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Systematizing the local ecological knowledge of M’Nongs in Vietnam’s central highlands

Vo Hung, MSc. (hung

The term local ecological knowledge (LEK) refers to a harmonious combination of highly valuable, long-standing knowledge and experience of ethnic communities accumulated through generations. It usually a combination of a community’s indigenous knowledge and that of other areas. It is, however, generally unwritten.

LEK plays an important role in developing farming systems and community-based management of forest resources. Technicians with a systematic knowledge of LEK can use it to assist communities in their production and management of resources.

A case study was done on the LEK of M’Nong communities in the Dak Lak province of Vietnam’s remote central highlands. The study focused on shifting cultivation and fallow land management.

The research site

The research area comprised tropical evergreen rainforests. It was chosen for its many sub-ecological zones, inhabited by different ethnic communities, resulting in diverse LEK.

The study looked at 73 households - 71 M’Nong and 2 Kinh families. The total population is 365, with 121 being under the labor age. The families mainly practice slash-and-burn agriculture, tend homegardens and grow paddy rice. Many of the people in the area suffer from poverty and depend on the benefits from natural forests.

Shifting cultivated land.

Researcher (right) interviewing a shifting cultivator.

Methodology and knowledge analysis

The study identified the LEK of the communities through a participatory research method, using various research tools (including interviews and a simple matrix) to discover existing local knowledge, 5 Whys, problem tree and SWOT. The LEK of the region was systemized using the Agroecological Knowledge Toolkit software (AKT 5.0), developed by the University of Wales, Bangor.

On the basis of this information, a diagram representing the different factors/components of the LEK was produced, based on the analysis of the causes and their relations. The diagram serves as a basis for current and future solutions and the development of the knowledge database to identify research needs for improving shifting cultivation and fallow land management.

The systematized information/knowledge groups

Fallow period after shifting cultivation

A fallow period of four to five years is generally sufficient to restore soil fertility. Increasing the number of years reduces wild grass, increases fertility, decreases soil erosion, increases the benefits from non-timber forest products (NTFPs) and decreases the occurance of pests and diseases. Negative aspects of a long fallow period include a reduction of the amount of land available for farmers to cultivate, an increase in the distance between homes and cultivated areas and a decrease in labor efficiency.

Length of cultivation

A fallow period of two to three years is the most suitable for basalt soil. If it is near a stream, a longer period is recommended. Unfortunately, the local farmers usually have limited resources, so they cultivate their farms longer than four years. As a result, yields are reduced; there is loss of soil fertility; soil erosion increases; pests and diseases cause more damage; and more labor is required for weeding.

Experiences in shifting cultivation

Some indicators for evaluating shifting-cultivated land


The experience of the M’Nong illustrates that local commumities can have significant traditional experiences and knowledge in managing and using forest resources. This experience tends to be unwritten and informal but is still valuable.

The components of LEK in the management of forest resources are closely connected and can be systemized and presented in a diagram of causes and effects. However, further research is necessary to identify LEK in different cultural and ecological localities.

Results of the research have contributed to the collection and analysis of valuable ecological knowledge in Vietnam’s central highlands. This case study has also identified new research needs on the techniques and organization of community-based forest management.

The author can be contacted at the Faculty of Agriculture and Forestry, Taynguyen University, Dak Lak Pro, Vietnam.

Medicinal and aromatic plants in agroforestry

Meka R. Rao (, M.C. Palada and Brian N. Becker

Medicinal and aromatic plants (MAPs) play an important role in the healthcare of people around the world, especially in developing countries. Until the advent of modern medicine, man depended on plants for treating human and livestock diseases. Human societies throughout the world have accumulated a vast body of indigenous knowledge, over the centuries, on the medicinal uses of plants.

About 12.5 percent of the 422 000 plant species documented worldwide are reported to have medicinal value. About 25 percent of the drugs in modern pharmacopoeia are derived from plants. Many others are synthetic analogues built on isolated prototype compounds. Up to 60 percent of the drugs prescribed in Eastern Europe consist of unmodified or slightly altered higher plant products. For example, the wild yam, Dioscorea villosa carries important therapeutic properties, including contraceptives, steroids and muscle relaxants for anesthesia and abdominal surgery. Some plants have quinine and artemisinin to combat malaria; digitalis derivatives for heart failure; and the anti-cancer vinblastin, etoposide and taxol. These compounds cannot be synthesized cost effectively, which means that their production requires reliable supplies of plant material.

