subtropical

Pseudocydonia sinensis - Chinese quince

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I first encountered this spectacular quince species at the Burbank Experimental Earm in Sebastopol, California. Notable for its massive fruit, which is at first a light green then turning yellow as it ripens. Among the apples, Sorbus domestic, and a number of other surviving Burbank species this one seems to be growing strong and quite productive.

The tree is a deciduous, semi-evergreen tree in the Rosaceae family (Rose, Pear, Apple, Loquat). Native to Eastern Asia in China this is the sole species in the Pseudocydonia genus. Previously Pseudocydonia was placed in the Asian genus Chaenomeles, however differs in that Pseudocydonia lacks thorns and produces single flowers. The Chinese Quince is closely related to the European Quince, Cydonia bologna. The two species differ in that Chinese quince has somewhat serrated leaves and smooth fruited skin. The fruit on the Burbank Hybrids also appear to grow larger.

The tree is referred to as mùguā-hǎitáng (木瓜海棠).In Chinese, mùguā (木瓜) also means, “papaya”.

Grows 8-10 m long. The fruit is a large ovoid pome 12–17 cm long with five carpels; it gives off an intense, sweet smell and it ripens in late autumn.

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The large fruit is hard and astringent, however after a period of frost the fruit does become a bit softer and less astringent. The fruit can be used in the same way as quince, poached, baked or used for making jam. The tree is also grown as an ornamental in Southern Europe.

In Korea it is used to make a preserved quince and quince tea.

The bark and trunk of larger trees are highly ornamental. The wood is frequently used in Japan for shamisen, a three-stringed traditional Japanese musical instrument derived from the Chinese instrument sanxian.

The fruit is used extensively in Traditional Chinese Medicine to treat rheumatoid arthritis. Recent pharmacological studies suggest that extracts of phytochemical in the fruit have antioxidant and antiviral properties.

Nicotiana rustica - mapacho, махорка, thuốc lào, tobacco

BACKGROUND AND ORIGIN

This is an enthogenic species of Nicotiana (tobacco) native to South America containing up to nine times more nicotine then commercial Nicotiana tabaccum. N. rustica leaves also contain high levels of β-carbolines including harmala alkaloids.

USES AND ETHNOBOTANY

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In South American ethnobotanical preparations, Mapacho (Nicotiana rustica) leaves are soaked or infused in water, and the water is then insufflated into the stomach in a preparation known as singado or singa; the leaves can also smoked in cigars , used as an enema, made into a lickable product known as ambil, and made into a snuff with the bark of a species of Theobroma, creating nu-nu. In the southeast part of Turkey, people use this herb and ashes of some tree bodies to make a moist snuff called maraş otu. They use this by putting the mixture under their lips like Swedish snus or Afghan naswar. It is also a common admixture of Ayahuasca in some parts of the Amazon. The leaves of N. rustica can be used to make a powerful organic insecticide and are used in the production of pesticides due to the high concentration of nicotine. I keep the plant scattered here and there throughout the garden as I feel its presence deters some detrimental garden pests.

One word of advice would be to not self - administer this plant without full knowledge of its potency and potential effects.

PROPAGATION AND CULTIVATION

Nicotiana rustica can be easily propagated from seed. As the seeds are very small, the most straight forward method I have used is to lightly sprinkle seeds across a moist propagation medium. If seeds are kept in a humid environment they do not need to be covered in soil to germinate. Wait until seedlings have developed their seconds set of leaves to divide them and transplant into individual containers. 

Portulaca oleraceae - Purslane, verdolaga

BACKGROUND, ORIGIN, AND DISTRIBUTION

The plant is a prostrate fleshy herb with spreading branches. Leaves are fleshy, shiny and widest at the tips, shaped like a water droplet. Flowers are born terminally in clusters, with small round seed pods dispersing numerous small black seeds.

This is a common, spontaneously appearing plant found growing throughout the tropics and warmer temperate regions. The wide range is due to high genetic flexibility which permits rapid adaptation to new environments. There are many forms, with different size leaves.

PROPAGATION AND CULTIVATION

Cultivation of this plant is easy, and it is most familiar to most people as a spontaneous "weed". In favorable tropical climates it can be readily observed growing out of cracks in sidewalks, even out of rubble and deteriorating walls. Increasingly, due to its reputable health benefits and nutritious properties, improved purslane cultivars/varieties can be found, faster growing with larger leaves.

The plant is cultivated in France, Denmark and the Netherlands. 

As a companion plant, purslane provides ground cover to create a humid microclimate for nearby plants, stabilising ground moisture. Its deep roots bring up moisture and nutrients that those plants can use, and some, including corn, will follow purslane roots down through harder soil that they cannot penetrate on their own (ecological facilitation). It is known as a beneficial weed in places that do not already grow it as a crop in its own right.

USES AND ETHNOBOTANY

The leaves and shoots can be eaten raw and have a mild but pleasant taste. The leaves also make a good forage for poultry. The plant is versatile when it comes to how it can be eaten, and can be mixed into most any dish, raw or cooked.

In East Africa the seeds are ground into a flour that is used to make porridge.

Purslane contains more omega-3 fatty acids (alpha-linolenic acid in particular) than any other leafy vegetable plant. Studies have found that purslane has 0.01 mg/g of eicosapentaenoic acid (EPA). It also contains vitamins (mainly vitamin Avitamin Cvitamin E (alpha-tocopherol),[15] vitamin Bcarotenoids), and dietary minerals such as magnesiumcalciumpotassium, and iron.

 

 

 

 

Pachira glabra - Saba nut, Guinea peanut, French peanut

BACKGROUND, ORIGIN AND DISTRIBUTION

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Originating in Mexico, Guiana, and  northern Brazil, Pachira glabra is similar looking and closely related to Pachira aquatica, the Malabar chestnut. In Brazil the Saba nut is a fruit tree, cultivated as an ornamental in south-eastern areas of the country.  It is not very frequent in its natural habitat, the pluvial Atlantic forests from Pernambuco to Rio de Janeiro and the flood plain forests of Para and Maranhao. Today this species is distributed throughout the tropical world, used both as an ornamental tree and a food crop. 

