Both these books are about the use of native plants by people living in the Amazon basin, but beyond that they could hardly be more different. One River is an adventure story, a biographical account of two plant explorers, Richard Evans Schultes, Oakes Ames Professor of Economic Botany at Harvard, and his student and kindred spirit, Timothy Plowman. Wade Davis, another student of Schultes and a traveling companion of Plowman, describes the experiences of the two scientists as they explore uncharted jungles, encounter unknown tribes, and find botanical specimens whose existence had been unanticipated. Schultes is likened to his hero, the great British botanist Richard Spruce, who for fifteen years in the 1850s and 1860s explored some of the same parts of the Amazon. Nigel Smith’s book, while competently written in standard academic language, is a comparatively dry documentary without any stories of personal discovery. It is particularly concerned with the Amazon of the future, whereas One River revels in an Amazon of the past that now, in the 1990s, has all but ceased to exist.

The upper Amazon visited at mid-century by Schultes and Plowman is wild, remote, and virtually inacces-sible, sparsely inhabited by small tribes speaking mutually unintelligible languages and practicing shamanistic rituals employing concoctions made from plants unknown to science. The lower Amazon described by Smith late in the century is a thoroughly tame place inhabited by mestizos who have lost all vestiges of their indigenous roots and who are integrated, albeit marginally, into the modern global economy. It is an Amazon in which the forest and its teeming life have long since been extinguished to make way for croplands and livestock. One has to stretch the imagination to fit the two pictures together. Yet such striking juxtapositions help us to grasp the reality of the Amazon today: it is a continent-sized region at the crossroads between a mysterious and often violent past and a mundane future in the modern economy.

Most of the post-Columbian history of the Amazon is one driven by the greed and bigotry of ruthless exploiters and opportunists—conquistadors, priests of the Spanish Inquisition, plantation owners who made fortunes from slave labor, and, finally, the participants in the unbridled mania of the rubber boom. The Amazon attracted people with an overbearing cultural arrogance combined with a remarkable capacity for ethical blindness, an attitude based on the irrational and untenable pretext that Indians were subhuman. Few of them treated their horses as badly as they treated the Indians, yet most failed to grasp the hypocrisy in that inconsistency. Priests were hardly better than the fortune-seekers in their intolerance. Whereas the exploiters butchered or enslaved the Indians as subhuman beings, the priests demanded that they accept the edicts of the Catholic Church imme-diately and without question. Those who resisted were placed in stocks, whipped, or worse.

The first Europeans to experience the vastness of the Amazon were the soldiers of fortune who, in 1542, accompanied Francisco de Orellana on a quest for El Dorado. The group set out from Quito (now the capital of Ecuador), crossed the eastern Andes, and descended the Amazon from its headwaters to its mouth in an astonishing transcontinental odyssey that was not to be matched in Africa for another 320 years.

We would have no eyewitness record of the indigenous settlements found by these adventurers along the Amazon were it not for the account of Friar Caspar de Carvajal, a priest who accompanied Orellana. Carvajal reported passing dense settlements that stretched for miles along the riverbank. At the mouth of the Tapajos, a major tributary of the lower Amazon, over two hundred canoes containing twenty to thirty warriors each met Orellana’s flotilla, while a similar number of warriors shouted defiance from the shore. A population that could muster ten thousand warriors had to be several times larger than that, whereas contemporary settlements of Amazonian Indians only rarely surpass a few hundred people.

Many modern writers have dismissed Carvajal’s account as highly embellished because no subsequent travelers reported populations of similar magnitude. For example, in 1689 Friar Samuel Fritz saw no people at all during six days’ travel on the Amazon below the confluence of the Urubu River—a stretch in which Carvajal claimed the Orellana expedition had to fend off numerous attacks. Some anthropologists, noting the generally poor quality of Amazonian soils, have asserted that the region could not possibly have supported dense human concentrations.