The global importance of MAP materials is evident from the large volume of trade at national and international levels. During the 1990s, the reported annual international imports of MAPs for pharmaceutical use amounted to an average of 350 000 tonnes, valued at over US$1 billion. A few countries dominate the international trade. Japan and Korea are the main consumers of medicinal plants. China and India are the world’s leading producing nations. Hong Kong, the United States and Germany stand out as important trade centers. It is estimated that the total number of MAPs in international trade is around 2 500 species worldwide.

Medicinal trees in traditional agroforestry systems

Many plants in traditional agricultural systems in the tropics have medicinal values. These plants can be found in homegardens, as scattered trees in agricultural lands and on field bunds.

Despite the many medicinal values of these plants, they are seldom grown commercially. In fact, many of these species are more valued for poles, fuel wood, fodder, fruit, shade, and/or boundary demarcation; their medicinal value is considered secondary.

Forests and forest plantations

MAPs growing in forests often require or tolerate partial shade, moist soils (high in organic matter), high relative humidity and mild temperatures. The cultivation of MAPs can be undertaken in thinned forests and cleared forest patches, or as intercrops in new forest plantations.

In China, the cultivation of medicinal plants is an age-old practice under the name of "silvo-medicinal" systems. In northeast China, ginseng (Panax ginseng) and other medicinal plants are grown under pine (Pinus spp.) and spruce (Picea spp.) forests. In central China, many medicinal plants are planted with Paulownia tomentosa. In southern China, medicinal herbs are often planted under Bambusa spp. (bamboo) and Cunninghamia lanceolata (Chinese fir) forests.

A farmers’ cooperative in the northern lowlands of Costa Rica has successfully demonstrated the cultivation of the medicinal herb Cephaelis ipecacuanha in natural forests. It is exporting it to the Netherlands and Germany. Cultivating ginseng and several other medicinal plants in forests is increasingly becoming a popular form of agroforestry in North America. Light-demanding understory species (e.g. Echinacea spp.) may be initially intercropped to provide early returns from plantations. After canopy closure, shade-tolerant species such as ginseng and goldenseal can be intercropped.

Fungal diseases are a major concern in forest farming. The application of fungicide can be detrimental to the forests’ health. Therefore, proper spacing and mixed cropping are recommended. Mechanical cultivation may not be feasible under forested conditions, so labor availability can be a constraining factor.

Newly established forest plantations can be intercropped with MAPs similar to food crops until canopy closure. The participation of the local people with the right to share in the benefits of the plantations, especially crop ownership, has assisted many Asian governments to establish and protect large-scale tree plantations, without conflict with the local people. This same participatory approach can be employed in the cultivation of MAPs in new plantations.


Homegardens are complex agroforestry systems involving many plant species, characterized by different morphology, stature, biological function and utility. They are mostly practiced in the humid and subhumid tropics. Homegardens of individual holdings generally cover small parcels of land and are established around homesteads. In the past, these systems were mostly used to meet the household needs of small-scale farmers in the forest margins. Although in recent times, increased urbanization, transport and market opportunities, have helped stimulate the production of cash-crops from homegardens. Food, fruit and timber species often dominate homegardens and occupy the middle and upper strata, while medicinal plants, spices and vegetables occupy the lower strata. Three medicinal plant categories are recognized in homegardens: species used exclusively for medicine; horticultural or timber species with complementary medicinal value; and weedy medicinal species. While the first two categories are deliberately planted, the latter group grows spontaneously. The species composition, plant density and level of management vary considerably depending on the soil, climate, market opportunities and cultural background of the people.

Riparian buffer zones

An agroforestry system that has received considerable attention in North America is the riparian buffer zone. This system can improve water quality, protect streams and rivers from degradation by nutrient loading and chemical pollutants from agriculture and urban areas and reduce erosion by attenuating peak flows. It also provides habitat for wildlife. Slippery elm (Ulmus rubra), harvested for its aromatic and medicinal inner bark, is commonly found in riparian areas in North America. Riparian buffer zones are an ideal location for this species, which suffers from commercial over-exploitation and the Dutch elm disease.

Intercropping MAPS

Two types of intercropping systems can be distinguished involving MAPs: medicinal plants as upperstory trees and MAPs as intercrops between other tree crops.

Medicinal plants as upperstory trees.

