which machine them with their teeth the way we eat corn on the cob. Most of the seeds surviving these forest critters won’t germinate at all. They’ll lie dormant, woven into the tapestry of the forest floor, awaiting the right season, sometimes in vain, for a century or more. While they bide their time, they may be incinerated in forest fires. Many have no hope at all, because their landing pads are too wet or too dry, not warm enough, or too heavily ensconced in moss. The ones that do sprout may be stunted because of lack of light or crowding or overhead obstruction or heavy competition for nutrients.

If you dig out ten square feet of dirt from an old-growth forest, you might find embedded within it a thousand seeds. Some of these might belong to trees that have long since died out or species that don’t grow anywhere nearby. For a conifer, the odds of survival are exceedingly low. But a tree makes up for it with a carpet-bomb reproductive strategy. A healthy parent can grow thousands of cones, each containing hundreds of seeds. In a bumper year a tree blitzes the ground with potential offspring. A phenomenon called, in the poetry of science, seed rain.

A reproductive method like this is expensively rudimentary, subject to the whims of the wind. It’s one of the reasons why the golden age of conifers has already come and gone. But millions of years ago in our planetary past, conifers dominated. The surface of the earth was composed of one megacontinent, Pangaea. Dinosaurs grazed and stomped the land. Many of the creatures that thrived during this long prehistoric phase would not be recognizable today. Clams, squids, and sharks of the 20,000 Leagues Under the Sea variety. Amphibians and lizards. And all those creepy-crawlies that look like giant cockroaches crossed with centipedes, whose strange shapes we recognize from fossils.

During the Mesozoic, conifers thrived at every latitude from the equator to the northernmost reaches of the globe. New tree species were born, and they diversified and specialized. Most of these genetic families are extinct. The survivors are among the world’s oldest living plants, and many are rare and endangered today. These include the ginkgo tree and sago palms, which are tropical plants that look like a cross between a fern and a palm but are neither. Also the dawn redwood, a relative of the California sequoias, thought to have died out until a small grove was rediscovered in a remote province of China. The fossilized stumps of dawn redwoods have turned up on tundra barrens deep inside the Arctic Circle—a sign of the extensive range that conifers once enjoyed.

With time, conifers met a rising tide of competition from the next generation of evolutionary design—angiosperms, the great planetary flowerers. Angiosperms developed a more sophisticated reproductive apparatus. They grew fruit to attract animal distributors and flowers to lure winged pollinators, and with these mobile partners they edged conifers into extreme environments, higher up the mountainsides and closer to the poles. Today conifers still thrive in these cold marginal zones, while the leafy tropical and temperate angiosperms came to occupy the prime real estate around the belly of the globe.

Pangaea split into two continents, Laurasia to the north and Gondwana to the south. As these two landmasses drifted apart, new species evolved into two parallel lineages. The effects of this genetic quarantine are still visible today in the distribution of modern tree types. Conifers that grow in the southern reaches of Chile, Argentina, and Oceania look nothing at all like those in the Northern Hemisphere, though the species of Russia and Canada are quite similar. Many southern conifers belong to the Araucaria family. An example is the Chilean monkey puzzle tree, whose swooping boughs are said to curve like monkey tails. They have tough, spiky foliage, reminiscent of Stegosaurus plates, perhaps not surprising since these trees are one of the world’s oldest species and are considered living fossils.

Today, the conifer forests of the Northern Hemisphere are dominated by trees in the pine family. Those elegant, slender-leaved specimens we’ve come to associate with Christmas—spruce, fir, hemlock, larch, and pine. Most of these are found in the boreal forest, an expansive sheet of tree cover that runs across the upper strata of North America, Scandinavia, and Russia. Trees from the pine family also find homes in more southerly locales at high elevations, on mountaintops in Yellowstone National Park and in the Appalachians south to Virginia.

