Natural Acts

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Natural Acts Page 10

by David Quammen


  This dramatic lack of vitality proves nothing, of course, about what causal role the smelter wastes and the erosion from denuded hillsides around Anaconda may or may not still be playing. It simply correlates. Consider it, if you wish, purest coincidence. It is not, however, mythical. It is real.

  Later Benowitz and I were careful to shower ourselves down with clean water. “River-snorkeling,” he told me, and he should know, “is not supposed to be a death sport.”

  The Tree People

  SOME HUMANS HAVE A SPECIAL RELATIONSHIP with trees.

  I’m thinking here not of the professional foresters, nor the academic dendrologists, certainly not the barrel-chested and flannel-shirted fallers. No, it’s gentler folk I have in mind. Persons neither scientific nor pragmatic, whose encounters with trees tend to be more intimate, more spontaneous, marked by an altogether different degree of sensitivity and—it might not be going too far to insert the word “mutual” here—appreciation. People who can actually quiet themselves sufficiently to gaze at one individual tree and perceive there a real living creature conducting its own mortal business. This isn’t as easy as it sounds. “The tree which moves some to tears of joy is in the eyes of others only a green thing which stands in the way,” wrote William Blake. These genuine tree people are rare.

  John Muir was one—read his account of riding out the thrills of a mountaintop storm while perched in the upper branches of a hundred-foot spruce. Another was that curious historical figure Jonathan Chapman, dead in 1845, later sentimentalized under the name Johnny Appleseed. Still another is the British novelist John Fowles, who has written an interesting and little-known non-fiction book titled The Tree, in which he avows: “If I cherish trees beyond all personal (and perhaps rather peculiar) need and liking of them, it is because of this, their natural correspondence with the greener, more mysterious processes of mind—and because they also seem to me the best, most revealing messengers to us from all nature, the nearest its heart.” Among this group of tree-loving people, too, is my own father.

  Unlike Muir, he has never rambled solitarily among the California sequoias, my father. Unlike Fowles, he offers no elaborate philosophical theories for his special attachment. Like Chapman, he is simply a planter. Ever since I can remember—let’s say at least thirty years—this man has been planting and tending and doting on trees. He has never sold a board-foot of timber. He has never carried a bushel of fruit to a fair. He barely consents to own a saw. And behind him his life stretches out like a burgeoning, flourishing woodlot.

  For a long time it made no particular sense to me.

  At the beginning there was a half-acre of nearly bare real estate, formerly farmland, at the suburban fringe of a city in the southern Midwest, not far from the Mason-Dixon Line. Upon the half-acre sat a new house and a stately old black walnut tree, not much else; beyond the fence marking the west edge of the property rose a wild stand of high grass and thistle, through which a foot trail led to unspoiled hardwood forest that went on for several miles. Across that fence was a miniature wilderness area for the delectation of young boys. Then, gradually, bits of forest came to the half-acre lot.

  A soft maple was planted up front near the road. A hard maple just out the kitchen window. A sweet gum beside the driveway. A pin oak near the old well. An apple tree off at the northwest corner, keeping company with the compost heap. A little dogwood. A Scotch pine, which often afterward seemed to be struggling against heat prostration. More maples along that west fence. Eventually, getting fancy, a ginkgo. And a magnolia tree, a hapless and delicate magnolia, to the right of the front door. The earliest of these were poached as saplings from the adjacent woods, carefully transported home on the footpath, and replanted as adoptees; later it became necessary to patronize a nursery. From my point of view (roughly waist-high then), the place had become a nursery itself. Finally the man in question bought me a rake, and I was not amused.

  It had become necessary to patronize a nursery because by the time I was old enough to operate that new rake, the wilderness area over the back fence had disappeared. Bulldozers had scraped it away. In its place there was now a tract suburb of medium-sized boxes. Paved driveways and sidewalks. Tulips. Myrtle in neat patches. Precious few trees.

