|
Reluctant Provider
Why bamboo waits so long between incarnations
By David Quammen
The novelist Louise Erdrich recently published a lapidary one-paragraph essay, excerpted from something longer, that begins, “I would be converted to a religion of grass.”
The tenets of that religion, as she imagines it, would prescribe such grassy behavior as sinking deep roots, conserving water, competing against the overweening intrusiveness of taller and less supple beings (namely trees), sleeping the winter away, rising afresh in spring. The practices of piety would include growing lush in order to be devoured, attaining a certain elegant
but moderate stiffness, and succumbing intermittently to fire. Besides those, she suggests a few other ways a grass should comport itself. “Connect underground. Provide. Provide. Be lovely and do no harm.” Erdrich is alluding particularly to America’s northern tallgrass prairie, but as she certainly knows, the grasses are a diverse group, found worldwide in many variant forms. If
there were such a religion, for instance, the cathedrals undoubtedly would be built of bamboo.
In a sense they already have been. Go ashore from the Sepik River, in the grassy lowlands of northern New Guinea, to gaze at a haus tambaran–one of those majestic ceremonial longhouses, with its soaring roof line that culminates in a high eave–and you’ll see bamboo architecture raised to an apex of reverential grace. This is the sort of building
in which Erdrich’s religion of grass would properly hold its worship.
In her talk about providing, providing, I hear an echo of Robert Frost, and if Erdrich didn’t intend it, the coincidence is large. One of Frost’s more acerbic poems, on the subject of fleeting glory and how to cope with its loss, ends with these lines: “No memory of having starred / Atones for later disregard / Or keeps the end from being hard. / Better to go down dignified /
With boughten friendship at your side / Than none at all. Provide, provide!” The last two words are also the poem’s title, which is what makes them seem so familiar as echoed, oddly, in Louise Erdrich’s nonacerbic voice. I can’t help but wonder whether this was her way of inserting a weedy, ironic subtext into the earnest green turf of her statement. Maybe, at the back of her
mind, Erdrich was recalling that no season of sublimity will keep the end from being hard–not for a person, and not for a wild prairie destroyed by the sodbuster’s plow.
Or maybe her brain, enticed by a scrap of remembered poetry, had strayed farther. Maybe she was thinking that religious veneration itself can be a form of fleeting glory for the venerated. Maybe she was suggesting that even (especially?) gods have their crosses to bear, and that a religion of grass just might not be the sweetest thing that could happen to grass.
My mention of bamboo among the grasses is an act of taxonomic literalism, not poetic license. There are roughly a thousand species of bamboo, and botanists have commonly assigned them to the family Gramineae, along with such other long-stemmed plants as wheat, rice, barley, oats, maize, fescue, timothy, and crabgrass. Among this group the bamboos are peculiar: bigger and
woodier than other grass species, and inclined toward an extraordinary reproductive strategy, delayed gregarious flowering, that I’ll describe in a moment. Delayed gregarious flowering is what gives them an aura of measured but heroic abandon that no other grasses can match. Byron and Shelley, not to mention Frost, would have appreciated it.
The bamboos have been called “primitive” grasses, but their primitiveness has not prevented them from achieving broad distribution, great species diversity within certain regions, and a long history of ecological success. They’ve been around for maybe 200 million years. They’re native to every continent except Europe and Antarctica. An American from the chilly latitudes might
assume them to be tropical, but in fact their primordial range, before humans began transporting them here and there, stretched from southern Chile up into Virginia and from sea level to above 9,000 feet in certain snowy Chinese mountains. The entire southeastern United States was once spackled with the bamboos Arundinaria gigantea and Arundinaria tecta in thick stands casually known as canebrakes. Southeastern Asia, from India through China, is especially rich in bamboo, and tropical America is too. Japan alone supports 662 different bamboos, and the island of Madagascar, isolated but hospitable, contains 30 species, more bamboo diversity than in all of Africa. Madagascar even harbors three
species of lemur that, like the giant panda in China, have become specialized on a diet of bamboo.
At least one of the lemur-eaten Madagascan bamboos contains high concentrations of cyanide, possibly as a defense against browsing by lemurs, and one of the lemur species, Hapalemur aureus, has in turn developed a remarkable immunity to cyanide. Fortunately for the bamboo, but not so fortunately for lovers of lemurs, Hapalemur aureus is one of the world’s rarest primates, and it doesn’t take a very heavy toll. It’s a shy creature, roughly the size of a cat, that lives in a small zone of Madagascar’s southeastern rainforest. I once invested three weeks of waiting in exchange for several brief glimpses of H. aureus, during one of which I got to
watch it blithely munching a stem of that cyanide-rich bamboo.
