Another authoritative study also focused on the surprising microbial vigor and utility for agricultural purposes of ADEs, noting a further connection with the managed use of fire. “Fire contributes charcoal and ash, which increase soil pH, thereby suppressing aluminum activity toxic to plant roots and soil microbiota.”30
What is more, fire increases the capacity of the soils to retain nutrients, thus maintaining a “synergistic cycle of continued fertility.”31
In summary, concedes Professor WinklerPrins, the microbial complexes associated with ADEs are “poorly understood” and “quite mysterious actually.”32 Likewise, even the authors of the shitscape/middenscape theory of ADE formation admit that “despite the importance of research on terra preta, we still lack a firm understanding of the specific formation processes that led to the diversity inherent in these anthrosols.”33
Yet all this mystery, all this effectiveness, all this efficiency, and all these remarkable contributions to welfare, we are asked to believe, came about as incidental by-products of human activity? They just happened—without any planning, or deliberation, or design at all?
I could see immediately why such ideas would give comfort to archaeologists whose roller-coaster ride thus far has taken them from a position where they had convinced themselves and their students that there could never have been any cities in the Amazon, to a position where they must now accept that the prehistoric rainforest once teemed with cities. This in itself has been a traumatic enough paradigm shift. I’m therefore not surprised that most archaeologists remain unwilling to go the extra mile needed to view terra preta—that “miraculous” agent of fertility—as the product of deliberate, ingenious, organized, focused, scientific activity. It causes far less cognitive dissonance, for so naturally conservative and cautious a discipline, to conclude instead that it was the waste and refuse of those previously contested Amazonian cities with their very large populations that had accidentally fertilized the land and made possible the otherwise anomalous boost to agricultural productivity that had kept the stomachs of the otherwise anomalous urban populations full.
But isn’t it much more likely that all this happened the other way around?
Surely it makes no sense that the large populations came first. If they did, how did they feed themselves while enough shit and fish bones were being accumulated to create the first patches of terra preta? Isn’t it more logical that the settlement and expansion of human populations in the Amazon was a planned affair in which the spread of terra preta was a precondition for the development of large settlements rather than a consequence of it?
Professor Balée, not an archaeologist, seems to be thinking somewhat along these lines when he cites the bizarre microbial differences between ADEs and the original, unenhanced soils that surround them as evidence for a deliberate human “contribution to microbial diversity in the Amazon, a remarkably intriguing and still living, even evolving legacy of the pre-Columbian Dark Earth people.”34
REMARKABLE AND PRECOCIOUS SCIENCE
AS WITH SO MUCH ELSE that concerns the Amazon, the issue of when, exactly, terra preta first began to be created continues to be fogged by confusion and uncertainty.
A casual glance through the scientific literature might leave the reader with the impression that these exceptionally fertile anthropogenic soils are a phenomenon of the past 3,000 years only—with the great bulk of terra preta creation taking place between about 1,000 years ago and the time of the European conquest.35
Look closer, however, and you will discover that many of the same authorities are tiptoeing around the edges of another mystery here.
