Darkness is coming. Even through the leaden clouds I can sense the fading of the light. The day is made darker by an unrelenting rain that drips off the hemlocks and down the back of my neck. The trail from Five Ponds has turned to an obstacle course of slippery rocks and troughs of black muck. My companions abandoned their chatter miles ago and now slog along in silence. The only view we’ve gotten today has been framed by the hood of a raincoat. Wet clear through, I shiver. I know we won’t make it out by nightfall. We need to stop. We need to get warm.
We drop our packs under a canopy of spruce, where the dense branches offer some shelter from the rain. But the ground is wet. The tents are wet. Even the sleeping bags are streaked with damp. While the others set up camp I scrounge for firewood in the drizzling dark. Every log and branch is soaked. I sigh and push through dripping branches into a small clearing. Help appears, gleaming among the dark trunks like a candle.
This old yellow birch, its bark in tatters, was probably dead long before this spruce thicket was even born. Before long I have a sheet of its skin tented over the fire circle to keep the rain off my precious pile of twigs. My friends are scoffing at the hopes of a fire, but they don’t know yellow birch. I carefully peel a handful of curls from the bark. They come off in satiny ribbons the color of sand. One by one I tuck them into the center of my pyramid, an altar to fire. One bright match flares against the bark and subsides in a sigh of disappointment. But, after a long second, a roll of dark smoke appears and the bark ignites with a crackle. Despite the dampness, yellow birch burns like fat in the fire. The heat drives the water from the spruce twigs, and they too are alight. I once pulled yellow birch bark from a log fallen into the lake and still it lit with a single match.
In a rising cloud of incense, the scent of safety fills the air. We are transformed from a sodden band with a dinner of wet trail mix to a laughing circle around a bubbling pot of soup. Such is the gift of yellow birch. It has never let me down.
As a hiker, paddler and professor of plant ecology for two decades at the State University of New York College of Environmental Science and Forestry’s Cranberry Lake Biological Station, I’ve spent wonderfully long stretches of time in the field with my students. They come to know all the plants and their scientific names. They call yellow birch Betula alleghaniensis. They learn its habitat requirements, ecological interactions and, perhaps of greatest value, they grow into a relationship with the plants that surround them, and they recognize them as life sustainers.
As I pack for a camping trip, I have often forgotten my toothbrush amidst raincoats, matches and first-aid kit. But I know I could leave each of these things at home thanks to the benevolence of yellow birch. The twigs make a darn good substitute toothbrush; chew the end of one and it separates into a tuft of soft, wintergreen-flavored bristles. The wintergreen oil is both flammable and medicinal. It contains methyl salicin, a pain reliever and anti-inflammatory well known to the native people who share its habitat.
Yellow birch and its cousin paper birch are also rich in betulinic acids. Contemporary pharmacologists have verified the antiviral and antitumor potential of this plant medicine, which has been part of the indigenous pharmacy for generations. The active chemicals are present in very small quantities but become concentrated in a fungus that occurs commonly on birch. Known as chaga (Inonotus obliquus), this black, grainy mass on the bark looks like a blackened wound.
When I camp among birches, I have the feeling of well-being I had visiting my grandmother’s house. She would often have cold root beers waiting for us kids, and old-fashioned root beer was flavored by birch. It’s truly a multipurpose plant: warmth, shelter, fuel, medicine and, in an emergency, clothing. One wet October I was canoeing the Oswegatchie River and the skies opened up. I paddled to shore to put on my rain gear. I found my jacket right away, but as I rummaged through my duffel I realized that I’d left my waterproof pants behind. But no worries—I found a makeshift pair lying right there on the forest floor.
Yellow birch logs have the useful habit of rotting from within. The bark is extremely resistant to rot and may remain intact while fungi and beetles reduce the wood inside to powder. What appears to be a solid downed log is often a shell of birch bark wrapped around the damp dust of decomposition. I plunged my knife into the limb and sectioned off a piece about the length of my thigh. I stood it upright and the fragments of wood slumped out the bottom, leaving a hollow pipe of birch bark. I worked my way down the log from the biggest diameter to the tapered end, slicing off segments and emptying the contents until I had my rain pants. Brushing away stray centipedes I stepped into the tubes and shimmied them over my thighs, then pulled the smaller pieces over my calves like shaggy kneesocks. The smallest tubes I carried with me to the canoe, walking like a tin man. Back in the boat, I slid the bark over my shoes to complete the ensemble. Dressed as a rotten log, I paddled down the river, warm beneath my leggings as the rain poured down.
Though yellow birch usually presents to the world a cool, polished exterior, its heart is soft and yielding, and its wood decays easily. Yellow birch trunks, living or dead, frequently wear the gray conks of Fomes fomentarius, also known as the tinder fungus. Before the days of matches, an ember was a thing of great value, the difference between surviving and not. New fire could be made with bow and drill, but only at the expense of cold, wet hours. Yellow birch and its tinder conks offered an alternative. An ember placed in a hollowed-out conk can smolder for hours. It slowly consumes the dry interior but stays cool enough to be held in the hand. Native people used tinder conks to carry fire from place to place, rekindling the coal each evening with curls of yellow birch.
Even in decline, a birch has a lot to give, and not just to humans. Often dead birches are standing columns of sawdust, held up only by the bark. Still, they are high-rise apartments for insects, diners for woodpeckers and winter quarters for chickadees. When logs fall to the ground, holes get torn in the bark, and through them rise gardens of Canada mayflowers and young birches. Long after the logs have subsided into soil, the bark remains, a crumpled silver skin gleaming among the leaves.