Beyond the ecological and evolutionary measures of success, bamboo enjoys unparalleled status within human cultures. According to some authorities, it’s the most variously useful kind of organism that mankind has ever encountered–more useful than buffalo or horses, more useful than cows or chickens, more useful even than wheat or rice or coconut palms. One such authority was
Willard M. Porterfield, a professor of biology at a university in Shanghai, who labeled bamboo “the universal provider.” Another was David Fairchild, who after traveling across Asia in the 1920s wrote an admiring chapter, in his botanical memoirs, on “The Bamboo Civilization of Java.” Take away bamboo from the Javanese culture, as Fairchild saw it, and there would have been
scarcely a house left standing, not many bridges, nothing to sit on, nothing to carry water in, no hats, no fences, no erosion control, no birdcages, no scarecrows, no beds. On the other hand, he added with a nuance of regret, “Take away the bamboo from our civilization and we would simply have to go fishing with some other kind of a rod.” Lucky for Fairchild that he didn’t live
to see graphite. Still another and more recent authority is David Farrelly, compiler of a sort of Whole Earth Catalog of bamboosiana. His volume, full of intriguing facts and woozy writing, is straightforwardly titled The Book of Bamboo.
Farrelly is bullish on bamboo. From him you can learn, alphabetically, that bamboo has been made into arrows, awnings, airplane wings, alcohol, boats, bilge pumps, blowguns, beer, cables, cradles, cooking vessels, castanets, dams, diesel fuel, dirigibles, deodorizers…and so on, right down to trestles, umbrellas, violins, waterwheels, xylophones, yurts, and zithers. Farrelly
will inform you that the I Ching, the ancient Chinese book of mystical wisdom, cites bamboo as a symbol of towering vitality tempered by a sense of restraint, based on the plant’s vertical shafts strengthened by horizontal nodes. This represents a genuine insight about bamboo: Anatomically (and otherwise, as we’ll see) it expresses itself in segments
of smooth extension punctuated by abrupt stops. From Farrelly’s book you can discover that bamboo grows more rapidly than any other plant, with some shoots surging upward as much as four feet within 24 hours; that bamboo has been used as a substitute for rebar in reinforced concrete; that hungry Taiwanese consumers eat 22 tons of bamboo shoots daily; that Edison’s first
factory-produced light bulbs were lit with filaments of bamboo; and that, in Hong Kong, skilled workers called Bamboo Men lash 20-story bamboo scaffolds to the faces of skyscrapers under construction. Farrelly also reports that bamboo is known as “the wood of the poor” in India, as “the friend of the people” in China, as “the brother” in Vietnam. And furthermore: “The importance
of bamboo at the earliest, most formative periods of human culture is suggested by the fact that it was deified in some primitive tribes, such as the Piyoma of Formosa.” As Farrelly tells it, the Piyoma of Formosa seem to have been practicing Erdrich’s religion of grass.
In addition to his lists, his facts, and his underpinning argument that bamboo is “a plant of ancient and increasing importance for humanity,” David Farrelly offers a montage of poetry excerpts, political commentary, descriptions of species, do-it-yourself projects, technical and artistic drawings, footnotes, epigrams, a glossary, a discography (bamboo-instrument music from
around the world), and a bibliography that runs to more than 400 items, including titles by Buckminster Fuller, Marshall McLuhan, Maria Montessori, Ivan Illich, Sir James Frazer, Montaigne, Ezra Pound, Stewart Brand, and Frank Lloyd Wright. As this list suggests, Farrelly has chosen to place bamboo in a broad cultural context as well as an agronomic one, and that’s fine. What
puzzles me about his inclusiveness is that it doesn’t extend to the single most interesting work on bamboos that I’ve ever read. There’s no citation of the ecologist Daniel Janzen.
This brings us back to the subject of delayed gregarious flowering. Two decades ago, Janzen discussed it in a journal paper titled “Why Bamboos Wait So Long to Flower.”
The background to the question that Janzen posed was a series of historical observations spread broadly over time. One set involved the bamboo Chusquea abietifolia, a viny species native to the mountains of Jamaica.