For example, while reemphasizing their satisfaction with the idea that Amazonian Dark Earths are “produced by human habitation but unintentionally,”36 and noting that ADE formation “ceased in most, if not all, parts of Amazonia during the early Contact period,” Eduardo Neves and his colleagues concede that “the initiation of ADE formation has been more difficult to explain so far.”37
They choose to focus on the period from around 2,500 to 2,000 years ago but caution that earlier sites may have disappeared due to the dynamic landscape processes of the Amazon, or perhaps because “the soil organic matter in most older ADE sites has been mineralized, leaving only inorganic artifacts behind, without coloration of the substrate by organic matter, and thus, early sites are under-represented.”38
But by no means all of the earlier sites have disappeared. Enough of the older plots remain for several of the leading authorities to agree that 2,500 years ago is nowhere near the beginning of the story. Neves himself accepts the existence of much older ADE sites, notably “the sites of the so-called Massangana phase … dated ca. 4,800 BP.”39
These sites, which are about 300 years older than the orthodox date for the construction of the Great Pyramid of Giza, are located in southeast Amazonia in the Jamari River area. Unfortunately, they are no longer accessible, having been flooded by the construction of the Samuel hydroelectric dam.40 It seems, however, that there are even older ADEs. In the Proceedings of the Royal Society, for example, Neves and others report Black Earths that are between 5,000 and 6,000 years old.41 Elsewhere—in no less august a journal than Nature—we read of ADEs that “are thought to be 7000 years old.”42
Nor does the trail leading back to humanity’s time of amnesia quite fade from view even there. Specialists from Cornell University’s Department of Crop and Soil Sciences, joined by Eduardo Neves and citing his “unpublished data,” conclude in the Journal of the Soil Science Society of America that the man-made Dark Earths of the Amazon in fact date back as far as 8,700 years ago.43
And again, Neves’s own caution must surely apply—that even older sites than this may very well once have existed but have disappeared with the passage of time.
Given the incredible longevity of this soil and its extraordinary ability to regenerate its own fertility through microbial action, it is by no means beyond the bounds of reason to suppose that plots of terra preta dating back to the last Ice Age might still exist somewhere in the millions of square kilometers of the rainforest that have never been investigated by archaeologists at all.44
What is certain, however, is that a remarkable and precocious skill and competence in soil science—“exemplary agronomy” in Professor David Wilkinson’s phrase—leaves its fingerprints in the Amazon at least 8,700 years ago. After that (and for how long before that we do not know) its use becomes integrated into the harmonious and successful lifeways of ancient Amazonian civilization. This civilization thrives for millennia, long outlasting ancient Egypt and ancient Mesopotamia, doing very well for itself and for its people in just about every possible way, until the catastrophe of European contact that not only subjects it to genocide by sword and by epidemic, but also conspires to deny its very existence for centuries thereafter.
Reader, please note—when I speak of an “ancient Amazonian civilization” I am not under any circumstances claiming that this was the lost civilization I have spent much of my working life trying to track down! My suggestion, rather, is that, in weighing what happened in the Amazon from the Ice Age until the European conquest, we may find that certain striking anomalies such as the mysterious Australasian genetic signal, and indeed the Amazonian Dark Earths themselves, bear the fingerprints of that world-exploring, world-encompassing, world-measuring lost civilization of prehistoric antiquity. More specifically, the proposition we are presently considering in this context is that the settlement and expansion of human populations in the Amazon was a planned affair in which the spread of terra preta was a precondition for the development of large population centers rather than a consequence of it.
It was, in other words, not something random at all but an integral part of a carefully thought-out project.
GARDENING EDEN
FURTHER INTRIGUING HINTS THAT SOME sort of intelligent, guided project was mounted in the Amazon thousands of years ago are to be found in recent studies of the species of trees that pop
ulate the rainforest. These studies demonstrate that far from being a “pristine” natural environment, the Amazon is largely a human creation.