Independent evidence vindicating Carvajal’s credibility has recently come to light in a series of remarkable excavations directed by the archaeologist Anna Roosevelt. It now appears that the lower Amazon has been settled for at least ten thousand years. At a number of sites, archaeologists have discovered enormous man-made mounds, vast middens containing evidence of early cultivation of plants and expanses of terra prieta (black earth) produced by Indians and extending over several square kilometers. It can no longer be doubted that the Amazon was a major cradle of a civilization that appeared only a short time after those of China and the Middle East. Revised estimates of the pre-Columbian population of the Amazon run as high as 15 million, a figure that has not been surpassed to this day.


If one is to believe this reconstructed history, there has to be an explanation for the complete absence of any eyewitness accounts of dense human populations in the Amazon after Orellana. Most likely, what happened was that millions of Indians fell prey to European diseases introduced by Orellana’s party—smallpox, tuberculosis, influenza, and perhaps others. While horrific, the depopulation of the central Amazon in the sixteenth century was nothing unusual. Similar demographic collapses, typically amounting to 90 percent of the pre-contact population, occurred throughout the New World following the arrival of Europeans.

Enabling large populations to accumulate along the Amazon was a set of circumstances parallel to those that favored population growth in the flood plains of other great tropical rivers, such as the Ganges, Brahmaputra, Irrawaddy, and Mekong. Like the Amazon, these rivers arise in steep mountains and carry large quantities of freshly eroded sediment. All are subject to seasonal flooding that creates a highly predictable cycle of renewal.

Such rivers pass through three hydrological zones, and in the case of the Amazon, these zones are especially pronounced and distinct. In the headwaters, flooding follows exceptionally heavy rains and is therefore occasional and of short duration. For example, at the research station near the foot of the Andes in Peru where I spend part of each year, I know that a flood will crest approximately thirty hours after the onset of a heavy rain. For all but a few days of the year, however, the flood plain is above water.

Far downstream, after many tributaries have joined to create a major river, the flooding becomes a much more regular response to the onset and termination of the rainy season, although it takes a considerable period of time for the flood to reach its peak. At Iquitos in Peru, for example, the Amazon crests in May, one or two months after the rains have begun to taper off in the headwaters. The water simply takes that long to travel hundreds of miles. Another thousand miles downstream at Manaus, Brazil, the crest passes in July during the local dry season. In between, near Tefé, Brazil, the seasonal rise and fall is greatest, amounting to almost forty feet. Finally, as the river approaches the Brazilian port city of Belem near its mouth, the channel widens to as much as one hundred miles, dissipating the annual flood. There, the hydrological rhythm becomes tidal rather than annual, and different plants replace those that line the banks upstream.

In doubting the capacity of the Amazon to support intensive agriculture, anthropologists overlooked the great flood plain—called the varzea—that stretches from Iquitos in Peru nearly to Belem, a distance of some 1,800 miles. The soils of the uplands are indeed infertile, but the flood plain is rejuvenated annually as a surging torrent reworks the underwater topography in a process that also helps purge weeds and pathogens. Moreover, the system operates like clockwork, largely freeing farmers from the caprice of the local weather system.

The generous agricultural potential of the varzea provided a propitious setting for the early domestication of quick-maturing annual crops. Smith speculates that sweet potatoes may have been cultivated on the flood plain as long as ten thousand years ago. Other root crops, among them cocoyam, were among the earliest cultivars, followed somewhat later by manioc, now the leading staple of most Amazonian cultures. Maize did not enter the picture until later, spreading eastward from the Andes between six thousand and four thousand years ago.

Prehistoric settlement patterns in the Amazon may thus have been similar to those in the Old World, where early civilizations arose and flourished in the flood plains of the Nile, Euphrates, Indus, and Mekong. Away from the flood plains, in the vast interfluvial hinterlands, human beings pursued a different way of life, epitomized by the Waorani of eastern Ecuador, with whom Wade Davis spent a year in the 1970s.

