Of rising sap -- and temperatures -- in the Wisconsin woods
A sharp bit cuts a clean hole. Each year as winter slides toward spring, I head into my family's woods in northern Wisconsin with the best drill bits I can find. I am the fourth generation of my father's family to tap our sugar bush, a hillside grove of 200 sugar maples whose warped limbs interlace high above the forest floor. Together with a few soaring pines, these maples form an enclave partially spared by the loggers who began clearing this area late in the 19th century. Sugar maples grow throughout our woods, but only in the sugar bush are there old, shaggy-barked trees -- trees that might already have been growing here in 1837 when the Ojibwe, who call sugar maple "the man tree," ceded this land to the United States government.
Tapping maples is, in principle, fairly simple: Drill a small hole an inch and a half into the trunk of each tree, insert a spile, and place a container beneath it to catch the drips. On days when the maples are plashy, a good one runs over a gallon of sap, which must be gathered and boiled down to the brink of sugar saturation. Hitting the perfect density is the trickiest part of the process. Stop too soon and the syrup will spoil easily; boil too long and some of the sugar will form rock candy.
Folk methods for telling when syrup is done abound. Some old-timers watch the size of the bubbles rising in the boiling syrup. Others wait for the syrup to "sheet" from a spoon. Most novices track the syrup's boiling point with a candy thermometer and stop cooking when it hits seven degrees above the boiling point of water at their current elevation and barometric pressure. The commercial standard is to measure the syrup's specific gravity with a hydrometer, a glass bulb with a graduated stem that floats in the syrup like a fisherman's pencil bobber. Once the syrup has reached its proper density, all one has to do is filter out the solids that precipitate during the boiling process -- a gritty but innocuous mixture of calcium and magnesium salts referred to as "sugar sand" -- and bottle the finished syrup for storage. Nothing is added; the trees supply all ingredients.
For drilling tapholes, I use a carpenter's brace, a device now most often found in the boxes of old tools at estate sales where, in my part of the country, the objects that gathered around a human life rest together on hay wagons for a few final, obituary hours before being dispersed. A brace is little more than a steel shaft with a rectangular bow in the middle. At one end, jaws and a chuck adjust to receive a drill bit; at the other, a free-spinning mushroom-shaped head transfers pressure from one's hand through the shaft to the bit.
I still have the first I ever used, one passed on to me by my maternal grandfather, with whom I often sugared when I was a boy. Its darkly oiled wooden handles still bear the highlights burnished onto them by his hands. I like the rhythm I fall into when I use it, the familiar way it squeaks with each revolution, the way a blond ribbon of sapwood twines down the shaft of its auger as the cutter loops patiently through a tree's annual rings.
My grandfather had me pay attention to this wood. During one of my first faltering attempts at tapping, he gestured toward the curls dribbling from the hole. "Watch the shavings," he said, his voice ragged with age, like the woolen shirts he wore. "Make sure you're not drilling into rot." Stained, crumbly shavings indicated decay inside the tree, and when we saw them, we abandoned the hole for fear the syrup might be tainted. Only when the turnings maintained the pale hue of cornstalks bleached in the sun -- the color of healthy, living sapwood -- would we tap one of his cast-iron spiles into the hole and hang an ice-cream bucket from it. I often lingered then, so that I could watch the first limpid drop ride down the channel of the spile and gather before plunking into the pail. When the trees were running well, the woods were staccato in our wake, the best trees ticking 60 drops a minute.
The trees do not always run this well. Variables like frost depth and soil moisture make sap flow unpredictable, even though the immediate weather conditions that favor good runs are well known: calm, sunny days when the temperature climbs into the mid-40s after overnight lows in the teens or 20s. The run is driven by repeated freezing and thawing, what the naturalist John Burroughs called a "certain equipoise of the season." An enthusiastic syrup maker himself, Burroughs wrote that in "New York and New England, the time of the sap hovers around the vernal equinox. . . . As the days and nights get equal, the heat and cold get equal, and the sap mounts." This timing is also fairly accurate for my family's sugar bush, which, in keeping with the theme of equipoise, sits only 40-odd miles north of the 45th parallel. Here at the midway point of the hemisphere, winter and spring balance nicely on the knife edge of the equinox, the blade that in so many of the world's calendars has sliced the seamless fabric of the seasons into old year and new, beginning and end. There is found poetry on a planetary scale in the fact that halfway between Earth's equator and north pole, on the day when sunlight matches darkness, water can both freeze and thaw. Such is the rare fruit of chaos on which life depends and religions feed.
