February 22, 2012

Domesticating Indigenous African Tree Crops

Ebenezar Asaah, World Agroforestry Centre Zac Tchoundjeu, World Agroforestry Centre

Tree crops play an important role in securing the incomes and food security of rural communities in West and Central Africa. The work of the World Agroforestry Centre on “participatory tree domestication” is striving to employ techniques to strengthen and augment the contribution of such plants. Put simply, participatory tree domestication refers to the means by which rural communities select, propagate and manage trees according to their own needs, in partnership with scientists, civic authorities and commercial companies. It is usually oriented towards specific local markets and encompasses the use of both indigenous knowledge and genetic selection based on scientific principles.

Work to domesticate indigenous species started in Cameroon in 1997 to improve the yield and quality of the products, with a focus on species identified as the farmers’ priorities:  bush mango (Irvingia gabonensis), Safou (Dacryodes edulis), Njansang (Ricinodendron heudelotii), bitter kola (Garcinia kola), kola nuts (Cola species), yohimbe (Pausinystalia johimbe), prunus (Prunus africana). Through this participatory tree domestication process, methodologies for the selection of the trees with superior fruit and nuts traits have been developed and applied, and improved vegetative propagation techniques have reduced maturation periods while maintaining the desired fruit and nut qualities.

For example, Tchoundjeu et al. (2010) reported the multiplication of the bush mango by marcotting techniques with such trees fruiting in less than five years, whereas the same species take 10-15 years to fruit in the natural stands. Vegetative propagation techniques (stem cuttings, in vitro, marcotting and grafting) have also been developed and reported for safou.

Sign post of a typical farming group nursery producing improve planting materials.

Cultivation of these indigenous fruit trees has often been constrained by lack of improved planting materials. However, using tree domestication techniques, superior trees are selected and multiplied through vegetative propagation techniques. This then increases the availability and accessibility to improved tree planting materials of a diversity of indigenous fruit trees that will produce quality nutritious fruits and nuts rich in lipids and vitamins in less than five years.

With the aim of developing an appropriate mechanism for the transfer of tree domestication techniques to users, the Research Team in Cameroon opted to work directly with local communities and to promote the use of local knowledge in the selection of indigenous fruit trees with superior fruit and nut characteristics. Through this approach local communities were empowered on participatory tree domestication techniques in order to promote food self-sufficiency and/or enhanced nutritional benefits, generate income and employment. There is now growing evidence that in this way, agroforestry in general, and the domestication of indigenous fruit trees in particular, can help rural communities to be self-sufficient and to support their families on an area of less than 5 ha.

As a consequence, the domestication of indigenous fruit and nut trees is now becoming recognized as an important component of agroforestry which has meaningful impacts on the alleviation of poverty, malnutrition and hunger. For example, between 2008 and 2010, over 312 (253 men and 82 women) trainers of tree domestication in the western humid highland savanna zone of Cameroon were re-skilled on recent research results and technologies of participatory tree domestication. In turn, more than 5,000 farmers were trained by these trainers in participatory tree domestication techniques. The results are that over 200 communities are now involved and have developed at least 100 nurseries producing a diversity of improve tree planting materials of indigenous fruit and nut species with superior fruit and nut qualities (Figure 1).

Trained nursery operator using vegetative propagation techniques like marocting to multpy the best Cocoa trees within his plantation.

In all the concerned communities, farmers are integrating between 10 to 200 superior varieties of indigenous fruit and nut trees on farms per household within a network of about 10,000 farmers. The most popular niches for this practice observed include: home gardens; boundary trees and wind breakers; mini plantations; mixed with food crops; and as shade providing trees in perennial cropping systems such as, cocoa and coffee (Figure 2). However, in most cases the level of introduction is low and so the potential of a great number of tree species has not yet been fully exploited. Meanwhile, these farming systems could be enriched with superior varieties of indigenous fruit trees in ways that will improve food self-sufficiency and/or enhance nutrition and diversify rural households’ revenues, while expanding the natural resource based and potential carbon sinks.

The potential is great, but the challenge is determining how to scale-up. What are the next steps to expand these technologies that build on local knowledge of indigenous species, supply them to the millions of farmers around the world who rely on these species for their livelihood?

Additional Resources

Asaah, E.K., Z. Tchoundjeu, R.R.B. Leakey, B. Takousting, J. Njong, and I. Edang. 2011. Trees, agroforestry and multifunctional agriculture in Cameroon. International Journal of Agricultural Sustainability 9: 110-119

Pye-Smith, C. 2010. The fruits of success: a programme to domesticate West and Central Africa s wild fruit trees is raising incomes, improving health and stimulating the rural economy Nairobi, Kenya: World Agroforestry Centre

Simons, A.J. and R.R.B. Leakey. 2004. Tree domestication in tropical agroforestry. Agroforestry Systems 61:167-181

Tchoundjeu, Z., A. Degrande, R.R.B. Leakey, A.J. Simons, G. Nimino, E. Kemajou, E. Asaah, C. Facheux, P. Mbile, C. Mbosso, T. Sado and A. Tsobeng. 2010. Impact of participatory tree domestication on farmer livelihoods in west and central Africa. Forests, Trees and Livelihoods 19: 219-234

Dr. Ebenezar Asaah is Agroforestry Tree Domestication Scientist at the World Agroforestry Centre’s office for West and Central Africa in Cameroon. Dr. Zac Tchoundjeu is Principal Scientist (Tree Domestication) and the Regional Coordinator for West and Central Africa at the World Agroforestry Centre’s West and Central Africa Office in Cameroon.

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