There are few living things on Earth as old as the DNA of conifers. Modern evergreens are but vestiges of an ancient heyday, a fact that might contribute to the feeling people get, when they hike through an old-growth forest, that they’re experiencing something majestic and timeless. Conifer genes have survived for a few hundred million years, weathering droughts, infestations, mass extinctions, and wildfires, not to mention ice ages. It’s as if conifers were made to thrive in extremes. In this sense the coniferous forests of the world are heirloom ecosystems, repositories of survivor DNA.

EVERY DAY brings a new mountain to climb. Today I’ve been assigned a steep wedge of the cut that extends from the uppermost road all the way up to the timberline, where the stumps are so distant they look like gray stubble. First, I must climb the cut bank, the scar left behind after the road was carved from the slope. Here I can see the layers of the old forest floor in cross section. On the bottom there is bedrock, above that a horizon of gray-brown mineral dirt, and on top, like cake frosting, a layer of living earth, which comes in shades of cabernet, rust, and ocher, depending on what’s composting inside. Out of this topsoil hang dead roots, spilling like the cords of a circuit box torn from a wall. I’ve got to climb up with my fresh load of trees. I find toeholds on outcroppings of broken rock. I grab fistfuls of roots to haul myself up, and I hope they hold, since the dirt is as loose and slippery as pastry flour.

On a cut block the slash intensifies the closer you come to a road. It’s the nature of the way logs are removed, dragged from every corner by grapples and pulleys and cable skylines to landings where they are loaded onto trucks. Sometimes the ground is piled so high with overturned stumps and cast-off logs that I feel I’m entering a chasm or a maze or a room full to the rafters with broken furniture. Sometimes I walk on logs stacked three and four deep, so my feet never touch the ground. I’ve got to pass through these sections first, when my load is the heaviest. I poke a tree in here and there, but mostly I travel through as quickly as I can.

Eventually the slash thins, and I find islands of life once again, moss and ferns peeking out between the logs. By the time I’ve worked halfway up the slope my quads and calf muscles burn, and I strip off an outer layer of clothing. As I climb it grows colder—the upper soils are chunky with frost for some time after the valley bottoms have warmed. Such small changes create new habitats and subtly varied communities. In this upper stratum the residents have learned to love an extra month in the fog, an extra hour each morning in the lee shade of the mountain.

As I close in on the top I find old snow patches. If the snow is clean I’ll dip my hand in and eat some. Rodents tunnel underneath these melting heaps. Some creatures find their niches in the snow itself. With climate change, cold-loving plants inch up the mountainsides, year by year. Or perhaps their seeds will blow northward, finding purchase in previously inhospitable locales. Animals, too, will creep toward the sky and closer to the poles, searching for the climes of home.

Once, this place—like much of the North American west coast—was impressively forested with Pseudotsuga menziesii, the great Douglas-fir, which is not a fir at all but a species unto itself. A long-lived, mighty tree named after Archibald Menzies, a botanist on Captain George Vancouver’s nautical expeditions who first encountered the tree in Puget Sound. Menzies stepped off a ship in 1791 and found a fir tree so big it would have taken eight people just to encircle it with their arms. In his time Douglas-fir forests grew from the south coast of British Columbia all the way to Mexico. Tree trunks grew with such stoutness that it must have been impossible, quite literally, to see the forest for the trees. It must have appeared that behind every tree there was another one, and another, and that they grew this way, inexhaustibly, forever.

A mature Douglas-fir is a columnar giant. Its trunk looks as if it were made of cement. It has craggy, fireproof bark, which can grow a foot thick or more. An old fir forest looks like pillars supporting the sky. But these soldierly looks conceal vulnerability, for high aloft its soft needles fill the canopy like delicate brushes. Like many conifers Douglas-fir grows but once a year, furiously, for just a few months, pushing out new bracts like fanned fingertips. This fresh growth is so tender it may break off in the first stiff wind. There is an airiness in the upper reaches, a reminder that the tree is ethereal as well as earthbound.

Douglas-firs love sunlight. They like to bury their feet in sand. But they don’t like to share their space with other species, preferring to grow among themselves. They are a little bit prissy but also opportunistic. They wait for devastation, wildfire, and windstorms, and then they grow rampantly and all at once. But only for a few hundred years, since their fate is to be replaced by cedar and hemlock, their patient rainforest successors.