I love to spend the night beneath a birch-bark roof. In the language of the Potawatomi side of my family, a wigwam bears the name of its maker, wigwaas, or birch bark. Waterproof sheets of wigwaas are shingled over a circular frame of maple saplings—no need to take bark from a living tree; the dead ones give it freely. From my bed, the dome above is speckled with skylight peeking through tiny openings in the bark. A sleeper is held in the roundness of the house and surrounded by the scent of the earth; it feels like a nest, a burrow, a womb. I think the design of a wigwam was taught to us by birds. One day I found a vireo nest, blown down from the trees—a perfect little bowl of twigs woven with strips of coppery bark.
Yellow birch is highly prized as a timber species in the Adirondacks, especially for veneers cut to reveal its beautiful grain. But the tree’s generosity extends far beyond what it provides for people. Yellow birch is one of the most abundant trees in the Adirondack forest. Its papery leaves decay into thick black humus. A rotting birch log provides habitat for myriad invertebrates that faithfully render trees back into soil. Fungi of every description, brilliant orange mushrooms and multistriped polypores surge up from the ripening wood. All winter, deer browse on the young twigs. Birch seeds, borne in conelike stalks, are eaten by squirrels and birds, especially in winter, before they are teased away by the wind. A snowshoer may find the surface of the snow flecked with birch seeds skittering over the icy surface as if they were looking for something.
What they seek is a hole in the canopy, where a windthrown tree has pulled up a mass of soil and roots, known as a tip-up mound. By spring the seeds have settled onto the exposed earth and sprouted into a sprinkling of saw-toothed seedlings. Yellow birch is an opportunistic species, taking advantage of bright gaps caused by these disturbances of the forest. Young plants stretch toward the light and put down roots through the piled mound of turned-up soil and rotting wood. Over time the mound erodes, leaving the roots exposed like bare legs. Sometimes you see these birches standing on their roots like stilts, the legacy of beginning life after a treefall in a storm.
Bark is the dry hard face that a tree presents to the world. The outer layer is dead, like the husk of a nut or the shell of a turtle. But like many a tough facade, it’s only a cover for vulnerability. Beneath the surface of yellow birch lies a moist, sweet-smelling layer of living tissue: the cambium, cool and slippery to the touch. This is where cells are born. Every ring of wood, from decades past and decades to come, begins here. Just one cell deep, cambium forms a paper-thin envelope from twig to root. Cambium cells are constantly dividing to yield the girth of a tree. Xylem and phloem, the building blocks of trunks, arise in an ongoing file, a long line of cells stretching from the centuries-old heart of the tree to new wood made yesterday. Yellow birch protects its cambium not with bulk like an oak or a redwood, but by sheer density. Birch bark is built layer by papery layer, like a ream of oil-soaked parchment, packed together in a waterproof barrier. The same oils that so willingly give us fire seal in moisture which nourishes new cells and keeps out insects and microbes. However, barriers always entail a hidden cost; what keeps water in can also keep oxygen out. The labor of birthing new cells demands oxygen. Birch has struck a compromise: the dark horizontal stripes that characterize birch bark are lenticels, slits through which the cambium can breathe.
There’s a point on East Flow, on the edge of Cranberry Lake, that’s practically a pure stand of young yellow birch. Something must have happened there, a log clearing or a fire that bared the ground and let them all start at once. With their slender trunks, glossy bark and masses of golden curls, they remind me of young women. (Poet Samuel Taylor Coleridge called birch “the lady of the woods.”) Radiant in the sunshine, they sway in the wind, and their leaves swish overhead.
As the cambium adds width the old bark gets tight and tears away. The bark beneath is even smoother and more luminous. Consequently, mosses and lichens rarely attach to young birches. It is as if the youthful tree, proud of its burnished skin, prevents anything from obscuring its beauty. Any mosses that do get a foothold might well be cast off when the bark peels away. But the trees live a long time, up to two hundred years. Gradually, they start to gray as they accumulate life and lichens. One yellow birch I know at the foot of Graves Mountain, nearly three feet in diameter, is a mass of silver curls, with roots that stretch out in every direction. It commands its space with a dense canopy, a tree of influence in its community. It launches seeds into the world from high branches.
After a century or so, the faces of these old grandmother trees start to show the tracks of life. As growth slows, the bark does not renew itself so quickly and becomes shaggy. Stories become visible—the woodpecker visit, the branch-breaking ice storm, bear wounds callused over. Old yellow birches are bedecked with mosses and threads of liverworts. Orb weavers take up residence in knotholes, and beetles raise families in tightly coiled curls. The big trees have an air of understanding, growing into their own skins and encouraging the growth of others. I’m learning a lot from wigwaas about growing old.
At home, writing beside a crackling birchwood fire while the rain pours down outside, I throw on another log and watch the curls roar into flame. Such a generous tree. I keep returning to the question of reciprocity: What gift would birches cherish in return for their many gifts? First and foremost they would benefit from our careful safekeeping of their lands and the atmosphere and rains that sustain them. They offer up their comforts with such maternal warmth, perhaps they’d also like what all grandmothers appreciate: respectful behavior, a heartfelt thank-you and a letter signed with love.
Robin Wall Kimmerer’s book Gathering Moss (Oregon State University Press, 2003) was awarded the 2005 John Burroughs Association medal for natural-history writing.