It is a small evergreen tree 4-6 m tall. The fruits are semi-woody capsules which stay green even when ripe. Like many of the Bombacaceae species P. Glabra has a very fat trunk to store water. Just after germination the girth of the trunk becomes noticeable, almost disproportional to the rest of the tree.

USES AND ETHNOBOTANY

The tree produces a fruit/pod which contains many edible seeds which can be consumed raw or toasted/roasted/boiled. The seeds contain 16% protein and 40-50% fat. P. glabra along with P. aquitaca are both considered to be among the more notable under appreciated tropical food crops.

The young leaves and flowers of P. glabra (and P. aquatica) are also edible. 

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Mature trees will produce between 50 - 80 fruits per year.

PROPAGATION AND CULTIVATION

The tree can be propagated from seed, cuttings, and air layers. Trees are resilient to both droughts and flooding. 

USES IN REGENERATIVE AGRICULTURE

P. glabra makes a fantastic full sun / deep shade tolerant, medium size, understory seed/nut crop. Trees are resilient to pests, they drop a thick leaf biomass year round and produce abundant fruit. The trees are relatively maintenance free aside from irrigation upon initial establishment. 

Alternanthera sissoo - Sissoo spinach, samba lettuce

DESCRIPTION, ORIGIN AND DISTRIBUTION

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The plant is reportedly native to the region of Brazil in South America. Although it is referred to scientifically as Alternanthera sissoo hort., there are no known scientific descriptions of its taxonomy.

USES AND ETHNOBOTANY

The leaves are edible. Preferable the tender young tips are pinched off and eaten either raw or steamed. The leaves are pleasantly crunchy, more so then the temperate climate spinach. When consumed in large quantities it is suggested that they be steamed or boiled, due to the presence of oxalates in the leaf.

Sissoo spinach can be added to quiches, pies, curries, dals, pasta sauces, lasagna or added to dishes and stir-fries late in the cooking process as a spinach substitute and to add a nutty flavour.

PROPAGATION AND CULTIVATION

Stem tip cuttings with one or two nodes root easily planted directly in the field.

Sissoo seems to do best in the partial shade, ideally grown in patches guilding larger trees. Having experimented cultivating sissoo in full sun I found that they are remarkably resistant to drought. Although the hue and overall quality of the leaf is diminished in exposed, dry conditions, the plant still seems to grow quickly.

Sissoo is best harvested by picking off new tips, thus the plant can be maintained as a low thick groundcover.

When left unharvested, and in prolonged dry periods, sissoo will flower. To my knowledge I have not yet seen sissoo seed, since the plant can be grown so easily from cuttings I haven’t examined the flowers much.

 

Agroforestry species database from the World Agroforestry Center

The World Agroforestry Center recently announced and released a new multi-database search engine, or switchboard for information on Agroforestry species.

The 13 websites the Switchboard links to include The Plant Resources for Tropical AfricaThe Useful Tree Species for AfricaTree Seed Suppliers DirectoryThe UNEP-WCMC Species Database,  and The VECEA interactive vegetation map. In addition to directly harnessing information from these 13, the switchboard also provides hyperlinks to The Plant List,  Tropicos,  Royal Botanic Gardens, Kew, and The Global Biodiversity Information Facility.

The Switchboard’s main strength is that it shortens the time and energy spent on searches, and generates quality information drawn from trusted sources,” says Roeland Kindt, the senior ecologist at ICRAF who led the development of the tool. “Its creation was driven by a need expressed by users, for a “one-stop-shop” for good quality and detailed information on species of interest,” says Kindt.

Users can search for information in two ways:

– See more at: http://blog.worldagroforestry.org/index.php/2013/10/23/new-agroforestry-species-switchboard-means-easier-faster-access-to-quality-information/#sthash.o0d79nTR.dpuf

Complex Agroforestry and the Built-Environment

Note: This is a portion of an essay I wrote a number of years ago (in 2007) and is best read in conjunction with two additional articles I have posted on this site: Chinampa: Raised-Bed Hydrological Agriculture  and  The Domesticated Landscapes of Los Llanos de Moxos, Bolivia.

Complex Agroforestry and the Built Environment

By Spencer Woodard

2006 – 2007

Agroforestry is currently receiving considerable attention as a stable and ecologically viable form of tropical forest land use (Alcorn, 1984; Budowski, 1981; Hart; 1988; King & Chandler, 1978; Salas, 1979; Spureon, 1980; Weaver, 1979; Denevan, 1987). Traditional forest farming techniques provide us with one of the most logical and effective models of intelligent land management. Recent studies have demonstrated that some of the most successful food-producing adaptations to rainforest environments have been those of indigenous people (Erickson 2005; Heckenberger et al 2007; McNeely 2004; Miller & Nair 2006). These complex systems were developed and refined over thousands of years and, although now in peril of destruction and disappearance, they can still provide us with insight into how we can properly and sustainably manage our soils, water, crops, animals, pests and so forth (Thrupp 1998; Altieri 1999; McNeely 2004). In order to properly go about studying these historical systems we must understand their features through a variety of disciplines. Furthermore, we must begin to put information into practice that is extracted through experimentation and field research.

 

Historically conservationists have focused their attention on protecting ‘natural’ forests, these include landscapes which are understood as existing in a ‘pristine,’ ‘virgin,’ or ‘primary,’ state and deemed as such based on the idea that they have suffered from little or no direct human impact. However, there exists a rapidly accumulating body of evidence to support the view that very few of today’s forests, anywhere on earth, can be considered to truly exist in such a state (McNeely 2004). Not only do studies suggest that large portions of the neo-tropical forest landscapes of the Americas are anthropogenic, but that biodiversity in these anthropogenic areas is now equal to if not higher than areas which were not inhabited by large pre-Colombian societies (Erickson 2005; Atta-Krah et al. 2004; McNeely 2004).