A felled Douglas-fir can yield a one-hundred-foot log that is knot free and perfectly straight grained. The wood has a distinctive salmon hue. It doesn’t warp, is both strong and beautiful, and is therefore prized for structural and decorative uses. It is an economic champion tree—to some, the most important lumber species in the world. That is why Douglas-fir seedlings are always passing through our hands. We dose the land in the hopes that someday there will be many more. An overdose, some would claim, this preferential selection of one species over another. But maybe our manipulation is an inherently human thing, for people have been shaping nature for all of recorded time. Hybridizing peas. Cultivating lawn grass. Breeding dogs and breaking horses. Bringing wild things indoors and then turning them out domesticated.

The biggest Douglas-fir in the world is 242 feet tall. The Red Creek Tree lives on Vancouver Island, near Port Renfrew, but it is less a freak specimen than a dwarf survivor. In the first half of the twentieth century firs that were four hundred feet tall and a thousand years old could easily be found. Families came to visit and to picnic underneath their magnificent crowns.

THE DNA of trees may be very old, but many of today’s forests are relatively new. During the last ice age, plunging temperatures killed off much of the plant life in the Northern Hemisphere. Ecosystems were buried in snow and then plowed under by great accumulations of ice. Glaciers piled up to thicknesses of a mile or more, a mantle so heavy that land surfaces sank below sea level under the weight. As they flowed over the land, these rivers of ice ground down mountains and filled in valleys with scree and sediment. An earth-rending upheaval known as primary succession, wrought by forces on par with volcanic eruptions. And so the largest deforestations the globe has ever experienced were caused not by chain saws but by climate change.

At the height of the Wisconsin glaciation, more than ten thousand years ago, forests retreated into ice-free corners of the North American continent. Plants and animals squeezed into tiny coastal refuges along the Pacific and into unfrozen regions farther south. Ice covered all of Canada, the American Midwest and New England, and even portions of Montana and Washington State. The subglacial fringe, from Pennsylvania to the Pacific Northwest, was tundra and cold steppe. The California coast from San Diego to San Francisco grew a patchwork of cold coniferous woodland. The southeastern corner of the United States, all the way down to the peach- and pecan-growing states, had a landscape similar to that of modern-day Maine.

Once the planet warmed the forests recovered. In the wake of the glaciers, trees edged north from their warmer southern havens. Eventually they recolonized the continent, but they didn’t stop changing after that. Forests are ecosystems in perpetual motion, though their shifts, to the human eye, are imperceptibly small. If it were possible to capture these movements in a thousand years of time-lapse photography, we’d see that forests are always adapting—growing and shrinking, mixing in composition, moistening and drying out. They’re always changing, because nothing on Earth is constant, not the weather, not the climate, not even magnetic north. The Earth’s crust is on the move, always slowly, but sometimes with great upheaval.

In nature there is no such thing as absolute stasis. But if such a state could be said to have existed, a moment of sylvan equipoise, of triumphant postglacial return, it would have occurred between five thousand and eight thousand years ago, when the forests recovered from their frigid setbacks. After the planet had warmed sufficiently, they took on roughly the shape that we recognize today. In this fragile period of maximum expansion, humans had not yet wielded their adzes and axes, not yet begun divesting the world of its forest cloak. If you found yourself at the equator at precisely this moment and began walking north to the Arctic Circle, you would see countless forest landscapes and thousands of kinds of tree.

You might begin this journey in the Amazon rainforest, with its staggering variety of plants and animals. You would walk among endless tropical trees, their flowers heavy with scent. You’d see many kinds of sweet, exotic fruit. You’d see vines and creepers and strangler plants, winding their way up the trunks of tall, smooth trees, parasitizing their superlative architecture. Brazil nut trees and silk cotton trees, murumuru palms and big-leaf mahogany. You’d pass through luxuriant hanging gardens of ferns and orchids and myriad airborne plants dangling their roots in midair. These trees never shed their leaves all at once, since it is balmy all year round. There is no need for winter dormancy. As a result, if you cut down a tree, odds are good it would have no annual rings. In the Amazon you’d sleep among ten thousand tree species. You might never notice the same kind twice.

