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Domesticating wild trees in Botswana

For millennia rural communities have harvested wild foods and medicinal plants (Richard Scrase)
For millennia rural communities have harvested wild foods and medicinal plants
Richard Scrase

In the Kalahari region of Botswana, wild foods such as marula and mongongo fruit have supported rural communities for millennia, with cultivated crops frequently taking second place in the hunt for food security. The reason, of course, is rainfall, which can at best be described as erratic: in many years, few if any food crops are planted at all. But the pressure on wild resources is forcing change, and with the prospect of lengthier, and potentially dangerous journeys gathering wild foods, communities have begun to explore a different path: domestication of useful wild plants.

The Useful Plants Project (UPP), an offshoot of the Millennium Seed Bank (MSB) based at Kew Gardens in London, is currently collecting and propagating plants from five dryland areas: Botswana, Kenya, Mali, Mexico and South Africa. Working with local communities, the project is training them to successfully store and propagate seeds, in an effort to improve food security for some of the most vulnerable people in the world.

Open gardens

In May 2009, Botswana's first UPP community garden opened in Tsetseng, a small village 40 km east of Kang in the centre of the Kalahari region. Forty tree species selected by local chiefs and plant experts had been reduced to a shortlist of 18, seedlings of which were provided by the project and planted in two hectares of sandy soil. Ongoing management will be by community members, with assistance from the Botswana College of Agriculture (BCA). Sited near a bore hole, the garden boasts a water tank, a shaded tunnel for seedlings, a storage hut for tools and, most importantly, a livestock-proof fence, all provided by the project. The site, covering five hectares in total, was donated by the community.

Management of the community gardens will be undertaken by community members (Moctar Sacende)
Management of the community gardens will be undertaken by community members
Moctar Sacende

The seedlings planted in the garden were germinated in Botswana using protocols developed at Kew, following several years of collaboration. In 2004, MSB Kew and the Botswana National Tree Seed Centre (NTSC), together with 15 other African tree seed centres, began a three-year project investigating seed biology of species useful to communities. Some species' seeds proved difficult to propagate, needing heat treatment, for example, before germinating. In response, MSB Kew developed a 'liquid smoke' technique to overcome seed dormancy, which has increased germination rates to over 80 per cent. This and other techniques are being passed on to African tree centres, enabling them to carry out seed-germination independently.

Informing choice

With people in the Kalahari previously unaware that their indigenous species could be cultivated, the garden is vital in demonstrating the value of tree domestication, both for conservation and use. Species such as mongongo and marula are held in particularly high esteem, mongongo for its oil-rich nuts, and marula for its long-lasting, vitamin C packed fruit, yet they have never before been cultivated in the area. By seeing how they perform, community members, both from Tsetseng and further afield, can make an informed decision about any species they may wish to cultivate in their home gardens. Final decisions will not be immediate, however, with the various tree species taking between five and ten years to produce a harvestable crop.

Afzelia quanzensis (pod mahogany) is just one of the useful species being investigated by the Botswana NTSC (Richard Scrase)
Afzelia quanzensis (pod mahogany) is just one of the useful species being investigated by the Botswana NTSC
Richard Scrase

In time, the garden is expected to earn money for the community from sale of various plant products. In Tsetseng, the villagers have already started adding value to some wild fruit, but finding reliable markets for these will be key. Mrs Direemang Kgola, the garden manager, recounts how she was asked to harvest two medicinal plants, Houdia, used for appetite suppression, and Devil's Claw, used for pain relief; the buyer then reneged on the deal, leaving her with unwanted material. Well aware of the prices such products fetch in Europe, she is now keen to establish direct links to these markets. "At the moment our work just benefits the middle-man," she says. Fortunately, the community garden does not need to be generating income immediately, with financial support coming from the UPP, and Debswana, a Botswana-based diamond company, also interested in providing funds.

Branching out

Next steps for the UPP in Botswana, according to country coordinator Dr Khola Mogotsi, include establishing more gardens and training local people how to collect and germinate seed. Assisted by her students at the BCA, Dr Mogotsi will also assess how different species cope with the different micro-climatic and soil conditions in the gardens. In the longer term, affordable systems for propagating the most successful species would need to be widely replicated, if the domestication of wild trees is to have an impact on the population at large. In so doing, the project could offer a wide range of benefits, improving food security, contributing to the economy, countering desertification and protecting biodiversity.

Written by: Richard Scrase

Date published: July 2009


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