Forests and Human Health Jan-16-2013

The need for integration of multipurpose trees in agroforestry systems: The case of growing Moringa stenopetala (Bak. f.) Cuf in Ethiopia

Getachew Addis (PhD)
Ethiopian Health and Nutrition Research Institute, P.O.Box 1242, Addis Ababa, Ethiopia

Rapid developments in science and technology in recent times have revolutionized the entire human civilization in its truest sense. When the rapidness of development and research is so impressive, it is fairly easy to forget the inescapable fact that we are damaging the earth at an unprecedented pace. Climate changes mainly caused by humans pose clear, catastrophic threats. Carbon dioxide and other gases like Methane, Nitrogen Dioxide and Chloro Flouro Carbon, which were vital for life in maintaining global temperature at a relative equilibrium, are now responsible for disturbing the balance and causing excessive global warming through their excessive emissions caused by anthropogenic factors. Some of the small choices each human can make can save the earth from rapid destruction by climate change. It is only through collective efforts that the rate of global warming can be reduced. On an individual level, we should adapt to these climatic changes and change our lifestyles in order to bring total carbon emissions under control. Among other measures, planting more trees is one of the ways and means of reducing the emission of the aforementioned gases into the atmosphere.

In Ethiopia, environmental degradation including deforestation and soil erosion has been widely observed. Concerted effort made by the government and the public at large has brought promising results in curtailing the scale of degradation in some parts of the country. However, these achievements are the tip of the iceberg in view of the environmental destruction that was going on for many years. Although the degree may have been reduced, climate change is expected to continue with varying degrees of intensity under the existing scenario of global climate change due to the lack of commitment to reduce gas emissions by most industrial countries, who are the major polluters of the atmosphere.

The sociocultural communities that dwell in areas of marginal agroclimatic conditions in Ethiopia have been relying on the consumption of indigenous plants to cope with the food scarcity, which has been frequently prevalent or constant in the lives of many generations. Indigenous communities have taught us that there is a need to broaden the food base mainly through the use of indigenous plants which can grow under extreme conditions. Therefore, it would be appropriate to learn the lesson that we should grow plants which are capable of sequestering carbon and providing multiple uses of non-timber sources to local communities.

Food diversification through the promotion of underutilized edible plants would be of enormous help to alleviate food scarcity and malnutrition in Ethiopia. Species which have a better nutritional composition, have edible parts with a high harvesting value, are accessible during seasons of food scarcity and acute shortage and are valuable in preventing soil erosion and promoting the agroforestry system have enormous ecological and economic benefit. Due to the ever mounting population and subsequent higher demand for arable land, it can be safely assumed that the cultivation of trees for the mere reason of carbon sequestration at the expense of using the land for crop production is an unacceptable measure for local communities. A plausible choice can be the cultivation of multipurpose trees. One option in the lowland and midland agroecologies can be the expansion of the multipurpose tree, Moringa stenopetala, locally known as Haleko or Shiferaw. The plant meets most of the above important criteria. It is indigenous or naturalized in marginal agroclimatic areas in Southern Ethiopia. It is a fast growing, drought resistant as well as disease and pest resistant plant which makes it potentially important in Ethiopia mainly in areas of low and midland agroecologies having low annual rainfall.

Moringa stenopetala is a strategic tree that is used as a vegetable throughout the year in the drought prone areas of South Ethiopia and as source of oil in the adjacent Kenyan and Somalian localities. Evidence shows that M. stenopetala is a rich source of macro and micronutrients, including minerals and vitamins A, B and C. Moringa stenopetala is traditionally used to treat health problems including malaria, diarrhea, the common cold, stomach ache, asthma, diabetics, hypertension, wounds and epilepsy in Ethiopia, leprosy and coughs in Kenya and to facilitate delivery in Somalia. Moringa stenopetala is also used as animal feed, an ornament, a windbreak and live fencing by local communities in South Ethiopia. Laboratory studies have shown that the plant exhibits antibacterial, antifungal, antitrypanosomal and antispasmodic properties. Furthermore, the seed is extensively used to purify muddy water. Moringa stenopetala can also be used as a substitute for expensive conventional coagulants such as aluminum and ferric salts as well as cationic surfactants (which may cause cancer and Alzheimer's disease) and against the sorption of toxic metals such as Cd2+, Pb2+, Zn2+, Cu2+ and Cr3. The oil from the seeds can also potentially be used as the main ingredient in soap manufacture as practiced elsewhere using oil extracted from its close relative, M. olifera. Although M. oleifera has been shown to reduce fluoride levels and can be used in potable water defluoridation at a low cost, it is not known if the poorly studied M. stenopetala can be similarly used. If found to be effective, millions of people and their livestock in Ethiopian and other rift valley areas that are highly affected by dental and skeletal fluorosis would be the primary beneficiaries.

The cabbage tree (Moringa stenopetala) around residential houses in Konso, Ethiopia

So far, growing M. stenopetala as a source of food and for other uses, and its management as a component of the agroforestry system in the stone terraced land of Konso is not similarly exploited in Ethiopia even by many of the adjacent communities. Little attention has been provided to transfer the indigenous technology to other communities in the south and elsewhere in Ethiopia. In view of the actual and potential benefits of M. stenopetala viz. ecological, nutritional, biomedical, generating monetary income to the rural poor and the sequestration of carbon, there is a need to initiate the growing and promotion of its non-timber products at a wider level. This should be practiced all over Ethiopia where the agroecology is convenient for its growth, supported by systematic and multidisciplinary research.

Doketu village (with more than 1200 households) and an agricultural field in Konso of South Ethiopia: UNESCO has recently included the “Konso Cultural Landscape of Ethiopia” in its list of World Heritage Sites.

Major references

1. Addis, G. 2009. Edible wild and semi-wild plants of Hamar and Xonso (South Ethiopia) with emphasis on their ethnobotany and nutritional composition of selected species. PhD Thesis, Addis Ababa University, pp.261.
2. Guinand, Y. & D. Lemessa. 2001. A practical field guide to wild-food plants in Ethiopia: general description, edible parts, preparation methods and palatability. UNDP-Emergency Unit for Ethiopia, Addis Ababa.

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