Western society has fabricated a romantic, mythical vision of the untouched wilderness and the dominant conceptions of pre-Colombian native peoples that dwelled within these environments – small, idealized populations of semi-nomadic humans whose impact on the earth’s landscape was invisible or non existent. Despite the many misconceptions, there exists more than ample irrefutable evidence demonstrating how, up until the end of the fifteenth century, the Americas supported dense human populations which substantially altered the forest and topography in ways that proved beneficial to both human and non human life-forms (Heckenberger et al. 2003; McNeely 2004; Denevan 1967, 1992, 2001; Erickson 2005). McNeely argues that “the Western vision of an untouched wilderness has permeated global policies and politics in resource management. This view of forests is based on an outmoded ecological perspective, and on misunderstanding of the historical relationship between people and forests, and the role people have played in maintaining biodiversity in forested habitats.” It is important that modern peoples begin to understand that much of the older vegetation throughout the world is the legacy of past civilizations; managed agroforests that were abandoned hundreds of years ago during various waves an periods of colonial onslaught. Although this paper will focus on the tropics of the Americas, McNeely goes further, with examples from Asia, the western hemisphere, Europe and the Mediterranean, to demonstrate that cycles of human activity have affected biodiversity in forests worldwide (McNeely 2004: 157-160).

Perhaps one the most noteworthy reasons why early Europeans did not detect the presence of extensive, highly diversified land management and resource renewal techniques employed by native populations of the Americas was because indigenous systems were so masterfully executed; the artificiality of the built environments totally eluded the unobservant foreigners. One culture’s masterful creation was perceived merely as wild nature in dire need of “taming” to the newly arrived other. The first Spanish visitors would not have understood any other approach to land management and food production distinct from those employed in Europe at the time. So Mesoamerican Indians were seen and portrayed as hunter/gather primitives who had not yet “discovered” plant and animal domestication. In reality, as I will continue to stress throughout relevant discussion, in terms of logic, efficiency, renewability and productivity, pre–Colombian populations of the Americas practiced a refined and far superior agricultural technology which reached far beyond the faulty models that existed (and have persisted) throughout Europe at the time.

The indigenous approach operated at an altogether elevated degree of sophistication in terms of management and functionality, working towards both societal and ecological sustainability under the precept that you can’t have one without the other. Hundreds of species of edible, medicinal and other useful plants and animals existed within large tracts of built forest, all constructed, managed and harvested by local populations. In his recent book, 1491: new revelations of the Americas before Columbus, author Charles Mann recounts a conversation with anthropological botanist Charles Clement, from the Brazilian National Institute for Amazon Research. In one brief but impacting statement Clement says, “Visitors are always amazed that you can walk in the forest here and constantly pick fruit from trees, that’s because people planted them. They’re walking through old orchards” (Mann 2006, 343).

Planting, managing and harvesting their forest gardens over thousands of years the first Amazonians slowly transformed large swaths of natural forests into something more useful, something that would function as undomesticated nature had, as a stratified, self-sustained forest ecosystem, providing habitat for native flora and fauna, yet the customized forest would also provide a wealth of products necessary for human existence.

“Swidden-Fallow” agroforestry describes a traditional method of modifying and managing forest environments on a larger scale as is still widely practiced throughout the Amazonia. Balee (1994: 116-165) describes this practice of forest management as, “the manipulation of inorganic and organic components of the environment that involves direct and indirect human interferences in species populations distribution and behavior… some species may become locally extinct, but there may be an increase in the overall ecological and biological diversity.” It is worth pointing out that, due to lack of research, the highly productive method of swidden-fallow forest/food system management has seldom been commented on in the literature on shifting cultivation (Harris 1971: 482; Denevan 2001: 83).

The swidden-fallow process can be summarized as follows: A plot of forest is selected and surveyed, valuable, or desirable species occurring naturally in the area are identified and left in the area, all other undesirable species (of shrub, vine, tree, etc.) are removed. All biomass from felled vegetation is either left to slowly decompose providing nutrients and suppressing weeds, or it is burned for nutrients in the ash. Void spaces left by eliminated species are filled in with food, medicine, or other useful crops. Based on growth-rate, eventual size, and overall growth habits of the newly implemented plants and trees, plantations are made so as to mimic natural, stratified tropical forest design. Then the swidden site is left to fallow. In the time between a new planting and maturation of tree crops a swidden site can be intensively cultivated with annuals and perennials. Once young trees have developed a substantial canopy leaving the under-story with insufficient light to be cultivated with perennial crops, the site is left to mature and self-regulate while being harvested by humans on a regular basis. Thus an anthropogenic forest is created. If one is familiar with the concept of “slash and burn”, a more commonly discussed form of shifting cultivation, swidden-fallow might be understood as a similar approach, but with a greater degree of complexity and a heightened potential for longer-term, restorative agricultural.

“Fallow management involves both purposeful and unintended human manipulation of both individual plants and groups of plants, both wild and domesticated or semi-domesticated” (Denevan 2001: 84). In the first ten to twelve years a fallow is managed most actively and intensively where as older fallows require less management although they can be harvested for thirty-five years or more. It is common that old, unproductive fallow sites are remodeled and replanted to become young swidden once again, this way forests are replenished and selectively propagated, constantly maintained at their optimal productive capacity. Denevan (2001) reports that in contemporary intensive swidden systems the cropping to fallow ratio is high, one to three years of intensive cropping followed by twenty or more years of fallow. Denevan has concluded that high ratios of cropping (swidden) to fallow are probably not indicative of prehistoric methods rather, in other words, cycles of cropping and fallowing were more balanced out (Denevan, 2001: 68).  De Jong (1996) reports that farmers in the Peruvian lowland Amazon today do not continue the intensive use (cropping) of a fallow site for more than four years because of decreasing returns and increasing weed invasion make it less profitable than changing the field to a forest garden and make a new swidden elsewhere. Older fallows (forest gardens) require less human input than intensively cultivated swidden, but continue to be economically important (De Jong 1996).

