Africa agricultural system is dominated by smallholder farmers who rely directly on it to meet their livelihoods .Increasing unsustainable land management and resource degradation is likely to cause climate change related risks as a result of low vulnerability to disasters.

Trees are important in climate change mitigation and reducing vulnerability in small-holder farmers in Africa .It is important more than ever to re-double our effort in promoting agroforestry practices to protect and rehabilitate the environment , reduce the emissions of green house gases and provide small-holder farmers with sustainable ways of increasing their production and meeting their livelihood needs .

At International Center for Research in Agroforestry / ICRAF headquarters in Nairobi researchers are working to identify which appropriate tree species to grow in Africa and through out the world by, locating seed suppliers, learning about how to maintain quality seeds and seedlings or assessing genetic variation using molecular markers thus provide a link and information to different .Promoting agroforestry use of multipurpose trees can be a solution to food security, environmental conservation and income generation among smallholder farmers in Africa.

Multipurpose trees in agroforestry context are trees and shrubs that are deliberately grown and managed for more than one preferred use,product or a service. Cultivation of multipurpose trees is economical because they supply food in the form of fruits, nuts or leaves hat can be used as a vegetable while at the same time supplying firewood and improving the soil nutrients through nitrification process.

Amy Ickowitz studies proves there is a relation ship between dietary quality and tree cover in Africa from capturing the higher quality of diets for the children who live in the communities in which the trees are found. In 2012, the Food and Agricultural Organization estimated that 868 million people in the world did not consume sufficient food energy (calories), but that micro nutrient deficiency affected over 2 billion people (FAO et al., 2012). Micronutrient deficiency is often called the "hidden hunger" because it can occur even when diets include an adequate amount of energy (calories). Iron, vitamin A, iodine and zinc are the micronutrients most commonly deficient in diets around the world (WHO, 2000 and UN, 2004).

Lately there has been efforts to study the fruit tree portfolio by ICRAF.The approach involves cultivating a set of fruit trees that is carefully designed to supply nutritious fruits to eat throughout the year, for diverse diets and improved health. The fruit tree portfolio for a particular locality is designed to provide for year-round fresh fruits for household's requirements of vitamin C and pro-vitamin A, both essential nutrients. Because the trees in the portfolio have different harvest seasons spanning the entire calendar year, they provide a year-round supply of at least one fruit species per month for the household. 

More reading and references :

http://blog.worldagroforestry.org/index.php/2013/08/07/the-little-understood-indigenous-african-fruit-trees/

Agroforestry - The Future of Global Land Use - edited by P.K. Ramachandran Nair, Dennis

 Garrity