Anna Roosevelt, whose sometimes radical views we’ve already encountered, criticizes other scientists for assuming—all too often—that the Amazon’s forests are entirely works of nature “without conducting research to exclude a human influence.”1
When that research is done, it turns out that while “Amazonian forests in different regions differ significantly from one another in topography, climate, geology, hydrology, structure, seasonality, and history,” they nonetheless “often resemble each other” in showing a “pattern of unexpected dominance and density of a small group of plant species. This pattern has been found wherever Amazon forests have been inventoried and has yet to be explained by natural factors.”2
The best current estimate is that the Amazon is presently home to about 16,000 woody tree species. Out of this total, however, “only 227 hyperdominant species dominate Amazonian forests.”3 These so-called oligarchs (from the Greek for “rule by a few”) “make up only 1.4% of all the Amazon forest species but almost half of the trees in any given forest.”4
In 2017 a large international team of ecologists and archaeologists, led by environmental science researcher Carolina Levis of Wageningen University in the Netherlands, completed a study looking into this peculiar pattern of distribution. What immediately stood out in their data was that, among the oligarchs, “domesticated species are five times more likely than nondomesticated species to be hyperdominant.”5
Moreover, in almost every case where clusters of hyperdominants were inventoried, ancient archaeological sites were found among them6—a correlation so frequent and reliable that the presence and concentration of oligarchs could, in theory, be used to “predict the occurrence of archaeological sites in Amazonian forests.”7
The team’s detailed analysis, published in Science, therefore concludes that “modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples. … Detecting the widespread effect of ancient societies in modern forests … strongly refutes ideas of Amazonian forests being untouched by man. Domestication shapes Amazonian forests.”8
We’ve seen that the question of exactly when human beings first arrived in the Amazon remains to be settled. So, too, does the question of exactly when they began to domesticate trees. The team’s results suggest that “past human interventions had an important and lasting role in the distribution of domesticated species found in modern forests, despite the fact that the location of many archaeological sites is unknown.”9 On present evidence, however, adds Levis, all that can be said with certainty is that at some point “more than 8,000 years ago,” Amazonian people were already focusing attention on certain trees that were particularly useful to them.
They really cultivated and planted these species in their home gardens, in the forests they were managing.10
Among the favored species mentioned in the Science paper, now all hyperdominant, are Bertholletia excelsa (the Brazil nut tree), Inga edulis (“Ice-Cream Bean,” a fruit tree), Pourouma cecropiifolia (“Amazon Grape,” a fruit tree), Pouteria caimito (the abiu, a fruit tree), and Theobroma cacao (the cocoa tree—chocolate).11
Other prized Amazonian species domesticated in ancient times include the açai palm and tucuma palm, the peach palm, the Cupuaçu tree, the cashew tree, and the rubber tree.12
A MAJOR CENTER OF CROP DOMESTICATION
AS I RESEARCHED THIS MATERIAL I was initially surprised to learn that cocoa trees and rubber trees, both of which I’d wrongly believed were indigenous to and had been domesticated in Mexico, were in fact originally South American species and had been domesticated in the Amazon. I was equally surprised to learn that capsicum—chili peppers, red and green bell peppers, et cetera—which I had again wrongly thought were Mexican in origin, had likewise first been domesticated in the Amazon.13
Indeed, though often overlooked, Amazonia has rightly been described as “a major center of crop domestication” on a global scale.14 Prior to the European conquest, according to Charles R. Clement of Brazil’s National Institute of Amazonian Research, “at least 83 native species were domesticated to some degree, including manioc, sweet potato, cacao, tobacco, pineapple and hot peppers, as well as numerous fruit trees and palms, and at least another 55 imported neotropical species were cultivated.”15
Pineapples! There was another surprise for me, as I had (again wrongly) always assumed that these tropical fruits grow on trees and had their origins in some Pacific archipelago, perhaps Hawaii. In fact, the pineapple plant with its long, spiky leaves, is not a tree. It grows close to the ground (with each plant producing a single pineapple), belongs to the Bromeliad family, and is indigenous to, and was first domesticated in, the Amazon rainforest.16
There is no firm information on when domestication was undertaken, but in Charles Clements’s view, “The widespread distribution of the pineapple in the Americas at the time of the European conquest, the diversity and quality of the cultivars, not surpassed after one century of modern, intensive breeding, the diversity of uses, the economic and cultural importance of the crop, all point to a very ancient domestication.”17
Out of the 83 crops native to Amazonia and the 55 “exotic” ones, a total of 138 crops in all, Clements and his colleagues classify 52, including the pineapple, as fully domesticated. Of these, 14 (27 percent) are fruit or nut trees or woody vines. Among the 41 crops classified as semi-domesticated, 35 (or 87 percent) are fruit or nut trees or woody vines. Among the 45 crops classified as incipiently domesticated, all but 1 are fruit or nut trees:18
Overall, 68% of these Amazonian crops are trees or woody perennials. In landscapes largely characterized by forest, a predominance of tree crops is perhaps not surprising. Nonetheless, the most important subsistence crop domesticated in Amazonia is an herbaceous shrub, manioc, and several other domesticates are also root or tuber crops, most of which are adapted to savanna-forest transitional ecotones with pronounced dry seasons.19
Think of it. The rainforest was coaxed, shaped, and transformed by what can only be described as scientific practices into a vast garden of useful and productive trees. But trees alone cannot feed large populations, so the prehistoric domestication program was extended on a massive scale to include agricultural species that were then successfully incorporated, through the use of terra preta, into the Amazonian ecology.