As you journeyed north you would pass through the tropical rainforests of Central America. And then the temperate montane forests of Mexico. Through the grasslands of Texas into the moist temperate woodlands of the American South. You would travel into a transition zone between warm and cool regions. You’d cross into the varied and beautiful deciduous forests of the United States. They’d contain fewer species than hot, equatorial regions, but you’d still find a cornucopia of types. Oak, elm, beech, and maple. In the autumn you would see the leaves change color, from green to red and yellow, a sign of the remarkable angiosperms at work. They draw out every last bit of chlorophyll and minerals before casting their foliage to the ground. Once the leaves have dropped they begin to break down, providing compost in years to come. And this, too, would have its own aroma.

Around the Canadian border, you would cross the Mason-Dixon line of the tree world, transiting from deciduous to coniferous regions. It is not a line really but a gradient of zonal shifts from broad-leaved to needled forest. You’d see firs. And then a lot of spruce. The great variety of species you experienced in the tropical rainforest reduced to just a handful of hardy, cold-weather types. You’d glimpse quintessentially northern animals: caribou, lynx, bear, moose, and even bison. Chances are you’d spend much of this journey trudging through muskeg, bogs, ponds, and peatlands. For in the north there is water everywhere.

It might begin to snow. As you continued farther north, lakes would ice over. You might notice that black spruce have the meanest, sharpest needles. They’ve got to be tough to resist freezing. You might also notice that conifer boughs are perfectly designed for the weight of frozen precipitation. They catch snow and shed it strategically close by so that come springtime, there will be snowmelt, perfectly positioned for the roots to drink up. These are harsh environments. Summers provide just a few short months of frost-free nights. For much of the year water is locked up in ice.

As you moved north the temperatures would grow colder and the days shorter still. The trees would shrink, becoming more gnarled and dwarfed until some stood no taller than your shoulders. Eventually you would reach a zone of alder and birch shrub. And then you would come out into the clear of the tundra heath, completing your journey through the three great forest belts on Earth.

You may have noticed, walking through jungles, swamps, and pine barrens, that the basic morphology of trees is everywhere the same. Leaves, branches, trunk, roots. An elegant design that is both simple and mind-bendingly complex. On the one hand, you might feel as if you’d passed through an all-connected thing whose infinite sum was much greater than its parts. A global thatch interrupted by grasslands and deserts and lakes but whose reach was so extensive it could be taken as a defining characteristic of Planet Earth. On the other hand, you might take it for granted, like air or water.

Today, only one-third of this original forest cover still exists. Temperate deciduous forests were cut down long ago. There are only a handful of large, ancient timberlands left in the world—the boreal forests of Canada and Russia. In the tropics three areas remain—the Southeast Asian tropical rainforests of Indonesia, Borneo, and Papua New Guinea. The primary forests of Africa are contained largely within the Congo Basin. Last there are the rainforests of the Amazon, ecosystems so richly life giving they are thought to contain one-tenth of all plant and animal species in the world.

TREES MAY be the most obvious thing about a forest, but they are far outnumbered by other organisms. The coniferous ranges of the Pacific Northwest are home to hundreds of different mosses and lichens. In our soggy world, organisms that thrive on moisture and rot do a brisk business. Toadstools rule. There are over a thousand kinds of fungi in every shape and color you can imagine and many more yet to be classified. Some look like horse’s hooves, like albino pinecones or beef tripe, like cocktail umbrellas or undersea coral. Some of them are edible. Wild gourmet mushrooms like chanterelles and pine mushrooms sell for exorbitant amounts per pound. Some mushrooms are hallucinogenic. Poisonous varieties, if ingested, can cause gastrointestinal distress, tingling fingers, unquenchable thirst, floating sensations, delusions of grandeur, and even coma. Some work quickly. They have caused people to fall into chemically induced crazes after just a small nibble. The most deadly kinds cause liver and kidney failure. Some toadstools can kill you slowly, over several days.