The Waorani, like the Yanomami of northern Brazil, lived in scattered multifamily settlements composed of closely related members of a kinship clan. When first contacted by outsiders in the 1950s, the entire tribe consisted of no more than five hundred men, women, and children living within a fiercely defended territory of 7,500 square miles. This small population was further subdivided into four kin groups, all of them mutually hostile and none of them certain where the others lived. Using shifting cultivation, and moving their settlements every year or two, the Waorani left an almost invisible footprint upon the land, depleting neither the forest nor its game. After all the Waorani groups had been identified and “pacified,” the Ecuadorian government established a reservation for them amounting to 0.5 percent of their former territory.


Following the catastrophic depopulation of the sixteenth century, there ensued three centuries during which the rest of the world largely ignored the Amazon. Missionaries established outposts here and there along navigable rivers, while a few adventurers, fortune seekers, and the odd biologist explored the unknown territory that was to be found by following the river’s countless tributaries. European settlement concentrated along coasts and in the comfortable and salubrious highlands of the Andean countries.

When the renowned naturalist Alfred Russell Wallace visited Manaus in the 1850s, it was a sleepy village that subsisted largely on the export of turtle egg oil, which was used for light and cooking. In a memorable passage, Wallace depicts a festive scene in which local mestizos stomp with great exuberance on canoe loads of eggs to initiate the process of separating the oil from the white and shells. The turtle egg oil business soon petered out, as have so many other Amazonian booms, because overexploitation decimated a once-teeming population of giant river turtles. Today, the species teeters on the brink of extinction.

Soon thereafter, the economy of the lower Amazon began to pick up as a soaring European market for chocolate unleashed a boom in cacao, the source plant of chocolate. It had been discovered that cacao grew well in the higher portions of the varzea, where the flood-tolerant trees could profit from the rich soil. Europeans flocked to the Amazon to set up plantations and drew in thousands of Brazilians of mixed descent as labor.

The same period saw the beginnings of another boom, based this time on the milky juice, or latex, of a number of indigenous plants and trees, but primarily the rubber tree, Hevea brasiliensis. The Indians called the coagulated juice “caoutchouc” and made rainproof sheets and vessels from it. Arawakians played games with balls that strangely bounced and soared. Thomas Jefferson and Benjamin Franklin believed the plant grew in the East Indies and called the material India rubber, when in fact it came from the Amazon. Already the King of Portugal had established a flourishing business producing rubber shoes, capes, and bags. In 1823, a Scotsman, Charles Macintosh, discovered that rubber could be dissolved in naphtha and then made into a pliable coating for fabric, thereby inventing the world’s first raincoat.

The rubber of these times had its limitations. In normal weather it served well, but in the cold it cracked like porcelain and in the heat of summer it became flaccid and sticky. Then, in 1839, a Bostonian, Charles Goodyear, discovered that rubber heated with sulfur became tough, pliable, and relatively impervious to swings in the weather. The vulcanization process he invented transformed rubber from a minor commodity to an essential component of the industrial age. Over the next thirty years, production of wild rubber in Brazil soared from 31 to 2,600 tons.

By 1898, more than fifty American companies were manufacturing automobiles. Oldsmobile, the first to be successful, sold 425 cars in 1901. Within the decade, Henry Ford was building Model Ts, of which fifteen million were eventually sold. The demand for rubber generated by the burgeoning automobile industry drove the price into the stratosphere, so that by 1910, rubber accounted for 40 percent of Brazilian exports. At the height of the frenzy, five thousand men a week headed up the Amazon to seek their fortunes.

The best rubber groves lay in the headwaters of Amazonian tributaries carrying such names as Japurá, Juruá, Purus, and Madre de Dios. These headwaters drained an almost unknown region preserved in isolation on the west by the forbiddingly steep eastern flank of the Andes, and on the east by impassable rapids and cataracts. “Almost overnight,” Wade Davis writes, “a forgotten land of jungle and rivers became the destination of an army of dreamers and thieves, merchants and their barbarous lackeys who in time would be known to the Indians simply as ‘the people eaters.”‘

To make a profit the merchants had to establish exclusive control over enormous territories…. They accomplished this with private armies, gunboats commissioned in Liverpool, and enough loose capital to buy off any government official who stood in the way. Once their lands were secure, they needed workers, thousands of them…. The industry…soaked up entire tribes of Indians into an atrocious network of debt peonage from which there was no escape.