THE MANIOC CONUNDRUM
MANIOC, THE KEY STAPLE, “THE most important food crop that originated in Amazonia,”20 and on which the majority of the population of the Amazon still depend today,21 is of particular interest for a number of reasons. Molecular analysis has confirmed that this woody shrub, cultivated for its edible roots, was domesticated in the Amazon basin, “most likely in the savannas, the Brazilian Cerrado, to the south of the Amazon rainforest,”22 and more specifically “in northern Mato Grosso, Rondônia and Acre states, in Brazil, and adjacent areas of northern Bolivia. Domestication must have started before 8,000 BP, as that is the earliest date reported from the Zana and Ñanchoc valleys of coastal Peru.”23
Unlike the Amazon itself, large parts of which remain inaccessible to archaeologists, these two coastal Peruvian valleys have been well studied, yielding, as well as manioc, “evidence for radiocarbon-dated human cultivation of squash (9240 and 7660 yr B.P.), peanut (7840 yr B.P.), quinoa (8000 and 7500 yr B.P.), and cotton (5490 yr B.P.).”24
What is notable, however, is that all of these crops had already been domesticated elsewhere before being grown in coastal Peru.25
As with cocoa and chilies, I’d long been under the impression that the squash plant (cucurbita) was first domesticated in Mexico around 10,000 years ago, and indeed there is archaeological evidence to support this.26 But now here it was turning up in Peruvian coastal valleys 9,240 years ago, and not only there but at similar dates in the nearby sites of Paiján and Las Pircas.27 An authorit
ative study published in Science suggests that these cultivated Peruvian squash plants may have been from a line that had originally been domesticated not in Mexico but in “southwestern Ecuador and the Colombian Amazon” as early as 10,000 to 9,300 years ago.28
What about the peanuts cultivated in the Zana and Ñanchoc valleys 7,840 years ago? They, too, it turns out, were domesticated east of the Andes in a region extending south from the southern edge of the Amazon basin.29 This is broadly the same region in which manioc was also domesticated,30 and in both cases we can only go on the dates of the earliest surviving materials—currently put at around 8000 years BP31—to guess when domestication in fact took place. Certainly it was before 8,000 years ago, but how long before is a matter largely of conjecture and some authorities are already seeking to push the horizon back to at least 9,000 and perhaps 10,000 years ago.32
Manioc, also known as cassava, is a starchy crop, a good staple providing almost twice as many calories as potatoes weight for weight.33 But it is also so low in protein content that, as one specialist warns, “in manioc-dominated diets, protein-deficiency can lead to malnutrition and also aggravate symptoms related to manioc cyanogenic toxicity.”34
We’ll return to that issue of toxicity in a moment but let’s note, meanwhile, that peanuts have a very high protein content that makes them a perfect nutritional “complement to starchy manioc-based diets.”35 Several authorities have noticed the pairing of the two in ancient cultures and British botanist Barbara Pickersgill speculates that the wide prehistoric distribution of peanut cultivation may have accompanied the spread and uptake of manioc.36
America Before Page 18