In the early 1880s, a few living specimens of Chusquea abietifolia were shipped from Jamaica to the Royal Botanical Gardens at Kew, near the outskirts of London, where they came to the notice of Sir Joseph Hooker, England’s most eminent botanist. Hooker, an old pal of Charles Darwin, had something of Darwin’s aptitude for combining keen observation
with profound inference. Later he wrote of his hothouse bamboos, “In December last (1884) they suddenly burst into flower causing me to fear that, after the manner of so many species of this most remarkable tribe of grasses to which they belong, they may not survive the flowering period.” Bamboos were well known for the trait, among some species but not all, of waiting many years
to flower. After a long period of delay without any noticeable blooming, a population would all bloom simultaneously, set seed, and then–as though fatally overtaxed by their great blast of reproductive effort–promptly die. The same sort of strategy occurs also in Pacific salmon and agave plants. Ecologists nowadays call that strategy semelparity or,
more jocosely, big-bang reproduction.
In addition to the basic breed-once-and-die phenomenon of semelparity, among the bamboos there is something more. Hooker evidently suspected this when his C. abietifolia plants began dying. The long-cycle bamboos had shown a remarkable capability to measure their reproductive delays by some internal mechanism, independent of external signals such
as seasons or drought. They achieved their synchrony without any immediate environmental trigger–like a deaf percussionist in a symphony, counting time to the moment of his great cymbal clash without benefit of hearing the string section approaching crescendo. Whatever had caused Hooker’s bamboos suddenly to flower and expire, it probably bore little relation to their
circumstances at Kew. Contacting someone in the West Indies, Hooker found his suspicion confirmed. In the mountains of Jamaica, simultaneously with his plants in England, whole stands of C. abietifolia had been flowering. They continued flowering throughout 1885.
The old plants dropped their seeds and died. The new generation grew quickly to what looked like adulthood. They thickened their stands by way of vegetative (nonsexual) reproduction, each plant extending its root system and sending up more shoots. But from sexual reproduction they abstained. They were waiting. Then in 1918 came another mass flowering. And in 1949, another.
The delay period of C. abietifolia is now placed at 32 years, give or take a year or two. Each plant seems to count off the years on some internal biochemical timepiece, so that even a few lonely exiles confined to an English greenhouse can deliver their efforts on cue. Dan Janzen, in his bamboo paper, which was published in 1976, mentioned
C. abietifolia among a sizable list of long-cycle bamboos. By his reading of historical and botanical sources, Bambusa arundinacea in India had shown the same 32-year delay period as C. abietifolia. So had Guadua trinii in Brazil. In Pakistan, Melocanna bambusoides was somewhat more patient, with a period of about 48 years. And a Chinese species called Phyllostachys bambusoides, about which there are scattered reports dating back to the year 919, continues flowering on a 120-year cycle, even among populations transplanted to Japan and the United States. “The timing of
seeding in these semelparous species is set by an internal physiological calendar rather than an external weather cue,” Janzen wrote. Natural selection had built that calendar–as well as the habit of using it to coordinate long-term reproductive delays–into the bamboo genes. The question that interested Janzen was why.
The answer, he hypothesized, is predator satiation. Bamboos are driven to such extremes of self-restraint and excess by the enemies that love them too well.
“Who eats bamboo seed? Everybody does,” Janzen wrote, and he offered some good reasons. Bamboo seeds are more nutritious than wheat or rice. There’s no evidence that, like the seeds of many other tropical trees, they contain defensive toxins to discourage predation. (So he said then, anyway, though research on that cyanide-laced Madagascan species might eventually contradict
him.) The fallen seeds are easy to find, since a dense stand of bamboo is generally bare of underbrush. And, best of all, when a population of bamboo cuts loose reproductively after decades of abstinence, the seeds pile up like a blizzard of manna. Janzen cited one report of a five-inch-deep layer of seeds beneath recently flowered bamboo, and mentioned another case (again from
Madagascar, cradle of noteworthy bamboos) of a flowering event that laid down 45 pounds of seeds per acre over an area of a quarter-million acres. Concentrations on that scale represent an irresistible windfall of food.
Just which seed-eating creatures might be attracted to such a banquet? That would obviously depend on which species were native to the region. But the roster of granivorous candidates includes rodents, birds, pigs, elephants, rhinos, deer, and humans. “Rats are so fond of bamboo seeds that the widespread seeding of bamboos may induce a regular plague of them in the
neighborhood,” according to a 1927 report on forest protection in Burma, quoted by Janzen. Another source describes a bamboo-flowering event in Madagascar that added 50 million rats to a nearby area of crops. Asian jungle fowl, wild relatives of chickens, also constitute a formidable group of seed predators. They will eat virtually anything digestible, from insects to roots, but
they seem to prefer seeds, and bamboo seeds in particular. Another Burmese source complained that one species of jungle fowl would “collect in almost incredible numbers into a very small area” when the bamboo went to seed. As for capacity, a single representative jungle fowl was found to have 519 bamboo seeds in its crop.