One of the major reasons why the swidden-fallow method was developed by peoples living in various tropical regions around the world relates to the extremely poor condition of rainforest soils. Fallowing land after intensive cropping is one of the most basic and assured ways of restoring soil fertility; vegetation returns regenerating depleted nutrients.

Even today, out of all known domesticated plants in the Amazon, more than half are trees. (Depending on the definition of “domesticated” the figure could be as high as eighty percent). In the region inhabited by the Ka’apor, centuries of selective propagation through swidden-fallow cultivation and management have profoundly changed the forest community. Ka’apor-managed forests hold plant inventories of which almost half are used by humans for food, remaining species hold equally important value, as medicine, timber, etc. In similar forests that have not recently been managed, the figure is only 20 percent (Mann 2006: 343). Balee has estimated that at least 11.8 percent, about an eighth, of the nonflooded Amazon forest is “anthropogenic”, directly or indirectly created by humans. Many researchers today regard this figure as conservative, some will even go so far as to suggest that all neotropical forests were designed, constructed and managed over thousands of years by indigenous inhabitants. Clark Erickson maintains that  most, if not all neotripical landscapes are built environments and that the lowland tropical forests of South America are among the finest works of art on the planet (Mann: 343-344). Accordingly, Peter Stahl, an anthropologist at the State University of New York Binghamton, maintains that “lots” of researchers, including himself, believe that “what the eco-imagery would like to picture as a pristine, untouched “Urwelt” (primeval world) in fact has been managed by people for millennia” (Mann 2006: 344).

Today, indigenous forest management systems range greatly both in terms of scope and scale. There still exist groups of indigenous people, such as the Barasana Indians of the Colombian Amazon, who can identify every tree species (exceeding three hundred) in their territory without having to refer to the fruit or flowers. It is not uncommon that an Amazonian tribe will use more than 100 species for medicinal purposes alone (Plotkin, 2003: 147-155).  Among mestizo populations in more developed areas a family may own and manage one or a few fallowing fields which are intermittently renewed through selective removal and renewal of desired species. Smaller, more domesticate models may be found functioning as house gardens where they receive more intensive management. Home gardens are usually highly complex mixtures of perennials and annuals, medicinal, ornamental, fuel, and artisanal species. Fertility in home garden systems is maintained by decomposing plant matter, ash from cooking fires, biodegradable garbage and human and animal waste. Larger anthropogenic forests, such as those of the Barasana, among others, tend to be further removed, surrounding communal house sites. In some instances fallow sites are harvested which lie at a great distance from residences (Denevan 2001: 66-71).

Contemporary Amazonian homegardens of both small and large scale, serving domestic and urban populations, combine useful native species with fruit trees introduced from other parts of the globe during European colonization, as well as more recent introductions. Smith (1996) reports that, in more rural areas, homegardens appear to be designed and utilized more for domestic supply of fruits, condiments, medicines, craft materials and shade rather than to be sold to a larger consumer market. However, near more densely populated areas agroforestry systems often become part of both subsistence and income-earning initiatives, mostly through the production of marketable fruit. Overall the use of homegarden products is for domestic consumption indicating that, from the point of view of food security, homegardens can be a valuable option for small-scale farmers regardless of their distance to markets. Instead of cultivating one or two edible species, en masse, as is practiced by modern farming methods, tree-based homegardens integrate a wide variety of valuable products, more than would be required to sustain a comfortable existence (Miller and Nair, 2006).

The indigenous approach to land and resource management differs in a few fundamental ways from those existing and promoted by the western world. Briefly, I will highlight a few significant advantages to the indigenous technique: In terms of both plant and animal populations they were far more diverse, by hundreds, if not thousands of times. Organization and complexity, the basic foundation behind the design of diverse agroforestry systems, mimics the composition of “natural” forest landscapes. Built forests are constructed on multiple “dimensions”, or levels; potentially incorporated are vines, shrubs, groundcovers, shade loving and full sun plants, bush fruits, hardwoods, crown bearers, and so on. All propagated plant species are intermixed with one another as they would be found in a mature forest; together they function in one large multi-lateral symbioses, or alliance. Although the established complex agroforestry system does not depend upon the human being, the human can interact in harvest, maintenance and propagation; through selective propagation one obtains superior genetics enhancing growth-rates and productivity.

Whitmore and Turner emphasize the many different patchworks of agricultural microsystems within built landscapes, in which “each elevation zone was attuned to small-scale environmental variation, furthering the ability to cultivate a wider diversity of products.” Through the implementation and mastery of this type of food/resource production model indigenous societies did not fail, as Europeans already had (at the time of the conquest), in producing ample food for dense populations while simultaneously maintaining a diversity of biological organisms and local ecosystems.

 

McNeely (2004) draws some conclusions concerning dominant patterns in the history of forests and biodiversity, which can be summarized as follows: The most significant fact to consider is that human beings have always been a dominant force in the evolution of today’s forests. Historically technological development and forest degradation have existed in a corollary relationship with one another – as technology becomes more and more sophisticated forests undergo a greater degree of modification and/or destruction.  As overexploitation continues and resources dwindle, forest degradation becomes increasingly detrimental to human populations eventually leading to a forced cultural change which is manifested through a reduction of human pressure. Such changes in conditions will either result in regeneration of forests to highly productive and diverse systems, or it will result in permanently altered, less diverse and less productive landscapes. Historical and contemporary examples suggest that the best approach to conserving forests and their biodiversity is through a variety of management approaches ranging from strict protection to intensive use (McNeely 2004).

Based on the relationship between modern societies and forest ecosystems, the idea of “intensive use” conjures up images of abuse and eventual destruction; razing of forest and installation of industrial or commercial fixture. This is where we must begin to reevaluate alternative possibilities and methods of land use and management. Managing agroforestry systems to address biodiversity concerns will both enhance productivity and contribute to conservation objectives. Intensive use doesn’t necessarily have to imply abuse.