Among the most notorious rubber traders was Julio Cesar Arana, a Peruvian who began his career as a peddler selling straw hats in somnolent Andean towns. Restless and ambitious, he headed for the Amazon, where he set up a trading post on the Huallaga River in a region now notorious as a center of production of coca leaf. He catapulted himself into a position of power by observing that the price of rubber was rising steadily and by astutely perceiving the opportunity this represented. His scheme was to sell provisions to rubber tappers on credit, requiring that the debt be paid in rubber at the going price on the date the debt was incurred. So rapidly was the price of rubber rising that he realized an average profit of 400 percent.

By 1905, he owned over 12,000 square miles of the Putumayo watershed forming the border between Peru and Colombia. To exploit the rubber resources of a region the size of the state of Maryland, Arana needed labor, lots of it. The region was well populated by Indians, who, having no interest in laboring for outsiders, fled into the forest at the approach of a boat.

Arana decided that the solution was terror. He began by importing as overseers criminals and deviants who arrived in his debt. Rubber traders were legally permitted to “civilize” Indians. Using this pretext, Arana’s men staged attacks at dawn, trapping whole villages within their long houses and then offering the men gifts that were used to trick them into enslavement. Workers who failed to deliver their quotas were beaten or maimed. They submitted because their wives and children were held hostage. Attempts to escape were punished by torture and death. Women were fair game. Some were held in stocks for weeks, available to anyone.

In the twelve years that Arana ran his business on the Putumayo, he exported over four thousand tons of rubber, for which he received more than $7.5 million. During those years, the indigenous population of the Putumayo fell from 50,000 to fewer than 8,000. Arana’s sadistic lieutenants killed out of boredom. “For each ton of rubber produced,” Wade Davis writes, “ten Indians were slaughtered and hundreds left scarred with welts and wounds that became known throughout the Northwest Amazon as la marca Arana, the mark of Arana.” Three hundred fifty years after the arrival of Orellana, the rubber boom had completed the depopulation of the Amazon.

By 1920, the bubble had burst. Efficiently grown plantation rubber from the Far East had taken over the market, and the flow of natural rubber from the Amazon had dwindled to a trickle. Missionaries of many stripes moved into the vacuum left by the departed rubber barons, and began to proselytize among the decimated tribes of the headwaters region, ushering in a new era of benign paternalism.

Years later Schultes chanced to visit a mission on the Río Igaraparaná, a tributary of the Putumayo. As he disembarked and climbed up the river bank, dozens of excited Witoto children rushed up to greet him, all dressed in white uniforms. Behind them were two nuns, cloaked in white habits. That evening the priest, a garrulous and mildly irreverent sort who was relieved that the visitor had been Schultes and not his bishop, took his guest to see a locked room on the ground floor of a solid stone building. Inside, as a dim shaft of light penetrated the gloom, Schultes could make out a row of stocks. Chains and bars protruded from the walls, and a row of hooks hung from a rafter, chilling reminders of Arana’s day and of a history all survivors of that particular holocaust would like to forget.

Schultes’s introduction to the Amazon came in 1941 after he won a fellowship from the National Research Council to investigate the botanical source of arrow poison. By then he had already completed his doctorate at Harvard and earned a reputation as an ethnobotanist for work on peyote and for his discovery of Mexican hallucinogenic mushrooms that proved to contain LSD. The toxicity of curare, the poison used by South American Indians to coat arrows and darts, had been renowned since the eighteenth century. As early as the 1850s, the famous French physiologist Claude Bernard had shown that the poison blocked neuromuscular transmission, a discovery that led to immediate applications in the alleviation of conditions causing severe muscular pain and contractions.