  I sat high in the crow’s nest of that old black walnut tree, years passing, and watched this transformation. A valuable early lesson, with the resonance of a parable. Still grudging my time at the rake, I could see after a while that the man, the planter, my father, was not insane after all. Not even perverse. As the forest was massacred, as the neighborhood turned into concrete and crabgrass, on our small island there was a continual spreading of new branches. Local trees and exotics thrown together in strange juxtapositions, most of them thriving, fighting one another genially for sunlight and water and the attentions of the chief arborist. He was running his own gene bank. I would not want to be so highfalutin as to call this half-acre a symphonic orchestration of trees; but it represented at least a pretty good Dixieland band. The planter enjoyed his son’s approbation for a couple more years, until a midwinter ice storm hit the magnolia, at which point it seemed that things were perhaps being taken too far.

  This would have been about 1963. In that peculiar borderland climate, ice storms were an occasional feature of what passed for winter. Cold sleet would begin falling at night, as the temperature dropped, and by morning the entire city would be glazed with a very beautiful and extremely treacherous eighth-of-an-inch layer of clear ice. Power lines down. Fender smashing against fender. Hips being fractured. I remember vividly how ice fragments and sparks would fly from the overhead wires that fed juice, via long antennas, to the old electric city buses. The ice storm in 1963 was especially bad, and instead of an eighth-inch thickness, there was a quarter inch. Over any large surface area, like the crown of a tree, that amounted to considerable weight. The conifers, adapted to serious snows, could take it. The hardwoods were bare and streamlined. But the magnolia, a southern-bred creature, too naive and injudicious to drop its big trowel-shaped leaves from its brittle limbs after the autumn frosts, was caught in a wretched position.

  Every leaf was lacquered thickly with ice, hundreds of pounds in all, the whole tree about to collapse like so much Steuben glass in a garbage compacter. And so, on that Saturday morning, there was the droll spectacle of a man and his fifteen-year-old son (the latter an unwilling draftee, with places to go and other enormously pressing things, now forgotten, to do) taking turns on a stepladder to break the ice—gingerly, one leaf at a time, with raw cold hands—off that desperate magnolia.

  I remembered the magnolia’s trauma, and its rescue, just yesterday while reading some scientific papers on an extraordinary species of tree called the bristlecone pine. The bristlecone was originally to be the main subject of this essay—now largely preempted, but never mind. The bristlecone will get its full starring role some other time. It can wait. It knows how. It is a tree accustomed to taking the long view. Unrecognized by biologists until about thirty years ago, bristlecone pines in the mountains of the American Southwest are today known to be among the oldest living creatures on Earth.

  We’re not talking about the age of a species, understand, but about venerable individuals. One noble specimen of bristlecone, found alive in 1964 on the shoulder of a high peak in eastern Nevada, was calculated to be 4,900 years old. That single tree sprouted from its seed and began putting out needles, in other words, around the same time the Egyptians established their first kingdom. No pyramids yet. The book of Genesis was still in galleys. This was a very old tree.

  A number of curious facts emerged from those journal papers on the bristlecone, most of which have no pertinence here, no bearing upon the subject of the man, the ice storm, and the magnolia. But two of them do.

  First: Dendrologists have discovered that longevity among individuals of this most long-lived of earthly creatures is inversely related to the hospitableness of its living conditions. The tree thrives, over great lengths of ti
me, on adversity. The more harsh and ungiving its particular locale, the longer a bristlecone tends to live. At lower elevations within the mountains of its native range, places where soil is decent, wind and erosion are not extreme, water is available in good supply, the bristlecone grows large and robust, but does not seem to survive much beyond 1,500 years. These ages can be gauged rather precisely, from a core sample or a full cross-section, by counting the annual rings laid down through the trunk. At higher elevations, right up at the edge of the timberline, on steep south-facing slopes of stony soil that is poor in organic material and chemical nutrients, where little water is available, winds are relentless, growing conditions are generally lousy—here the bristlecone lives as a gnarled dwarf. But long. Often enough in this harshest environment a bristlecone survives its four thousandth birthday. Obvious moral: When the growing is tough, the tough keep growing.

