The challenge of HIV/AIDS: Where does agroforestry fit in? - World ...

Chapter 2: Trees and markets for agroforestry tree products13Nations Environment Programme’s Conventionon Biological Diversity (Leakeyet al. 2003; Simons and Leakey 2004;UnsustainablecroppingLoss of incomefrom wildlifeand plantsLoss of incomefrom cropsExternal factors:war, environmentaldisasters, etc.HIV/AIDSDeforestationTchoundjeu et al. 1998), by recognizing therights of local people to their indigenousknowledge and traditional use of nativePovertyEcosystem degradationand soil erosionLoss of biodiversityBreakdown of ecosystem functionLoss of crop yieldsMalnutritionDeclining livelihoodsOvergrazingBreakdown ofnutrient cyclingand loss of soilfertility/structureIncreasedtransport ofnitrates towater tableIncreasedhealth risksFigure 1. The cycle of biophysical and socioeconomic processes causing ecosystemdegradation, biodiversity loss, and the breakdown of ecosystem function, in agriculturalland in many tropical countries.plant species, and to benefit from commercialdevelopment of this knowledge.The extraction of fruits and medicinalproducts from indigenous trees by huntergatherersis a traditional practice in mosttropical regions (Sullivan 1999). It has alsobeen noted that farmers frequently maintainindigenous fruit and nut trees withintheir farming systems and sell the productslocally. Yet despite these observations, andthe findings of the species prioritizationprocess, international donors were initiallysceptical about investing in new crop species.This scepticism perhaps stemmedfrom a deep commitment to the GreenRevolution, coupled with a top-down approachto rural development in the tropics– still evident in the on-going pursuit ofnew biotechnological solutions (Lipton1999; McCalla and Brown 1999).As proof, a study of the frequency distributionpatterns of traditional species foundthat subsistence households are indeedcommitted to their traditional food species(Leakey et al. 2004). This conclusion hasbeen corroborated by the quantificationof the numbers of indigenous fruit treesin farmers’ fields in Cameroon, especiallyon small farms (Degrande et al. in press;Schreckenberg et al. 2002). In Benin, relativedensities of widely used species aretypically higher in farmers’ fields than inthe natural savanna vegetation because ofpreferential retention by farmers (Schreckenberg1999). Interestingly, evidence fromSouth Africa indicates that the yield ofmarula (Sclerocarya birrea), a traditionallyimportant indigenous fruit tree, is increasedby 5- to 15-fold through cultivation inhomestead plots and fields (Shackleton etal. 2003a). Mean fruit size is also greaterfrom trees in these plots, again with someevidence for domestication by farmers(Leakey 2005; Leakey et al 2005a; 2005b).