One of the major issues concerning contemporary methods of tropical forest utilization derives from the fact that modern forestry practices originated in Europe several hundred years ago and were developed for the purpose of managing temperate ecosystems with relatively few species on resilient mineral soils (Plotkin, 2003). Notwithstanding the many structural differences between temperate and tropical forests, European forestry methods have been encouraged in tropical regions of the world almost exclusively for the removal of timber. Timber extraction today requires the use of heavy machinery which causes great damage to fragile tropical soils, and, consequent to the great harm inflicted through the process of timber extraction, tropical forests have been utilized as nonrenewable resources, usually turned into crop or pasture land that serves only for a few years before it is totally depleted.

How can tropical forests be utilized for their many renewable resources in ways that will still generate some sort of economic return without causing disastrous outcomes? One relatively obvious solution would be to focus more attention on the many non-timber products occurring within tropical ecosystems, such as foods, medicines, oils, waxes, fibers, latexes, tannins, dyes, resins, natural pesticides, spices, and other non-wood products (Plotkin, 2003).

The most logical approach towards the realization of the potential value in non-timber products is through the science of ethnobotany, which includes the investigation and evaluation of the knowledge of all phases of plant life among primitive societies and of the effects of the vegetal environment upon the life, customs, beliefs, and histories of these peoples. Ethnobotany studies the “totality of the place of plants in a culture and the direct interaction by the people with the plants”, offering an effective approach to the conservation of tropical forests through the expansion of our comprehension of the value in tropical forests beyond mere hardwoods (Ford, 1987). With this expanded knowledge commodities might be extracted with minimal ecological damage while simultaneously providing incentive for the conservation and rational utilization of tropical forests (Plotkin, 2003).

The agroecological approach encompassed by the practice of complex agroforestry offers a practical method of managing forests and restoring agriculture lands that have been degraded through the abuse of modern agricultural systems. As history has proven, through proper design and management techniques, rainforests and other terrestrial environments can potentially sustain large, dense populations, intensive cultivation and environmental protection without suffering from depletion and eventual destruction. The adoption and reintegration of traditional methods into our modern infrastructure would introduce and encourage resource management practices that are not only productive and environmentally sound but could actually help to enhance and improve ecosystems and biodiversity.

— Spencer Woodard (2007)

Chinampa: Pre-Colombian raised-bed hydrological agriculture

Note: Following is a paper I wrote years ago (2006), when I first became interested in the history, evolution, and eventual Spanish-inflicted decline of Aztec Chinampa agriculture. The essay draws from much of the past and present research devoted to understanding these systems. It is the first part of a two part paper. The second part concerns the raised – bed / canal systems of Los Llanos de Moxo, Bolivia.

Please feel free to contact me with any questions / additional info at spencer (dot) woodard (at) gmail (dot) com

Chinampa: Raised-bed hydrological agriculture

By Spencer Woodard

“And when we saw all those cities and villages built in the water and other great towns on dry land, and that straight and level causeway leading to Tenochtitlan, we were amazed…Indeed, some of our soldiers asked if it was not all a dream” (Spanish chronicler, Bernal Diaz del Castillo)

“There is little doubt that the chinampas just south of Mexico City represent the most sophisticated version of Mesoamerican swamp agriculture. The complexes are extensive and most are strictly rectilinear, oriented roughly in accord with the sacred direction of Teotihuacan. The hydrology of the system has always had to be closely managed in order to prevent flooding, as well as to introduce sufficient fresh water to maintain levels and a slight flow in the canals. Production is year round and finely tuned. All in all, this is an engaging garden landscape or, rather, it was until mechanized commercial cultivation and suburbanization led to the obliteration of many chinampas” (Siemens 1980).

Adaptive systems involve careful planning, implementation and organization but offer the most logical approach to effective biodiversity conservation within food and resource producing systems. The raised-bed hydrological agricultural systems of antiquity offer an example of adaptive land management.

Chinampa describes a system, or network, of raised fields on low man-made islands in the middle of lakes, marshes and floodplains. Currently, the most intact, refined examples of chinampa agriculture can be found in the Xochimilco/Chaleco lake basins in the central valley of Mexico. Looking further, we find that similar land management techniques have been employed throughout the Americas. Another one of the more impressive and extensive examples can be found in Los Llanos de Moxos, in the Beni region of Bolivia. In the following pages, I will explore the importance of these sites as working examples of sustainable human living systems.

The examples of traditional raised-bed agricultural fields, such as those in Mexico and Bolivia, are widely regarded as the most productive and ecologically sustainable forms of agriculture in pre-Hispanic Mesoamerica (Chapin 1988).  “In a very real sense, chinampa agriculture has represented a self-contained and self-sustaining system that has operated for centuries as one of the most intensive and productive ever devised by man” (Chapin: 9).  It has been generally concluded that the level of technology reached in agriculture during this time was rarely equaled anywhere else in the world at the time. The use of human labor, hydraulic technological sophistication and administrative complexity were correspondingly high (Parsons, 1991; Torres-Lima et al. 1994).

In light of the current human-induced pandemic of global destruction, the theory and practice behind chinampa hydrological agricultural systems may become increasingly important for the conservation of agro-biodiversity and as a means for humans to adapt agricultural production to cope with volatile changes in global climates and weather patterns. The dwindling chinampero culture represents one of the few remaining groups of humans on earth who hold the knowledge and technique to build, cultivate, and maintain this highly restorative, productive and sustainable agriculture technology.

There exists a common misconception, that the Aztecs invented chinampa technology, in fact they did not. Although it has been widely recognized that societies of the late Aztec period developed the most sophisticated models, it is now clear that Chinampas were employed long before by lowland Maya. The chinampas of Chaleco and Xochimilco were inherited by the Aztecs through the expansion of the empire and domination of the regional indigenous population, the Xochimilicans. Indeed, archeological evidence suggests that throughout Mesoamerican prehistory raised-bed agricultural system use has been extensive and widespread, adapted to a diverse variety of climates and landscapes. (Leon-Portilla, 1992; Torres-Lima et al. 1994).