Then again, humans can converge on a bamboo event in plaguelike numbers, too. Reports from both Chile and Japan mention local people harvesting bamboo seeds as food, especially in lean times. During a turn-of-the-century drought in India, the seeds dropped by mass-flowering bamboo reportedly saved thousands of people from starvation. Janzen also quoted an earlier Indian
account, from 1868, of a flowering that brought 50,000 people out to collect seeds. One adult would gather about five pounds in a day. We can guess that a single rat would take less than that; a pig, more. But human techniques for gathering seed have no doubt improved some since 1868, whereas rats and pigs have presumably stuck with their old reliable methods.
From the bamboo’s perspective, the crucial issue isn’t which predators come, but how many. If the assembled multitudes are capable of eating every seed, then the bamboos have wasted their effort. Reproduction will be thwarted, and that bamboo population will wither toward extinction. But if the species has evolved a
strategy of predator satiation, as Janzen posits, then the total output of seeds will be so vast that even a plague of rats and elephants and jungle fowl can’t eat it all. With the predators satiated, some seeds will be left to germinate.
How does a species of bamboo manage to satiate the predators of its seeds? There are two components to the process, as Janzen proposed it. First, the bamboo makes whatever sacrifices are necessary, whenever it does flower, to produce an extraordinary abundance of seeds. The logical extreme of this component is semelparity: Each reproductive effort is so energetic, so
unstinting, so costly, that the parental plants die of exhaustion.
But an increase in the magnitude of such onetime reproductive outputs would still leave the bamboo vulnerable to a responsive increase in the local numbers of predators. Feeding greedily, breeding often and prolifically, the rodents and the birds in particular would undergo population explosions at the site of a bamboo flowering. Among the larger and less prolific species of
animal, migration would swell the numbers. Elephants and deer and pigs would get wind of the bounty, or stumble onto its fringes in their hungry wanderings, and come crowding in. With ever more mouths to feed, satiation would be impossible. That problem is obviated by the second component of the strategy: synchronized delay. Between one massive reproductive effort and the next,
the bamboo species pauses stubbornly–for, oh, 32 or 48 or 120 years–while the excess predators die of starvation or old age, or else wander away again, seeking some other banquet. Not until decades later, when the predator populations have crashed or thinned, when those seed-eaters that remain are sparse and unsuspecting, does the internal timepiece again waken each bamboo plant
to the mandate of procreation.
Janzen’s hypothesis is that bamboos wait so long to flower as a means of escape, across time, from their pestilential admirers.
Notwithstanding the enthusiasm of authorities like Porterfield and Farrelly, I think it’s healthy to view “the universal provider” from Janzen’s perspective. Bamboo may be the god of the Piyoma, and the staff of life in India, and the foundation, walls, and roof of traditional Javanese civilization, but there’s no grounds for assuming that such veneration is mutual, or that the
benefits flow equally in both directions. We’re not talking about a dotingly interdependent relationship, like the one between humans and, ugh, dogs. Although some species of bamboo are being grown in plantations or conserved as a forestry resource in some countries, even the ebullient David Farrelly warns that, in other places, the big stands of bamboo have been whacked down and
used up, converted to building materials and paper pulp and chopsticks and twine, the landscapes they once graced now given over to field crops or cow pasture or urban sprawl. Those canebrakes in the southeastern United States, for instance–Farrelly calls them “drastically reduced,” though he doesn’t cite numbers. And the South American species Guadua
angustifolia, one of the world’s most durable and versatile bamboos, has been so perfervidly but shortsightedly appreciated, so heavily harvested without replanting, that according to Farrelly it faces “virtual economic extinction by the year 2000.”
Of course “virtual economic extinction,” whatever that means, isn’t synonymous with biological extinction. Are we presently losing whole species of bamboo? Frankly, I don’t know. The sources I’ve seen don’t address that important question. I won’t presume to tell you that our planet’s bambusoid diversity is at risk, though it may well be. But we might want to bear in mind that
bamboo’s very usefulness, its international recognition as a dependable resource, its huge role in meeting humanity’s needs and wants, and the almost deified status it has assumed in some places and times, all represent an ambivalent sort of renown for a group of plants among whom survival and procreation, not worship and transubstantiation, are the standards of success.
Human history teaches us that godliness can be a fearful burden, yes? If there were a religion of grass, I suspect, the crucifixes would be built of bamboo.
|