Arrow poison was a vital ingredient of the industrial world’s pharmacopeia, but it produced uneven results, largely because the preparations were crude and inconsistent. Several botanical collectors claimed to have discovered the source plant, but each had identified a different species, so there was considerable confusion. Meanwhile, the essential ingredient had been isolated and identified in 1935 as d-tubocurarine, so more was known about the chemistry and pharmacology of arrow poison than its botany. Not long afterward, in 1942, curarine was used by Harold Griffith in Montreal to induce muscular relaxation in patients undergoing anesthesia, making possible the use of greatly reduced doses of anesthetic, and thereby lowering the attendant risk. Over the next fifty years, d-tubocurarine would save more lives than had ever been lost to curare in tribal warfare.

Eventually Schultes would discover no fewer than fourteen plants that were sources of curare, vindicating many of the claims made by his predecessors. But while he was in the field, word reached him that the United States had entered World War II, and that he was wanted by the US embassy in Bogotá.

At the opening of the World War, the United States found itself in a dire predicament. The Japanese had recently occupied much of Southeast Asia, which, in the last year of peace, had supplied 99 percent of the world’s rubber. At the time, the US was producing 70 percent of the world’s automobiles and consuming over half the global production of rubber. The war effort would require vast amounts of rubber: half a ton for each Sherman tank, a ton for each heavy bomber; rubber for every valve, seal, and inch of wiring; rubber for conveyor belts, hydraulic systems, gas masks, rain gear. There was no substitute. A synthetic had been invented, but its inferior qualities were inadequate for many applications, and production in 1939 was a meager 2,500 tons, less than one percent of what was needed.

To find solutions to the rubber crisis, President Roosevelt established the Rubber Reserve Company, for which Congress appropriated $140 million. Schultes was called to Washington and handed the assignment of scouting potential sources of natural rubber in the northwestern Amazon. In One River, Davis gives a gripping account of Schultes’s descent of the Río Apaporis, a blackwater tributary which arises in the foothills of the Andes and flows east for 1,350 miles before joining the Caqueta at a point still hundreds of miles above its confluence with the main trunk of the Amazon.

In 1943, the Apaporis River flowed through uncharted territory devoid of human settlements. The best available maps were largely fictitious, depicting rivers and mountains in places where there were none, and vice versa. The Indians feared the river; its gorges and cataracts, they said, were haunted by malevolent spirits. Schultes arranged for a flight that allowed him to inspect the river from the air. He saw that impassable rapids blocked access to the headwaters but defined a starting point below which the river appeared to flow placidly for several hundred miles. Then, abruptly, the river narrowed from perhaps half a mile to one hundred feet before dropping seventy feet over the cataract of Jirijirimo into a chasm nine miles long and fifty feet wide, encased in towering rock walls.

Schultes’s plan was to launch a riverboat below the upper falls and survey the navigable portion of the valley to a point just above the Jirijirimo cataract. From there, the party was to employ an outboard motor to return to the starting point. But plans do not always unfold as conceived. By the time Schultes and his Indian companions reached the turnaround point, their food was running low and their gasoline supply was nearly exhausted. Returning upstream was not a practical option. Miraculously, they succeeded in making a portage around the cataracts of Jirijirimo and Yayacopi and continuing downstream all the way to the Caqueta. One River is well worth reading if only for the account of this remarkable journey.

Schultes discovered in the Apaporis the richest stands of Hevea brasiliensis in the Colombian Amazon, estimated to contain sixteen million trees. The Rubber Reserve Company set up an operation to extract rubber but, in the end, Amazonian rubber had only a small part in satisfying the wartime needs of the US, which eventually were met largely by improved forms of synthetic rubber. Even at the peak of the boom around 1910, total South American rubber production never exceeded 50,000 tons, which by the 1940s amounted to only one fourteenth of US consumption.

During his twelve years in the Amazon, Schultes lived with more than twenty Indian tribes and collected over 20,000 plant specimens, including more than three hundred species new to science. His botanical exploits are legendary, but the Amazon Schultes explored in the 1940s and 1950s has all but vanished. The colorful tribes and arcane rituals he observed will be historical curiosities read about by South American schoolchildren, just as students in the US read about Indian wars and crossing the plains in covered wagons.