Above-ground mushrooms are the fruiting bodies of vast subterranean networks. One such fungus, a honey mushroom, is the biggest organism on Earth. It grows across two thousand acres in the rainforest in Oregon and is thought to be more than 2 ,400 years old.

Despite their homely, blanched looks, humble fungi are among the most important living things in the forest. They’re saprophytes, recyclers of nutrients. But fungi are also the unseen life-support system of the plant world.

The dirt in the forests of the Pacific Northwest is poor in nitrogen, which is a critical nutrient for plants. Tiny, underground fungi sheathe the tree roots. But they lack the ability to photosynthesize. They draw nitrogen from the environment and convert it to a form the tree can digest. In exchange the tree feeds the fungi sugars. Together they grow, turbo-boosted by each other’s secretions. It’s an evolutionary miracle that the conifers have grown to such soaring heights, and they owe their success to this symbiotic relationship.

Often enough, it is an ephemeral association. The embrace of plant roots and fungi forms and disintegrates every year, like a summer camp romance. In the autumn root and fungi tissues dissolve, in turn plumping the soil with organic matter.

Mycorrhizae, these fungi are called. They were discovered little more than a century ago and are still not fully understood today. Some kinds of mycorrhizae even penetrate plant roots and proliferate inside. They are so intertwined with the tree that if you look at them under a microscope you can barely see where one organism ends and the other begins. In an established forest, parent trees dose new seedlings with mycorrhizae, in effect sharing their fertilizer. After a wildfire mice eat truffles and spread fungal spores, re-inoculating the land. Without mycorrhizae, many of the world’s forests would look totally different—they might be grasslands or clumps of dwarf trees. Nature has a gentle way of pairing giants with miniature beings; for example, whales, the largest mammals on Earth, feed on shrimp the size of pinheads.

Interspecies relationships occur everywhere in nature. They are so ubiquitous that we take them for granted. Flowering plants, their roots locked in the ground, depend on the unfettered mobility of animals for wide dissemination—birds, bees, bats, moths, ants, and butterflies are all flower pollinators. These are very old co-evolutionary marriages, millions of years in the making. Sometimes the relationship is monogamous. Yucca and fig trees and many kinds of orchid have exclusive relationships with just one pollinating creature. One-third of the world’s food supply comes into being this way. Without this symbiosis we’d have far fewer things to eat, no apples, plums, or berries. No turnips or pumpkins, no cashews or almonds. We’d have no chocolate or vanilla. No coffee or Coca-Cola. Without pollinated flowers we’d be stuck eating ferns, mushrooms, and algae.

Root-fungi relationships are thought to enhance the growth not only of trees but of most plants everywhere. Some 80 percent of vegetation has relationships with mycorrhizae. Some plants can’t live without them. Only a small percentage can survive without any symbiotic association at all—those vegetables that kids like to hate: cabbages, broccoli, and brussels sprouts. Symbiotic relationships are so crucial to life on Earth that some scientists propose, in a theory called symbiogenesis, that interspecies collaboration is a driving force of evolution. According to this idea, the origin of species isn’t random mutation or competitive selection but reliance and cooperation.

Lichens are simply fungi that have made friends with algae. In the Pacific Northwest they grow on practically anything that doesn’t run or slither or fly—tree bark, rocks, soil, and decaying logs. They dangle from branches like napkins thrown over a waiter’s arm. Some are bright orange, whereas others are coal black. Some look like barnacles and others look like lace. One lichen resembles a toad pelt. They can mimic anything at all—cabbages or dust or Silly String or antlers hanging upside down. Most look faintly evil, like ingredients for witch’s brew. They have poetic names like pimpled kidney, questionable rock-frog, rag (tattered or laundered), and devil’s matchsticks.

