Local communities in southern Africa derive many benefi ts from marula [Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro]. These include the contribution of this species towards health, nutrition, food security and conservation by sharing local skills and knowledge related to it. Marula fruits can be eaten fresh, squeezed to make juice, brewed in traditional beer or used to make jam and jelly. The kernels are also edible and can be pressed to extract oil for cooking and cosmetics, i.e., for skin and hair application. The bark, roots, seeds and leaves are exploited for traditional medicinal purposes. Marula has acquired signifi cant commercial value since its fruits and other products have entered local, regional and international trade in southern Africa. To diversify fruit production and satisfy the increasing demands for this resource, several domestication initiatives have been carried out at regional and international levels. The accumulated knowledge and skills relevant to the establishment and commercialization of marula therefore provide an effective guide in areas where marula remains undomesticated or underutilized. We discuss the great importance of marula in southern Africa to reveal its great potential to regions where it remains unexploited.

Faidherbia albida is an ideal agroforestry tree commonly intercropped with annual crops like millet and groundnuts in the dry and densely populated areas of Africa. With its peculiar reverse phenology, it makes growth demands at a different time from that of crops. In addition, it deposits great amount of organic fertilizer on food crops. Leaves entering soils are comparable to fertilization of almost 50 t·ha −1 ·year −1 of manure in dense stands of 50 large trees per ha. These nutrients help maximize agricultural production and reduce the need for a fallow period on poorer soils. Research has shown that millet grown under F. albida yielded 2.5 and 3.4 fold increases in grain and protein, respectively. Animals eat pods which contain mean amounts of crude protein of 20.63% and carbohydrate of 40.1% in seeds. Moreover, the continued existence of F. albida in agroforestry parklands as in Ethiopia and Mali signifi es the success of traditional conservation measures. Modern scientists have also developed much interest in the role of agroforestry in maintaining long-term biological balance between agriculture and livestock production systems. To ensure food security, which still remains a major challenge in sub-Saharan Africa, and concurrently minimize environmental degradation, promotion of agroforestry that specifi cally involves indigenous trees is crucial. We discuss the prospective role of F. albida in alleviating poverty while simultaneously protecting the environment from factors associated with, for example, deforestation and loss of biodiversity. The overall aim is to promote wide-scale adoption of F. albida as a valuable tree crop in farming systems, particularly in those areas where it remains unexploited.

In Africa, rural people depend heavily, if not exclusively, on medicinal plants and indigenous healthcare knowledge to meet their medical needs. Over 80000 fl owering plant species are used medicinally worldwide. Amongst them are the underutilized Ziziphus species in the Rhamnaceae family. In terms of abundance and economic value, Z. jujuba and Z. mauritiana are currently the most important, especially in China and India where they are cultivated and exploited for medicinal use and their edible fruits. We examined a related common species widely distributed in Africa, Z. mucronata, whose economic value has not, as yet, been explored. Local people in various African countries use its different parts to cure a large number of diseases, many of which are similar to those treated with Z. jujuba and Z. mauritiana. Several studies have shown that Z. mucronata has cyclopeptide alkaloids, i.e., mucronines F, G and H, with antibacterial properties. Conservation strategies to sustain and maximize the benefi ts of Z. mucronata to people are proposed.

In order to identify the relationship between diurnal changes in the net photosynthetic rate (P n ) of Pueraria lobata and environmental factors, diurnal changes in the P n of leaves of two P. lobata cultivars were measured using a CIRAS-1 portable photosynthesis measurement system (PP-Systems, UK). The results show that diurnal changes in P n of both cultivars could be interpreted as double-peak curves, indicating the occurrence of an obvious midday depression. Further analyses indicate that the correlation between P n and stomatal conductance was positive and extremely signifi cant (p < 0.01). The correlations of P n with intercellular CO 2 concentration and transpiration rate were positive and signifi cant (p < 0.05), while the correlations of P n with air and leaf temperatures were negative and signifi cant (p < 0.05). The results indicate that among the factors affecting photosynthetic properties, some can be grouped as stomatal limitations while others are non-stomatal limitations.