The Xochimilcas established themselves at the foot of the Cuauhtzin Hills of Mt. Ajusco on a peninsula that juts into Lake Xochimilo. All of their structures were made out of materials derived from the lake. As their numbers expanded the Xochimilcans began to create land on top of the lake basin wetlands by building up rectangles of vegetation (tulle reeds) layered with, organic matter and mud, excavated from the lake bottom. The resulting raised platform and water canal network functioned perfectly with gravity providing for adaptation to a wide range of weather patterns. Eventually thousands of artificial interconnected islands were constructed. It is thought that the city of Chaleco was originally settled by Chelmeca Indians, who practiced the same chinampa building techniques. The two cities resisted Aztec domination for over two hundred years. Finally, around the middle of the fifteenth century they submitted to Aztec rule. Despite the change in government, the two cities remained intact, expanding throughout the duration (Torres-Lima et al. 1994)

 

There is little doubt among experts that the human population residing within the valley of Mexico had easily topped one and a half million by the time of the Conquest. The Aztec capital of Tenochtitlan is thought to have supported a population of up to  three – hundred thousand people, which would have been around five times the size of King Henry’s London at the time. The immediate suburbs of Tenochtitlan are thought to have contained another 200,000 humans and, in addition, well over a million resided in the greater surrounding area including the greater 3,000 square mile central valley of Mexico. It is widely surmised that the majority of food stuffs consumed by this population came largely from the extensive, 1,200 square kilometer chinampa raised-bed and canals network built as inter-communal hydrological and agricultural infrastructure (Redclift 1987; Chapin 1988: 10; Outerbridge 1987; Garavaglia 1992: 572-573).

Descriptions of the Capital by the first Spanish conquistador/chroniclers baffle the mind for we can only barely comprehend such a human living environment:

It was bigger than Paris, Europe’s greatest metropolis. The Spanish gawped like yokels at the wide streets, ornately carved buildings and markets bright with goods from hundreds of miles away. Boats flitted like butterflies around the three grand causeways that linked Tenochitlan to the mainland. Long aqueducts conveyed water from the distant mountains across the lake and into the city. Even more astounding than the great temples and immense banners and colorful promenades were the botanical gardens – none existed in Europe (Mann 2006)

The first hand account of Francisco Lopez de Gomara (1553) describes the Aztec capital as a city…

…built on water, exactly like Venice. The whole body of the city is in water. The wide and pleasant streets are of three kinds. Some consist entirely of water with a great many bridges, others are completely solid, and a third type combines solid and water, with people walking on the dry half and using boats on the other half… Almost all houses have two doors: One leading to the pavement and the other to the water on which they travel by boat.

 

It has been estimated that 10,000 hectares of chinampa fields, under intensive cultivation, would have been sufficient to supply at least half a million people with basic food staples (Torres-Lima et al. 1994: 39). The Chalco/Xochimilco site is situated in an endorphaic lake basin at an altitude of over 2,240 meters and surrounded by a high mountain range whose highest peak reaches 5,452 meters. Within this region there is evidence that over twelve thousand hectares, or 120 km sq. of land, was reclaimed in the shallow areas of the lakebed and transformed into a chinampa network yielding around 9000 agriculturally viable hectares, all within an ingeniously irrigated and navigable hydrological aqua/agricultural system (Armillas 1971; Arco & Abrams; Torres-Lima et al. 1994).

Because the productivity of chinampa fields increased with the physical expansion of the system Tenochtitlan deliberately made the commitment to large-scale wetland reclamation so as to secure a subsistence base through this highly productive and accessible agricultural method, which had potential for expansion as long as there was space available (Arco & Abrams; Parsons 1991).

As a result of massive depopulation after the arrival of the Europeans, due to disease, slavery, massacre, missionization, resettlement and war, the vast majority of indigenous inhabitants who had previously played a central role in the structure, composition and day-to-day management of the landscape were eliminated. The Spanish are reported to have been single-handedly responsible for the destruction of these vast and impressive landscapes. In one especially destructive incident, stones were stolen from the massive Nezahuacoyotl dike so that the Spanish could erect their obscene and comparatively rudimentary and inferior colonial cities upon and around the ruins of Tenochtitlan, a site we know today as Mexico City. After the Spanish invasion and the destruction inflicted upon the chinampa systems at Tenochitlan, the spring fed lakes of Xochimilco and Chaleco were steadily depleted. By the end of the 17th century the Indigenous population of the valley of Mexico had plummeted from 1.5-2 million just before the conquest to 70,000 not much more than a hundred years later (Outerbridge 1987; Redclift 1987; Chapin 1988; Barra 1996).

The Tenango and Tlalmanalco rivers, which for millennia had supported the fresh water supply to Lake Chaleco, were diverted and springs were tapped, leaving the lake dry by 1900. Without the time tested and highly effective chinampa network in place, devastating floods would periodically haunt the city. Lacking the experience and adaptive capacity of the Aztecs who had logically and effectively controlled the water for thousands of years, the Spanish tried to get rid of it altogether, digging huge ditches and draining the vast lakes which would ultimately worsen the problem and lead to wind storms of noxious ground salts from the saline lake bottoms, which persists today as Mexico city’s worse natural scourge (Torres-Lima et al. Chapin 1988; 1994; Mann 2006).

The incessant expansion of contemporary Mexico City has not acted kindly upon the chinamperia. At the beginning of the nineteen hundreds the Porfista government decided upon what they thought would be a viable solution to the ever-present problem of insufficient supply of potable water supply. The city would pump water from Xochimilco’s large springs, which for centuries had generated water supply for the chinamperia. Nativas spring, the largest at Xochimilco, would be pumped at two cubic meters a second and the city’s ravenous thirst would be quenched. The project was executed within eight years in which time Mexico City had grown thus demanding more. Additional pumps had to be installed, increasingly bigger and more powerful, until all major springs to Xochimilco were tapped and the lake began to dry up. All of the smaller, peripheral chinampas suffered from the dwindling availability of water due to their slightly higher elevations, canals dried up making irrigation difficult, if not impossible, and the productivity of soil plummeted the surviving generation of chinamperos were forced to sell their property to housing developers and the like. When the outcry of displaced populations and destroyed agriculture technologies were heard by the Mexican government it was agreed that the pumping would be reduced by a little bit and that the city would grant Xochimilicans with the city’s semi-treated black-water sewage. Eventually the city began to suck straight from the groundwater surrounding and directly supplying the chinamperia causing it to sink, “like a dry sponge, the subsoil is compacting and the chinampas are sinking” (Outerbridge 1987: 80-82). By 1988 half of the chinampa’s remaining 2,300 hectares were actively farmed, the rest had been destroyed; consumed by the encroaching sprawl of the great metropolis. Today only two hundred hectares remain and not all of them are in production. What does remain is largely put to use for somewhat disheartening purposes: a place where tourists come to be polled about in the canals underneath the canopy of a brightly painted boat; a place where underpaid laborers are put to work toiling in the fields to grow ornamental flowers to satiate the whimsical desires of wealthy, ornamental flower-buying people; and, finally, as a place for the city to dump its trash and human waste (Outerbridge 1987: 82-83; Torres-Lima 1994).

