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Tropical forest ecologist Varun Swamy ’01 conducts ecological research in the Amazon using drones and social media.
ven in a forest full of behemoths, the Brazil nut tree (Bertholletia excelsa) stands out. A statuesque beauty with an almost perfectly cylindrical trunk that can exceed 10 feet in girth, its massive crown towers over the Amazon rainforest canopy, rising 200 feet above the forest floor.
Within that crown, which can surpass 80 feet in breadth, the Brazil nut tree patiently nurtures a truly exceptional fruit—a wooden cannonball that weighs up to five pounds and takes more than a calendar year to mature.
In a good year, the largest nut trees can produce over a thousand cannonballs, or “cocos,” as they are referred to locally. When they are ripe, their sheer weight brings them crashing to the forest floor. Only two species of extant animals can break open the nearly half-inch-thick woody armor to access the nutritious treasures inside. One is the agouti, a tailless native Amazonian rodent with a penchant for gnawing through the hardest of nutshells to make its living. The other is a bipedal mammal who has played a major role in shaping the abundance and distribution of the Brazil nut tree across a vast lowland Amazon rainforest landscape, stretching from southeastern Peru across a wide swatch of the Bolivian lowlands, all the way to the eastern frontiers of the Amazon basin in the Brazilian state of Pará. Those bipedal mammals: Human beings.
An increasing volume of evidence from ecological and anthropological research over the past decade suggests that Bertholettia seeds were sown and their seedlings tended to by native Amazonians from centuries past, which would make it humankind’s most gigantic crop plant. Therein lies my fascination with this extraordinary tree, as well as my efforts over the past few years to better understand its reproductive ecology. It is a compelling notion that one of the keys to the survival and perpetuation of the Amazon rainforest beyond the 21st century is rooted in the efforts invested by preindustrial native humans five centuries ago.
The concept of the Amazon rainforest as a “prehistoric garden,” whose floral composition and diversity has been extensively influenced by pre-Hispanic humans, remains highly controversial. However, this much is indisputable: In the present day, a 300,000-square-kilometer area (close to twice the size of New England) of the Amazon basin is densely populated with Brazil nut trees, forming the backbone of a sustainable, extraction-based economy that supports the livelihood of more than 250,000 inhabitants of the region. Regardless of the “naturalness” of their present-day density, the Brazil nut tree (“castaña” in Spanish), has supported a regional economy spanning across three countries for over a century.
In Peru’s Madre de Dios region alone, which generates about 10 percent of the overall Brazil nut harvest (Brazil contributes 20 percent and Bolivia about 70 percent), the total annual value of the resulting economic activity is estimated at $8 million; more than 30,000 people are involved in the collection, transport and shelling of the nut, which comprises more than two-thirds of their annual income.
Year after year, decade after decade, thousands of centuries-old trees across a vast landscape form the cornerstone of a genuinely sustainable economy. The castaña harvest creates as close to zero ecological impact as it can get—trees within an extractive reserve are accessed by narrow foot trails, cocos are split open on site with a skillfully wielded machete, and the shell-on nuts (seeds, to be botanically precise) are stuffed into large sacks, or “barricas,” weighing up to 150 pounds. These sacks are manually hauled to the nearest riverbank, where they are loaded into boats that transport them to processing plants in the region’s urban hub. At these plants, an army of castaña “peladores,” or nut peelers (mostly women), skillfully crack open nut after nut all day long using a simple mechanical press.
When viewed against the alternative land uses in the Peruvian Amazon, the contrast is stark. The entire castaña harvest does not require a single tree to be cut down, and it keeps intact the forest ecosystem’s intricate ecological functions and incredibly high biodiversity. Conventional agriculture, on the other hand, destroys all of that, replacing thousands of tree species with a single crop plant that rapidly depletes the soil. Cattle ranching is even worse, converting a highly efficient carbon sink into a landscape littered with hoofed, methane-belching machines. But the starkest contrast, and by far the most destructive alternate land use in the region, is gold mining. Over the past 30 years, the Madre de Dios region has lost more than a quarter of a million acres (a third of Rhode Island) to mostly illegal, unmonitored and unregulated gold-mining operations.
The word “lost” takes on a profound connotation here. When viewed from high-resolution overflight or satellite images (or from an airplane window on a commercial flight), vast swaths of recently mined rainforest look like they have been subjected to an intense cluster-bombing campaign. It is a hellish, apocalyptic landscape—Sahara-esque sand dunes pockmarked with pits of green-tinged stagnant water, the result of razing the rainforest and literally washing the underlying soil to extract flecks of gold dust. From a macro perspective, it is a lucrative activity, with hundreds of millions of dollars’ worth of Peruvian alluvial gold produced annually. However, the ecological and socioeconomic costs are steep; mercury poisoning, violent crime, extortion, prostitution and human trafficking are byproducts of this flagrant ecological genocide, or ecocide.