The Amazon of the future will little resemble the Amazon of the past. Already the children of nearly every tribe receive instruction in Spanish or Portuguese, and as the younger generation crosses the language divide, so will it cross the cultural divide. Literate, and aware of the larger world around them, the young will slip unnoticed into a sea of brown-skinned people. They will drink beer, watch television, and be fans of the national football team, just like everybody else.

Airplanes, radios, and reliable outboard motors have all but eliminated the Amazon’s wildness. Just a few months ago I was invited to the Amazon to instruct Latin American graduate students in biological field techniques. The students represented the entire continent: Mexico, Guatemala, Costa Rica, Colombia, Venezuela, Bolivia, etc. We met at a tourist lodge some three hours by speedboat from Iquitos, Peru. With 300,000 inhabitants, Iquitos is perhaps the largest city in the world not connected by road to anywhere else.

The forest around the lodge was serene and intact, having so far been spared the ravenous wave of logging that is currently sweeping the Amazon. And yet it was strangely silent. The expected sounds of parrots, macaws, and monkeys were missing. Once I heard a toucan in the great distance, but that was the only large forest bird I detected in nearly a week.

Sadly, the “empty forest syndrome” that afflicts the entire Iquitos region has become the norm over much of the Amazon. Rubber tappers subsisted on game and often little else. Commercial hunting for meat and trapping for hides were actively pursued in the 1960s and 1970s. Today thousands of loggers and miners, agents of the current bonanzas, are mopping up any animal populations that survived the earlier booms; protein-hungry workers track down the last peccaries, deer, and monkeys. Soon, I fear, the entire Amazon will be an empty forest, save for a handful of inadequately protected parks and reserves. In merely a century, a continent-sized wilderness inhabited by diverse and unknown tribes is well on the way to cultural homogenization in the midst of a dying forest that awaits only the coup de grâce of the chainsaw.

Nigel Smith has great affection for the caboclos (settlers) of the varzea and he is understandably fascinated by their intimate ties to the rhythm of the river. He makes a nostalgic plea that native biodiversity continue to serve as a “cornerstone for agricultural intensification.” I would argue to the contrary that the caboclo lifestyle is foreordained to go the way of spears and stone axes. We should not forget that pioneers living on the North American frontier two hundred years ago gathered fruits and nuts from the forest, selected the proper wood to be used for dozens of specialized purposes, and treated their ills with poultices and teas made from native plants. But who among us now still lives by the lore of two hundred years ago, however rich and insightful it may have been at the time?

Reality overtakes nostalgia in Smith’s final chapter, where he reluctantly acknowledges the inevitability of a future driven by global markets, a future in which specialization will replace diversification, machines will replace muscles, and investment will replace the resourcefulness of the pioneer. What will happen to the Amazon then?

I agree with Smith that the promising but largely untapped agricultural potential of the flood plains will be the object of the next Amazonian bonanza. A preview of the varzea of the future can be seen from an aircraft flying over the flood plain of the lower Mississippi. No trees are in sight. The scene is a checkerboard of large agricultural fields punctuated only by waterways and fish culture ponds. As agribusiness supplants subsistence farming, the Amazon’s population, already two thirds urban, will become even more so.

And what will become of the Amazon’s fabled biodiversity? The region’s vast interfluvial hinterlands remain little altered today, except for the scars of failed development projects undertaken in the misguided belief that the giant trees presaged a bounteous harvest. Right now the governments of nearly all the Amazonian countries are eager to reap the standing capital of the virgin forest. These policies point to a future in which forests containing a thousand species of trees will be converted to monotonous tree farms to supply an insatiable global market for forest products.

Will the world’s greatest tropical forest be reduced to a vestige, with the demise of countless species of plants and animals, or will substantial portions of it be allowed to remain intact as a global reservoir of biodiversity? Politics both in the Amazonian countries and in the powerful nations to which they export will determine the answer. The politics of the present are not encouraging, but attitudes are changing and one can hope they will change for the better before it is too late.

This Issue

January 20, 2000