For the maples, as for us, there is something bodily familiar in the way our planet rocks its poles back and forth between the torrential light of the sun and the frost-crystal glinting of distant stars. Cut a maple so that its stump can be studied like the face of a clock: Its rings record the pendulum's swing, each annulus, like the year itself, both dark and light. The light portion of an annual ring is the rapid growth of spring and tends to be wider than the dark, which is added as summer progresses, growth slows, and cell structure changes. Winter halts growth completely until spring triggers another burst, adding a new tally mark to the reckoning.
In four generations, no one in my family, so far as I know, has ever cut one of our large maples so that its rings could be counted. Clearly, however, the trees are old. Sugar maples grow slowly and can live more than 400 years. A "wild-grown" tree, one not managed to receive optimal light and nutrients, often takes more than 50 years to reach the 10-inch diameter considered minimum for tapping. Our sugar bush, more wild than not, has trees nearing 30 inches in diameter. That my family never cut these trees is remarkable. Sugar maple vies with red oak in our region for top lumber prices, and my great-grandfather, grandfather, and uncle all logged and operated sawmills on the farm. They also cleared land to make fields. What saved our maples I'm not sure; most likely it was some combination of the sweetness of the trees' sap and the rockiness of the soil beneath them.
My father and I did recently cut a smaller maple in the sugar bush, one about nine inches in diameter that was damaged when we felled a large, sickly pine. The maple's oval stump, like a finely banded agate, had 98 annual rings, the tree in some years having added no more to itself than the thickness of a heavy coat of paint. What this means -- part of what it means, at least -- is that when I bore an inch and a half into one of these maples to tap it, I may well be drilling back in dendro-chronology roughly to my own birth, the fragile helix of shaved wood falling to the snow at my feet a transect of my own life.
Sugar maples are also called hard maples or rock maples; their wood is used for bowling pins, and the trees themselves seem similarly resilient. In Wisconsin, where they thrive, the highest recorded temperature is 114°F and the lowest, recorded one county east of our sugar bush, is -55°F: a span of 169 degrees. A bicentenarian tree hulking patiently through such extremes on a buttressing flare of roots can seem beyond human concern. My great-grandfather and grandfather both, I'm sure, trod beneath the boughs of our maples confident and content that the trees would outlive them. Neither man died young, but both were right.
This may seem an odd thing to envy in their lives, I suppose, but increasingly I do. I worry about threats to the trees, most of them human in origin yet beyond my control: insects like pear thrips, gypsy moths, and Asian longhorned beetles introduced from other parts of the world via global networks of commerce; acid rain; increased solar radiation resulting from ozone depletion; and global climate change. The last is particularly troubling. Computer models developed by scientists from the USDA Forest Service predict that virtually all of the contiguous United States, including Wisconsin, will be unsuitable for sugar maples once atmospheric carbon dioxide reaches double its preindustrial levels, something the Intergovernmental Panel on Climate Change estimates will happen within 100 years.
The average time of the sap run has, in fact, already changed. When John Burroughs was sugaring in his part of New York, the climate was noticeably cooler than it is now. Born in 1837 just four months before the Ojibwe formally lost what became my family's farm, Burroughs learned to expect that in the Catskills the sap would run near the vernal equinox, as it does now in northern Wisconsin. Our sugar bush is 200 miles farther north than the Catskills, however, and the sap run here would likely have fallen after the equinox in Burroughs' day. Not many Euro-Americans were in northern Wisconsin then to note it, but the Ojibwe were. Brethren of the Algonquin tribes who are believed to have first taught colonists from France and England to tap maples, the Ojibwe have visited seasonal sugaring camps for centuries. Tellingly, the early Ojibwe lexicons from what is now Wisconsin and Minnesota translate Iskigamizigegiizis, or Maple-Sap-Boiling Moon, not as March but as April.