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The word “chinampa” is thought to have been derived from the Nauhatl words chinamitl, meaning “reed basket,” and pan, meaning “upon.” The etymology aptly describes the basic idea of chinampa construction, which was traditionally executed by way of piling bed-clay and mud from the lakes, aquatic plants, dry-crop silage, manure and silted muck upon one another in precise layers between paralleled reed fences anchored in the lake bottom. The material used in constructing the raised platforms is excavated so as to create narrow canals which divide elevated areas. The result was a highly ornate, intricate and accessible system.

The historically sustainable components of the chinampa agriculture, as summarized from conclusions drawn by Torres-Lima et al. (1994), are as follows: 1) by conserving renewable resources and reducing environmental impacts, the farmers efficiently managed the lake habitat for agricultural purposes; 2) through recycling practices, they maintained nutrient flow and wastes cycles; 3) by conserving a high degree of biodiversity in time and space, they efficiently used the resource base, increased biological interdependence between crops and pests, and  reduced crop failure; 4) to intensify the production and increase sustainable levels of productivity, the farmers relied on regional resources, efficient use of labor, and high technological complexity; 5) by using social and economic factors in decision-making, diversification of crops and maximization of returns were part of the development of self-sufficiency and economic viability of the chinampa system (Torres-Lima et al. 1994: 39).

 

The southern lake chinampa system of Mexico used an enormous numbers of intricate drainage canals, or zanjas, as well as the chinampa fields and canals. The fields and drainage canals, when aligned and cross-sectioned, form small islands, typically long and narrow ranging in lengths between six and nine meters (Wilken et al. 1969: 223; Armillas 1971: 653; Arco & Abrams 2006). The general layout of fields and canals consisted of long fingers of solid ground, which alternated with navigable waterways, resulting in a tight, intricate configuration. The raised platforms were typically narrow and rectangular in shape. It has been reported that beds traditionally measured 2 to 4 m wide and 20 to 40 m long, surrounded on three or four sides by canals (Torres-Lima et al. 1994: 38-49). Armillas (1971) reports dimensions of 2.5-10 meters wide and up to 100 meters long. The raised portions were usually built by alternating layers of mud scraped from the lake or surrounding swamps and thick mats of decaying vegetation over shallow lake bottoms or in marshy zones. Platforms rose up to a height of 0.5-0.7 meters above the water level, the sides reinforced with posts interwoven with branches. Willow trees were traditionally planted along the edges providing anchor and structural support. The depth of the canals varied, ranging from one to one-and-a-third meters (Armillas 1971; Torres-Lima et al. 1994).

Prutzman (1988) delineates the essential steps in chinampa construction.  First, chinamperos use a long pole to find an adequate base for a chinampa and when possible uses a cimiento, the remains of an old chinampa, as the foundation for a new one.  Next, strong reeds are “stuck” in the bottom to mark the base dimensions.  Then mud is excavated from around the base and piled atop the reeds and cimiento.  Mats of water vegetation are then cut and transported to the new chinampa.  These dense vegetative mats, or cesped, were primarily made from water lily and tule reeds. A nutrient-rich compost heap is created by layering mats of vegetation to form a thick cap.  Mud from the bottom of the lake is mixed with soil from an old chinampa and placed on top reaching a height of about one foot above the water level.  A porous base, rich in organic matter, is created through which water easily flows and irrigates through capillary action  Lastly, the sides secured with woven reeds, and then willow trees, Salix bomplandiana, are (traditionally) planted around the edges.

 

An alternative view of chinampa construction is presented by Wilken (1985) who suggests that aquatic plants have no structural role in chinampas; rather, he believes that plots are constructed by “simply extending drainage canals out into swamps or shallow lakes or back into low-lying shores” and then piling the excavated material onto spaces between the canals.  While the dredged mud inevitably contains aquatic plants, Wilken maintains that these plants are not important structural component (Wilken 1985). It would seem to me that aquatic plants would be a very important in defining structure on multiple levels. As aquatic plants decompose and turn into earth they serve to maintain overall mass of the raised bed in addition to augmenting the nutritional structure, or content, of the soil. The soil fertility of the raised bed is continuously renewed by scooping up and applying sediments and mud from the bottom of the waterway onto the raised fields, water plants cultivated on the surface of the waterways are intermittently layered with dredged material.

 

Benefits of the chinampa system are significantly amplified when the fields are tree-lined. Once mature and fully leaved, the trees create a canopy which serves a variety of crucial functions. Trees anchor the beds, creating a boundary and infrastructure. As trees grow larger their fruit and foliage drop off onto the beds and in the water where they function as mulch, or into the water where they decompose and turn into nutrients, or they are eaten by aquaculture species such as prawns, fish, turtles, caiman, and so forth. Planting trees helps enable microclimates; trees both block the wind and hold air in and underneath the canopy which achieves a higher temperatures and humidity levels thus greatly reducing, if not eliminating, frost damage and crop failure that would other wise occur in exposed areas (Arco & Abrams 2006). “Creating channels of warmer air, the morphology of raised fields and associated canals can raise air temperatures as much as 6.3 degrees Celsius above that of dry fields.” (Crossley 1999: 280)  

Chinampas also regulate micro-climates by moving and retaining moisture through capillary action (between layers of soil and organic matter), the system promotes the cycle of nutrients between compartments. The result is living soil, with its own respiratory and circulatory functioning. Chinampas are also high in microbial organisms, both in the earth and water, which promote high yields of terrestrial and aquatic plants by continuous cropping and utilization of the diversity of niches.