Coffee (Coffea arabica), cacao (Theobroma cacao) and tea (Camellia sinensis) are traditionally grown under the shade of multipurpose trees that produce timber, fruit, flowers and nuts. Medicinal tree species that grow tall and develop open crowns can also be used for this purpose. Examples include Parkia roxburghii, whose protein-rich seeds are used to treat stomach disorders, and Ginkgo biloba, whose nuts are used in Chinese medicine and are of high value. In the Ivory Coast, 19 of the 41 tree species planted as shade trees in coffee and cacao provide pharmaceutical products for traditional medicine. New plantations of coffee, tea and cacao offer scope for cultivation of forest medicinal trees that are in demand.

However, research needs to identify the medicinal trees that can be grown in association with these plantation crops and develop management practices for them. Tall and perennial medicinal trees that need wider spacing can be intercropped with annual crops in the early years until the tree canopy closes. Some of the medicinal trees may allow intercropping for many years or on a permanent basis, depending on the spacing and nature of the trees. The intercrops generate income for farmers when the main trees have not started production.

Medicinal plants as intercrops. Many tropical MAPs have the potential of being being intercropped with timber and fuel wood plantations, fruit trees and plantation crops. Some well-known medicinal plants that have been successfully intercropped with fuel wood trees in India include turmeric and ginger. Studies have shown that many medicinal plants can be grown in agroforestry systems. The trees may benefit from the inputs and management given to the intercrops. Short-stature and short-cycle MAPs and culinary herbs are particularly suited for short-term intercropping during the juvenile phase of the trees. The number of years MAPs can be intercropped with a given tree species depends on the size and intensity of its canopy shade, tree spacing and management, especially pruning of branches and the nature of the MAPs. Shade-tolerant and rhizomatic MAPs can be grown on a long-term basis in widely spaced plantations.

Intercropping medicinal plants in coconut stands is an age-old practice in India and other parts of South and Southeast Asia. These palms allow 30 - 50 percent incident light underneath, which is ideal for some MAPs like cardamon. Another plantation crop intercropped with MAPs is rubber (Hevea brasiliensis).

In the Caribbean islands, there has been increased interest in alternative crops like MAPs that have better economic potential than traditional crops.


Traditional systems of medicine in many developing countries primarily depend on the use of plant products either directly or indirectly. Besides serving the healthcare needs of a large number of people, medicinal plants are the exclusive source of some drugs, even for modern medical treatment. The use of plant products as nutrition supplements and in the cosmetic and perfume industry has increased the value of medicinal and aromatic plants in recent years. However, the overdependence on forests, natural woodlands and long-term fallows for the extraction of MAPs is threatening the survival of many valuable plant species. It is therefore imperative that such endangered species be cultivated outside their natural habitats to ensure a regular supply for human needs, as well as to preserve genetic diversity.

Cultivation is an important strategy for the conservation and sustainable maintenance of natural stocks. Moreover, growers must be strengthened in terms of their basic knowledge on the MAPs’ biology, ecology, propagation methods and cultural practices.

Reprinted, condensed and edited with permission from the publishers of The Overstory as cited: M.R. Rao, M.C. Palada and B.N. Becker. 2004. Medicinal and aromatic plants in agroforestry (The Overstory #135, published 1 March 2004). Permanent Agriculture Resources, Holualoa, Hawaii. Web:

Original source: Rao, M.R., M.C. Palada and B.N. Becker. 2004 [in publication]. "Medicinal and aromatic plants in agroforestry systems." In: P.K.R. Nair, M.R. Rao and L.E. Buck (eds). New vistas in agroforestry: a compendium for the 1st World Congress of Agroforestry 2004. © Kluwer Academic Publishers, Dordrecht, the Netherlands.

The authors can be contacted through Craig Elevitch, Director, Agroforestry Net, Inc., PO Box 428, Holualoa, HI 96725 USA, E-mail

A promising component in Philippine agroforestry: a land snail called bayuku (Ryssota ovum)

Jimson S. Solatre (

Agroforestry upholds the goals of rural development. It provides the needs of small farmers, and in some areas it contributes to the rehabilitation of degraded lands and the conservation of natural resources. This premise fuels agroforestry research and rural development initiatives to find the means to increase agroforestry production by engaging in diversified enterprises as integral parts of the system. Efforts are geared to pursuing non-traditional commodities, enterprises, production systems, and wild species of plants and animals that can be grown, produced, domesticated or reared that are compatible with the different agroforestry systems.