  The second odd fact is corollary to that one. Certain dendrologists who count bristlecone tree rings have taken to writing of two separate characters of tree within the species. These are the “sensitive” bristlecones and the “complacent” bristlecones. The sensitive bristlecones are those that respond to climatic fluctuations, such as a year of exceptional drought, by laying down a drastically narrower growth ring that year, or possibly no ring at all. A complacent tree records no such response. Maybe it shouldn’t be surprising that the complacent trees (as reported in Science, 1968) tend to be those that are younger and more comfortable. Meanwhile the ancient trees, struggling through four thousand years of thirst and starvation, solitary on exposed ridges, grotesquely shaped, hunkered down, clinging to life with only two or three green branches—these are the ones that leave a record of sensitivity.

  Now it seems to me that this discernment of “sensitivity” and “complacency” among various individual pine trees, silently living to millennial ages on their high mountain slopes, must constitute some sort of breakthrough percipience for the botanical sciences. And it compels me to wonder about that beleaguered magnolia on the half-acre woodlot at the edge of the midwestern city.

  Was the magnolia by disposition a complacent creature? Or was it, as I hope, sensitive? Did it appreciate, in some sense, during the year of growth following that 1963 ice storm, what the man with the stepladder and the raw hands had done for it?

  The house and the half-acre have long since been sold to strangers. The magnolia, last time I was in the city and drove past, looked neglected: a broken crown, whole branches on which the leaves were a sickly brown. Too bad. It may not survive another big ice storm. Certainly it won’t live to see four thousand.

  But might there remain, perhaps, in its heartwood, some record of response—just a slight thickening to one annual ring, like a grateful sigh—to that mildly eccentric act of love? Can a magnolia remember a man?

  ELOQUENT PRACTICES, NATURAL ACTS

  Love’s Martyrs

  LIKE WOODY ALLEN, the English poet John Donne was obsessed in his younger days by love and death. Throughout Donne’s early work those two motifs recur again and again, linked so closely together that they come to seem almost logically inseparable, two sides of a macabre equation, evoking each other almost interchangeably. Love is a manner of dying, Donne suggests; and vice versa. For instance: “I cannot say I lov’d, for who can say / Hee was kill’d yesterday?” Another poem contains the tender sentiment “Since thou and I sigh one another’s breath, / Who e’r sighes most, is cruelest, and hastes the other’s death.” In still another, a man speaking from his own grave declares himself “love’s martyr,” dead of an excess of passion. During the sixteenth century in England, this oxymoronic linkage of the two concepts, love and death, was enough to get an ardent young man eventually categorized as one of the “metaphysical” poets. Nowadays it would make him a theoretical population ecologist.

  The notion with which John Donne was flirting, in all that love-and-death poetry, is studied today as a curious phenomenon of evolutionary ecology and denoted by the label semelparity. That fancy word is, of course, just another bit of the formal jargon that scientists take cruel joy in inventing. The same thing is more casually known, with a lewd nod from one science to another, as Big Bang reproduction.

  Semelparity: An animal or a plant waits a very long time to procreate only once, does so with suicidal strenuousness, and then promptly dies. The act of sexual reproduction proves to be ecstatically fatal, fatally ecstatic. And the rest of us are left merely to say, Wow.

  As a strategy for perpetuation of a species, semelparity is not well understood. But the list of known semelparous creatures is intriguingly diverse. Bamboos do it. A group of hardy desert plants called the agaves do it. Pacific salmon do it. The question is why. What can these three kinds of organisms, apparently so dissimilar, have in common? Why should all three, living in drastically different environments with drastically different life histories, be similarly committed to dying for one taste of love?

  The answer, according to cautious speculation by some ecologists, may be as simple as a few symbols. Natural selection, these researchers say, tends to maximize, for each age I, the sum Bi + pi (vi+1/v0). They may be right, but if you’re like me, any such clot of algebraic erudition immediately causes alarm bells to ring in your head, sprinkler systems to begin dousing your overheated brain, and your eyes to slide straight off the page like a cheap ballpoint skidding across oilpaper. But wait. The idea wrapped in that ugly cryptogram happens to be rather interesting, and just possibly it can also be said in English.