Ingenious seed germination beds and seedling nurseries were employed in the chinampa system by the Aztecs, the Maya, and, most likely, Mayan predecessors. At the edge of the chinampa bed, at the water’s edge, low terraces are formed. These perpetually moist and humid environments, called “almacigas”, are filled and maintained with ultra-nutritious sludge scooped from the bottom of the chinampa canal with a customized long-handled pole basket called the “zoquimaitl”, seeds are germinated and cared for in these customized environments. “These seedbeds with their concomitant protective and growth promoting mechanisms are the real core of chinampa agriculture. Without them this type of cultivation could function no more effectively than any other kind” (Outerbridge 1987: 80).

Coe (1964) provides details of this practice: At one end of the chinampa near a canal the almaciga is made by spreading a thick layer of mud over a bed of waterweeds.  After several days, when the mud is hard enough, it is cut into little rectangular blocks called chapines.  The chinampero makes a hole in each chapine with a finger or a stick, drops in the seed or cutting and covers it with either human or livestock manure.  For protection against the occasional winter frosts the seedbed is covered with reeds or old newspapers, however the introduction of trees along the perimeters or within the beds is an effective method to create microclimate underneath the canopy, raising the temperature and humidity, thus avoiding frosts. During dry weather the sprouting plants are watered by hand.  Once the plant is ready to be transplanted a cube is cut around each small seedling which is then directly placed in its designated place, which has been preconditioned with canal mud and a thick mulch of water plants (Coe 1964).

The highly logical and strategic placement of the almaciga is superior to the conventional centralized nursery system for a few reasons: For one, as mentioned, it maintains its own moisture and humidity, even during drought it is in close proximity to a water source, reducing labor input in the wasteful, time-consuming task of irrigating a large nursery area; plants are propagated exactly where they will be transplanted, maintained and eventually harvested, this greatly cuts back on unnecessary and inefficient transportation and transplants required by a centralized nursery; in addition you are able to mass propagate without using pots, bags and plastic containers; an additional benefit is that plants are germinated in the same soil that they will be transplanted to, this results in heightened rates of growth and productivity, the plant will be better adapted to the soil type. Another point is that the nutrient content of the canal water used for irrigation is far more complete and consistent in composition than any human-fabricated organic or chemical fertilizer.

The chinampa system is not only highly productive in terms of the rate and amount of production per land area and per inputs, but also sustainable in the sense of continuous long-term, year-round productivity. Facing a variety of constraints such as hydrological and climactic factors in addition to increasing demand for food, Aztec chinamperos successfully reached an equilibrium between sustained yields and ecological and management factors (Redclift 1987; Torres-Lima et al. 1994). Interestingly, Berres (2000) reports on how chinampa canals were not simply smaller versions of the lake on which they were constructed, including similar numbers and distributions of species and habitats, chinampa canals have actually been found to be more productive with heightened levels of biodiversity due to the creation of a wide variety of micro-environments (Berres 2000).

Elaeagnus x ebbingei - Silverberry, Oleaster

BACKGROUND, ORIGIN AND DISTRIBUTION

Elaeagnus x ebbingei, commonly called oleaster or Ebbing's silverberry, is from temperate / subropical Areas of Asia. It is a cross between Elaeagnus macrophylla x Elaeagnus pungens. It is a large, bushy, rounded shrub that typically grows to 8-10' tall and as wide. Branchlets lack spines. Leaves are evergreen in warm winter climates, but semi-evergreen to deciduous near the northern edge of its growing range.

USES AND ETHNOBOTANY

Elaeagnus fruit

The seeds can be eaten raw or cooked and are a good source of protein and fats. The fruit is edible, somewhat astringent until fully ripe (almost falling off), then very good and produced in large quantities. Fruits ripen in the middle of winter when few other fruit are available. Fruit will grow to be 3 cm long by 1 cm wide when ripe.

The fruit of all Elaeagnus species are a rich source of vitamins and minerals, especially vitamins A, C and E, flavinoids and other bio-active compounds. The fruit is also a good source of fatty acids, which is unusual for fruit. 

Reportedly, current research indicates that consumption of the fruit greatly reduces the incidence of cancer in humans. Not only that but the compounds in the fruit are possibly capable of slowing or even reversing the growth of cancers that are already in the body.

Flowers are inconspicuous but emit a very agreeable aroma.

PROPAGATION, CULTIVATION AND USE IN SUSTAINABLE FOOD SYSTEMS

The plant is nitrogen fixing, meaning its roots have a symbiotic relationship with certain soil bacteria which form nodules on the roots of the plant and fix atmospheric nitrogen. Some of this nitrogen is used by the plant itself for its own growth, however some of the nitrogen is also available for plants growing nearby. Thus, planting E. ebbingei near other food crops can improve growth and increase productivity.

Due to the versatility of this plant, it has a wide range of uses for use in regenerative agriculture, permaculture, and agroforestry systems. It can grow in full sun or shade and can handle hot dry summers. 

Elaeagnus can have a vine-like growth habit, especially when growing in the understory of a larger tree. Prune back annually to keep the plant contained as a dense hedge or shrub, the plant can take heavy pruning and produces abundant biomass.

Elaeagnus is very wind tolerant and can be utilized as a superior windbreak. It is also highly salt tolerant. It can be heavily pruned as a hedge or let to grow freely, reaching 5 m in height.

I have planted this species in temperate Europe and the Mediterranean Basin, as well as in California, its a tough shrub with with many diverse uses. I believe Elaeagnus ebbingei has major potential for use in sustainable agriculture systems and deserves further investigation, selection and development of superior fruit / seed varieties.