One interesting species that has the potential to be integrated into agroforestry systems is the land snail bayuku or Ryssota ovum (Valenciennes 1854). Bayuku belongs to the Family Helixarionidae and is synonymous with Ryssota otaheitana (Ferrusac 1821). It is endemic to the Philippines and is one of the 1 163 species of land snails thriving throughout the country. According to Springsteen and Leobrera (1986), its distribution is restricted to Luzon, although Faustino (1930) included the island of Panay in the Visayas among its range. Specimens collected by the Conchology Section of the National Museum of the Philippines show that this species has previously been collected in various parts of Luzon and the Visayas, particularly in the provinces of Quezon, Laguna, Oriental Mindoro, Albay, Camarines Sur, Sorsogon, Romblon and Samar.

Bayuku is a delicacy in areas where it occurs. Although its meat is in high demand, there has been no effort to domesticate or mass-produce it in the Philippines. Unfortunately, very limited documentation is available about the characteristics of bayuku. In order to assess its potential integration into agroforestry systems, a short survey was conducted in the Mt. Makiling Forest Reserve in Laguna, to describe its behavior, feeding habits and other attributes.

Behavior and feeding habits

In natural forests, bayuku is normally found at the base or buttresses of trees, the underside of forest leaves, underneath fallen branches, decomposing logs and rock depressions or weathered rock surfaces. The snail is difficult to see on the ground, as its brown shell is well-camouflaged among the dead leaves, rotten branches and the soil.

Bayuku (Ryssota ovum) meat is a favorite delicacy in areas where it naturally exists. Although its meat is highly in demand, there has been no effort to domesticate or mass-produce the snail in the Philippines.

The bayuku is nocturnal. As darkness approaches, it can be observed crawling, feeding or resting. At daybreak, it hides in sheltered places, concealing itself among the forest litter.

Bayuku depends on the availability of moisture for survival. It is abundant during the rainy season, its body is heftier and sturdier during this time. During the dry months, it is commonly found in damp areas or in cool places that prevent dehydration. Bayuku helps in the nutrient cycling of the ecosystem as it feeds on moist, decomposing forest debris and casts nutrient-rich fecal matter.

In the Mt. Makiling Forest Reserve, the study found that the natural enemies of bayuku were ants and birds. The most notorious was the black ant, Aphaenogaster treatae (Smith), while the most common predator was the Red Crested Malkoha, Phaenicophaeus superciliosu. The Malkoha feeds on the young bayuku by hurling it on stones and other hard objects until the shell shatters.

The bayuku’s survival is threatened by forest fires and over-collection. During fires, bayuku are burned because of their inability to quickly move out of the path of the fire.

Other attributes

Bayuku is considered a prize commodity in areas where it occurs naturally. It costs PhP5 - 10 (US$0.10) a piece. It is the most sought-after snail species, as its meat tastes like chicken gizzard. Aproximate analysis of the composition of the meat showed that it has a high protein content (Table 1).

Some people claim that the bayuku meat is an aphrodisiac, it is also said to help cure asthma. It can be used as a feed supplement for chicken and pigs. The empty shells can be used as drinking vessels, salt containers, ashtrays or can be pounded into lime, as mix for betel nut.

Potential of bayuku farming in agroforestry

Snail farming or heliciculture is a lucrative enterprise abroad because of the growing demand for snail meat. It has caught the interest of many entrepreneurs worldwide.

In France, the Bourgogne snail (Helix pomata) is served as "Escargot de Bourgogne" in first-class restaurants (Quiñones 1994). In the United States, imports of snail in 1995 comprised US$4.5-million worth of fresh, chilled, frozen, prepared or processed snails (The Alternative Farming Systems Information Center 2001).

The integration of bayuku farming in agroforestry offers some interesting prospects. This component could add diversity to the system and complement other production components that have successfully been integrated in the agroforestry system, especially in a multistorey system. The mixture of woody perennials would provide leaf litter and other biomass as food for the snail, while helping to enhance nutrient cycling in the system. The mature snails can be used as food and a source of additional income for farmers. Likewise, parallel efforts could be initiated to develop culinary techniques for the bayuku meat to transform this enterprise into a profitable business.

Bayuku farming does not require a large amount of starting capital. If it prospers, it will propel efforts in exploring non-traditional products that can be integrated into agroforestry.

Comparison of food composition per 100 g edible portion of bayuku (dry weight basis) with other food sources.