Lichens are also extremely sensitive organisms. They are supersponges, absorbing the faintest traces of whatever toxins happen to drift past, from air pollution to radioactivity. Like many forest organisms, they grow with excruciating slowness, a tiny fraction of an inch per year. Methuselah’s beard is a rare and beautiful lichen that looks like long lengths of fluffy white string. Before it died out in Europe, people wound it around their Christmas trees as tinsel. In North America it loves to grow in the arms of an old Douglas-fir tree. In fact, it prefers an old-growth forest to the exclusion of any other habitat. Once these forests are gone, scientists believe, so too will be Methuselah’s beard.

SOME PEOPLE prefer to plant trees with a partner—for the company, the shared snacks, and the subliminal comfort of knowing they won’t be caught alone with a bear or a sprained ankle. Some people say their minds have too much to gnaw on when they work in silence. I met a guy once who said he quit planting trees after two weeks for precisely this reason, the unbearable emptiness of the field.

Some people wear iPods to drown out the solitude, but I don’t mind being alone, if only because I can’t plant trees and talk at the same time. I expend all my brain power thinking about where I’m going to step next and if I’ll waste precious minutes climbing around instead of over. When I arrive, will it make a good spot to put a tree? Most days I carry several species, and every three steps I must choose which one to plant, depending on the composition of the soil. I can tell what the earth has in store by the vegetation that grows on top. My hands know each kind of tree by feel alone.

I’ve got to memorize where I’ve been so that I don’t hit the same spots twice. This is verboten, along with two dozen other planting taboos like J-roots, leaners, air pockets, trees planted deep and shallow, too close and too far apart. Misdemeanors sniffed out by quality control staff, summer interns, or rookie foresters who troll our fields with plot survey cords and measuring tape and quivers of mechanical pencils. Checkers, they are called, and we like them as much as most people like tax auditors—as a necessary, impersonal evil. Maybe they resent us, too. Often they’re paid less than us by a factor of three.

A bundle of trees feels fundamental in my hand, like a loaf of heavy bread. I crack the plastic wrapping and slide out a seedling. It’s a Douglas-fir that looks nearly edible, like a shoot of gourmet salad. But a cultivated tree, for all its organic seemliness, is quite an artificial thing. It’s grown from seed in nursery greenhouses. The seeds come from orchard trees or genetically superior wild specimens. These are harvested by cone pickers. Who are these people? We’re workers at different ends of the assembly line. Our paths never cross.

Today I carry extra pounds of fertilizer, which come packed in paper pouches. Tea bags filled with powdery beads that look like swimming pool chemicals. I prod one into the soil next to every tree. Seedlings often refuse to grow without a shot of artificial nutrients. Native ferns and shrubs, the free-range competition, have an advantage, since they were born in the wild. For a year our trees have been watered and protected and cared for, and they grow lushly, with lots of needles—a biological load they must feed all at once without yet having sprouted new roots. A planted tree is like a transplanted kidney. It must knit itself into its new environment and grow a mycorrhizal sheath. It must learn to drink and eat and get along with its feisty neighbors.

Climbing up, I smell cut wood commingling with dirt and the bitter vegetable fragrance of plants. I pass through aromatic zones that fool my nose. I’ve worked in cut blocks that smell like dill pickles, like wet cinnamon, like mud baked onto a tailpipe. Sometimes I get phantom whiffs that remind me of other places, that plunge me into memory, that make me feel sad or inexplicably happy or a bit of both at the same time. A clear-cut is a protean place. It is both full and empty, depending on the eye of the beholder. It doesn’t smell like any air freshener you can find on a supermarket shelf. No laundry softener or room spray or shampoo wrapped in a leafy, green label with the word glade stamped on the packaging.

My favorite part of a clear-cut, if such a thing is possible, is the very top edge, where the stumps meet the old forest. I will have climbed hard to get there, but usually it’s as clean as a fairway and is a good place to catch my breath. Inside the pillars of the standing forest, the breeze calms. The air is moist and cool. Many of the trunks are marked with lines of spray paint or ribboned with tape—they’ve survived by inches, for now. This is the block boundary, where the ecosystem cleaves in two. The ground is still clothed with a thick layer of moss, sometimes several kinds in various colors. Sword ferns sway. The wind rushes through the canopy. This is the voice, according to local indigenous myth, of Dzunukwa, a witch-spirit who eats misbehaved children but whose blessing brings great wealth. Standing in the drip line of these forest grandfathers I often wonder what it must feel like to be a faller. Trees crash down around these men all day, like dinosaurs falling from the sky.