I believe that a regional economy centered on the harvest of castaña trees is an integral element of a long-term sustainable future of the corner of the Amazon rainforest where I have worked and lived over the past 15 years. The challenges are formidable, but the potential is enormous.
At present, almost 100 percent of castañas depart the Madre de Dios region of Peru as shelled nuts, without any further value addition. By the time they arrive at a shelf in a Whole Foods or Trader Joe’s store, they have passed through multiple intermediaries and have been marked up to as much as 10 times their wholesale price in Madre de Dios. Instituting a fair-trade type of certification similar to successful ongoing schemes for coffee and cacao would ensure that Amazon-based castaña collectors and processors receive a much larger portion of the overall profits. There is also great potential for derived products such as castaña oil, butter and milk, which could be directly positioned against similar products from another nut, the almond.
The contrast between the sustainability of the castaña and the almond could not be greater: Almond trees grow in a vast monoculture that requires shockingly large inputs of scarce irrigation water in California’s parched Central Valley. It works out to as much as nine gallons of water per almond. Furthermore, almond trees require a veritable army of migratory beekeepers tending to billions of bees to pollinate their flowers each year. Millions of the same bees are killed each year by the widespread spraying of toxic pesticides required to impede a plague of agricultural pests that thrive in a monoculture.
Castaña nuts, on the other hand, require just solar energy. Castaña trees “create” rain by returning groundwater “back” to the atmosphere (a process known as evapotranspiration), while capturing large volumes of carbon dioxide and sequestering it in their living biomass. And they do all of this surrounded by a dazzling diversity of tree species that together harbor an even more staggering variety of life-forms: mammals, reptiles, amphibians, birds, arthropods, fungi and epiphytic plants. Castaña nuts are loaded with health benefits, containing an optimal combination of healthful fats, protein and fiber. They are also an excellent source of selenium, whose antioxidant properties have been linked with thyroid health, lowering blood sugar and LDL cholesterol, and improving cognitive function.
THE FUTURE—IN A NUTSHELL
Over the past five years, I have been part of a collaborative effort that combines the innovative use of minidrones and online citizen science to remotely monitor and collect data that will improve our understanding of the biological rhythms and life cycles of Amazon rainforest trees, and will help manage and protect these invaluable rainforest ecosystems in the long term. We called this effort Community Aerobotany, which is supported by a visionary Peruvian ecotourism company, Rainforest Expeditions, and the pioneering online citizen-science platform Zooniverse.
The concept is simple: A minidrone is sent out on programmed flight paths over the rainforest canopy, stopping over focal castaña trees to capture high-resolution images of their crowns. These images are uploaded to the project’s site on Zooniverse, where a simple interface allows citizen scientists from anywhere in the world equipped with a smartphone, tablet or computer and an internet connection to view and interact with these images. Following simple instructions, they explore the images and register data that tells us how and what each focal tree is doing—does it look healthy, has it suffered damage, is it shedding old leaves, growing new leaves, flowering, fruiting, etc.
The images are of such high resolution that users can even count the number of cocos visible on tree crowns and record them with mouse clicks (or finger stabs on a touch screen). On the back end of these efforts, we receive rows of data that summarize the observations of each citizen-scientist volunteer, which are aggregated into a rapidly growing database. Over a sufficient period, without actually setting foot in the forest, we will develop a much better understanding of the life cycles and ecological rhythms of castaña trees.
We will use this data to predict the production of castaña trees across a region a few months ahead of the annual harvest, which will greatly benefit “castañeros” in planning the logistics and economics of the harvest. We are also interested in exploring the potential impacts of global warming and climate change on the health and reproductive ecology of these trees in the near and longer-term future. None of this was even conceivable 10 years ago, and here we are now, conducting ecological research in collaboration with thousands of citizens across the world, using a device that costs less than a laptop computer and can be purchased at your neighborhood Best Buy.
The future of the Amazon, I believe, is literally in a nutshell—part of it, at least. The sustainable extraction of castaña nuts is a textbook example of one of the basic tenets of financial asset management: Keep the principal intact, and live off the interest. We must use the perennial gifts of the rainforest, and learn from the labor of Amazonian natives past, to ensure that future generations continue to reap the benefits of this magnificent ecosystem.
Varun Swamy ’01 has spent the past 17 years conducting and collaborating on research that examines the ecology of Amazon rainforests, the role of plant-animal interactions in maintaining biodiversity, and the cascading impacts of human disturbances on the present and future of these ecosystems. He holds a research fellow position at the San Diego Zoo Institute for Conservation Research and resides in the urban Amazonian jungle of Puerto Maldonado, Peru, with his wife and dog. firstname.lastname@example.org