  First, a few concrete facts. Five different species of salmon migrate regularly from the Pacific Ocean into the rivers of western North America. They are headed upstream to spawn, and for each individual fish the journey is a return trip back to that same freshwater tributary where it began its life. Some of these salmon (the Chinook of the Yukon River, for instance) will travel as much as 2,000 miles, climbing through rapids, making ten-foot leaps to clear the cascades, dodging predators, fighting constantly upriver at an unflagging pace of perhaps 50 miles per day. The effort and determination involved are prodigious, but it is a one-way trip. Soon after having spawned, every male and every female of these five species is dead. Decomposing corpses pile up in the eddies, turning clear mountain water funky with rotting flesh. Among those lucky fish that have completed the trip, won a mate, found genetic fulfillment in the gentle current above a gravel spawning nest, there are no survivors.

  Certain types of bamboo make a long journey to breed also, but the distance they cover is measured in time. The common Chinese species Phyllostachys bambusoides, for instance, has a regular life cycle of 120 years. Historical sources back into the tenth century record its episodes of massive synchronous flowering. Each time around, a vast number of P. bambusoides individuals begin life together as new sprouts; for 120 years they grow taller and sturdier, putting out leaves and branches, storing away energy, adding clones of themselves to the population by a nonsexual budding process, maturing together into a dense grove; then, after the appointed twelve decades, they suddenly and simultaneously produce an awesome profusion of flowers. The blossoms fertilize one another by wind. Seeds fall like heavy hail, coating the ground, ankle-deep to a man. And the 120-year-old progenitors all immediately die.

  Members of the plant genus Agave, meanwhile, are content through long years of growth and celibacy to resemble giant artichokes peeking out between desert rocks. They are succulents, related to lilies but preferring a hard life on dry hillsides, such as those of the Sonoran Desert. They unfold their leaves in a spiral rosette, each leaf tipped with a sharp spine for protection against browsers, and they range by species from the size of a small porcupine to the size of a 300-pound octopus. Like the bamboo, they can set clones of themselves by budding, but their primary mode of reproduction is sexual. Years go by uneventfully, an agave grows large and vigorous until, with startling abandon, one season it produces a towering flower stalk. This great inflorescence will be notable not for the beauty or fragrance of its
blossoms but for its sheer height. From a big agave, in just three or four months the stalk might shoot up thirty feet, sturdy and straight as a young lodgepole pine. It’s a flower that you’d cut with a chainsaw. Pollination is done by insects and bats; seeds ripen and drop. And down below, shriveled and brown, the agave dies away, as though speared through the heart by its own flowery stalk.

  This is semelparity, at work in the moist tropics of Asia, on the sere slopes of southern Arizona, at the headwaters of the Yukon River. A curious person naturally wants to know why, in each case, a single act of sex should prove deadly. But even more interesting, it seems to me, is the first derivative of that question: Is there any one answer that can explain why sex is terminal in three such disparate cases?

  A man named William M. Schaffer says yes, and offers this:

  Hold the sprinklers, hold the alarm. What he is talking about is simply a delicate balance between love and death.

  Dr. Schaffer is a respected theoretical ecologist at the University of Arizona. In a half-dozen papers published over the past decade, alone and with various coauthors, he has proposed a theory of how evolution tends to produce optimal life-history strategies for different animals and plants. This theory entails enough mathematical bebop to make the average human swoon. Descriptive numbers for a particular species can be inserted into Schaffer’s equations, a lever is then pulled, a crank is turned, and the theory will posit how the creature should act if it wants to survive the long-term Darwinian struggle. That’s the kind of thing theoretical ecologists do. Semelparity is quite useful in such theorizing, because it involves the love-and-death balance taken to one logical extreme.

 

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