Some people think a clear-cut is dead and ugly, but I don’t. To me it is heavy with history and ruination and decay, the way a crumbled Doric column tells of extinct civilizations. Branches with chandeliers of trembling, rust-red needles. The corpses of creatures that once lived a dozen stories in the air litter the ground. I find the wrinkly remains of lungwort, which once hung from upper branches. High-flying tree lettuces that perched in the crooks of the canopy. They look not like organisms that lived on mist and tree bark but like something a scuba diver might have plucked from the depths of the sea. I touch them and they turn to mush or to powder, or they crackle into tiny pieces. Perhaps mine is the thinking of scientists who find rat brains fascinating or surgeons who think of sutures as craftwork. A perception of strange beauty that comes from overexposure and the willful overlooking of the obvious.

At this time of year, before the winter is really gone for good, the slash fields are brittle gray, weathered and skeletal as a bone yard, but only when you look at them from afar. Up close and inside there is always something moving between the broken logs and stumps. The dirt is alive. Before the heat of summer the salamanders, frogs, and earthworms are busy sliding in and out of their holes, as if they were renovating. Slugs the size of bananas leave trails of viscous goop. Every five steps I crash through a spider’s handiwork, a sticky veil across my cheeks and eyelashes. Water percolates just beneath the ground surface, like a pulse beating under skin. I open a hole and find water at the bottom. I can even see the current, the slow eddying of this tiny pocket of snowmelt as it dribbles through the soil. I wonder how long it will take for this cupful to reach a creek and eventually pour out to sea.

I find human objects, too. Loggers’ axes and wedges and chokermen’s cables. Mostly they are things that have broken or been used up and tossed aside. Empty Gatorade bottles and juice boxes. Silvery pouches that once held Hickory Sticks and Planters Peanuts. Gas cans that slowly erode, oxidized and consumed by the outdoors. Paint weathers. Edges dull. Sometimes, when the cut is really old, I can’t tell what an object is without picking it up and holding it to the daylight. Sometimes I find some stray bit of cast-off machinery. The forest eats the chain saw instead of the other way around.

There is a peculiar energy to a cut block in spring—a cold, moist sizzle. Although the trees are gone, a galaxy of buds and seeds and eggs and creatures waits underground for the right day to burst forth. They build, cell upon cell, with unseen industriousness. Their progress is as inevitable as the French curls of ocean currents or cumulus clouds tumbling across the sky. Nature marches ineluctably forward. It’s why blobs of moss grow on cement and mold blackens bathroom caulking. Why we declare war on the dandelions in our lawns. Outside, beyond our fences and sidewalks and window panes, something is always devouring something else. Some ugly, tough-stalked stinker of a flower struggles up out of rubble. It rises, dies off, is eaten or rots down to make room for something else to grow in its place. That’s plant destiny. It’s our fate, too.

If you could liquefy this energy and turn it into something drinkable, like a green fluorescent protein, you could bottle it and make a squillion dollars. Verdant pastures might spring from deserts. Grasslands from toxic-waste dumps. Humans who drank it would never get old and never need to sleep. Nobody would lose their hair. We could charge ourselves up with sunlight. We could jump over buildings and fling ourselves from bridges and never suffer any injury at all.

Some people think planting trees is as boring and crazy making as stuffing envelopes or as climbing a StairMaster. I love my job for exactly the opposite reason, because it is so full of things. There are so many living creatures to touch and smell and look at in the field that it’s often a little intoxicating. A setting so full of all-enveloping sensations that it just sweeps you up and spirits you away, like Vegas does to gamblers or Mount Everest to climbers. It has a way of filling up a life with verbs that push into one another, with no idle space in between. So that you just can’t believe all the things you saw or all the living beings that brushed past your skin.