The problem for maples in global warming, of course, is that the climate will deviate relatively quickly from precedents in the trees' genetic memories. Sugar maples can cope with the temperature extremes in the interior of our continent because the climate, although dramatic in its swings, is rhythmically variable at the scale of the seasons. The local, periodic fluctuations of light and temperature and precipitation caused by Earth's wobbling orbit are the obstacles -- and opportunities -- through which the tendrils of the trees' DNA have wended from one generation to the next, and the trees' DNA reflects this in both its sequencing of base pairs and, more figuratively, its helical form.
One early cliché of Western anthropology was that moderns consider time an arrow, whereas primitives consider it a circle. More apt than either as a concept for life's earthbound experience of time is the helix. In the geometry of relativity, an orbiting planet mapped in space and time cuts just such a figure, the planet corkscrewing through space-time as each revolution brings it to a position analogous, but not identical, to the one it held the year before; the well of gravity around the sun loops time back toward itself, but time's momentum keeps the circle from closing. Thus, when the winged seeds of the maple -- called "keys" or "samaras" by botanists and "helicopters" by children -- spiral down freighted with the next generation of trees, they mime the deep structure of both the hidden life they bear and the long history that shaped them. That the silhouette of a DNA molecule is a microcosm of Earth's movement through space and time is another masterpiece of chance. In an odd twist on Genesis, space-time has created life in its own image.
Maple sugar is one of the particular blessings of space-time, its sweetness a distillation of life's relationship with a place and its past. Each summer, maples transform solar energy into glucose and then, following the wisdom of genetic record, drop their leaves and wrap some of that energy inside themselves in coils of starch. During winter, the trees convert starch to sucrose, which is highly water soluble and functions as antifreeze. Later, this sucrose fuels spring growth. Maples remind us that the various arrangements of carbon, hydrogen, and oxygen that we call sugars are the basis of life. Photosynthesized glucose ignites most of the biosphere. All animal cravings for sweetness -- everything from a bee's attraction to the sucrose in nectar to a child's yearning for the lactose in her mother's milk -- come back in some way to the fundamental dependence of life on energy first trapped in sugar. It is the most ancient hunger, and maples answer it in a most satisfying way. As anyone who has carried a gathering pail from tree to tree, season after season, knows, this is no simple pleasure, no small thing to contemplate losing within the span of a human life.
I don't have any children of my own. It's a choice I've made, one I suspect my father resents. I understand if he does; I'm an only child, his only chance at a grandchild and a fifth generation for the land. Often, when I'm working by his side in our woods, I feel my own regret. But then I consider the lakes I grew up fishing that are now ringed with houses and signs warning against eating the fish, the stars low along the horizon toward town that have been washed from the sky by the rising electric glare, and the specter of our species having so altered the atmosphere that any child of mine could see our maples die, never to be replaced. Many, I know, would say this is crazy, that things are not so dire. I hope they are right. I do not trust their optimism enough, though, to bring a child into the world on its merit. If they are wrong, there will be too little left of me to be a father.
My father and I seem destined, therefore, to lose the farm and its sugar bush someday into another family's hands, a loss no more painful -- and certainly more just -- than those further back in the land's history. We will, if all goes well, leave these new owners some fine trees growing in rocky ground and perhaps some outdated hand tools placed carefully in a box. If all goes poorly, there may be only a story, one by then of little use, of a family who, through its own dumb luck and others' misfortune, settled on a piece of ground where trees of the most amazing sort grew. The trees' boughs reached toward the sky with all the yearning of prayer and shed seeds that whirled to the ground on damselfly wings. In autumn, their leaves flamed like the setting sun and then fell, leaving the trees looking dead and forlorn through winters that made ice boom and crack on nearby lakes. Yet each spring, the trees came back to life and ran sap that was sweet and clear, sap that could be turned through the alchemy of ice and fire into honey. Each spring for generations, the family took some of this and savored it, until finally the winters turned warm and the sap stopped flowing and the family, like the trees, disappeared.
Devin Corbin is a doctoral candidate in English at the University of Minnesota. His essays and translations have appeared in The North American Review, Literary Magazine Review, and Exchanges. This essay is adapted from a longer version that first appeared in The American Scholar (Spring 2004). Subscriptions: $25/yr. (4 issues) from Box 354, Mount Morris, IL 61054.