Food Sources








7 5.59




Pork (suckling belly)

6 9.20

1 8.30

1 1.20



Chicken (white meat)

7 5.3

2 0.6




Beef (lean meat)

7 0.60

2 3.10





7 1.00

2 1.70





6 6.80

2 3.40

1 0.40



(Source: Solatre 2003)

Bayuku (Ryssota ovum) is normally found at the buttresses of trees, the undersides of forest leaves, underneath fallen branches, decomposing logs and other forest litter, and weathered rock surfaces.

The author can be contacted at the National Economic and Development Authority, NRO-4B, NEDA Complex, Edsa, Quezon City, Philippines.


(1) ERDB. Undated. Bayuku: A Delicacy and An Ally in a Forest Landscape. Unpublished. (2) Llamas, J. 2003. pers. Comm. Laborer, Learning Laboratory for Agroforestry - Institute of Agroforestry, CFNR-UPLB, College, Laguna. (3) Quiñones, NC 1990. Known Enemies, Unknown Friends. Canopy International. Vol. 16 (6): p 3+.

(4) Quiñones, NC 1994. Some Facts and Updates on Edible Snails and Snail Farming. Tigerpaper. Vol. 21(1): p. 8-14..

(5) Springsteen FJ and FM Leobrera. 1986. Shells of the Philippines. Carfel Seashell Museum. Manila, Philippines.

(6) Solatre, JS 2003. Characterization of the Habitat and Food Preference of Bayuku (Ryssota Ovum Val.) in Mt. Makiling Forest Reserve. Unpublished Special Problem. UP Open University.

(7) Tadiosa, E. 2003. pers. comm.. Researcher, Botany Section. National Museum of the Philippines, Manila.

(8) The Alternative Farming Systems Information Center. 2001. Raising Snails, SRB 96-05. Retrieved from

Farmers try out agrihorticulture in semi-arid subtropics of India

A.S. Gill (

Agriculture in the semi-arid subtropics of India is difficult due to the area’s harsh agroclimatic conditions. The average rainfall is 900 mm, while evapo-transpiration is 1 800 mm. In general, the soils are shallow, have a low fertility and water-holding capacity. The per capita availability of the land is declining (it is currently 0.48 ha) and is projected to decrease to 0.15 ha. Under these conditions, farming can barely support one family. Agroforestry can supplement farmers’ production.

Applying agroforestry techniques, a farmer can produce food, fruit, fodder, fuel and fiber from the same piece of land. Despite the poor biophysical conditions of the area, fruit trees occur naturally along farm boundaries and thus provide a good source of income to the farming families. Successful on-station trials and field demonstrations have encouraged farmers to experiment with agrihorticulture on their farms.

On-farm trials were conducted in three villages of the Jhansi district, Uttar Pradesh. The Karari village used three kinds of fruit trees; the Simarda village, four kinds of fruit trees; and the Bhathagoan village, three citrus species. The fruit trees were planted using 6 x 6 m spacing and the interspaces were used to plant wheat during their initial growth years.

Table 1. Productivity of wheat in the interspaces of fruit trees in three villages of the Jhansi district, Uttar Pradesh, India.


Fruit tree species

Grain yield of wheat 9 (q/ha) from the interspaces of fruit trees

Common name

Botanical name

Karari village
(mean of 5 years)

Simarda village
(mean of 2 years)

Bhathagon village
(mean of 3 years)



Psidium guajava






Ziziphus mauritiana






Punica granatum






Citrus aurentifolia






Citrus sinensis






Citrus reticulata




As shown in Table 1, wheat yielded 36.10 quintal per hectare (q/ha, 1q = 100 Kg) when intercropped with Nimbu (Citrus aurentifolia) in the Karari village (with a mean of five years). The same goes for wheat, which yielded 34.80 q/ha (with a mean of two years), in the Simarda village. In Bhathagaon village, wheat yielded 32.89 q/ha (with a mean of three years) when intercropped with Mausambi (Citrus sinensis).

On the basis of these results, farmers in the three villages became interested in utilizing the interspaces of fruit trees, during their initial growth years, for producing wheat.

The author can be contacted at the Indian Grassland and Fodder Research Institute (IGFRI), Jhansi-Gwalior Road, Jhansi (UP) 284 003 India.

On-farm trial in the Karari village, Jhansi district, Uttar Pradesh, India.

On-farm trial in the Simarda village, Jhansi district, Uttar Pradesh, India.

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