Clash of the titans: structure, diversity and farmer decision-making in cocoa agroforest development on forest margins, Cameroon uri icon

abstract

  • With support from the International Fund for Agricultural Development (IFAD) the World Agroforestry Centre, (ICRAF), Africa humid tropics has been testing hypotheses since 2003, that, multi-strata, diverse cocoa agroforests, managed according to farm erâ??s decisions and with options for deliberately incorporating high value indigenous trees can help fight Poverty and meet Environmental objectives; thus mitigation this â??clash of the titansâ?? of sustainable development in sensit ive forest margins of Cameroon. In order to better understand the tree integration co ntext and thereby make the process more relevant to farmer needs and sensitive to ecological questions, a study was carried out in some cocoa systems, with three overarching questions: (i) was large-scale integration of fruit and medicinal trees possible? (ii) How do we ensure that, a useful multi-strata structure develops? (iii) How do we balance ecological and socio-economic prerogatives? This anthropocentric, above ground, study evaluated the spatial relationships between fruit and medicinal trees above 5 m in height within cocoa systems an d their â??usefulnessâ?? to farmers. In total, 6 hectares of non-contiguous, cocoa plantations we re sampled. Data comprised of (i) the shortest horizontal inter-tree distances between species, (ii) the height classes frequenc y and distribution, and (iii) â??usefulnessâ?? perception of trees. In carrying out these studies a number of statisti cally testable assumptions were made. We assumed with farmers that, tree integration would be favoured by, (i ) greater variation in shortest horizontal, inter-tree distances; (ii) a 3:1 ratio with respect to fruit, to medicinal/timber/shade trees, of height classes 11-15m and â?¥ 20 m respectively, where the in termediate classes of, >5 â?¥ 10m (cocoa, young trees, etc) and >15 <20m (old fruit trees) were less important, would respond to a desirable th ree-tiered multi-strata architecture; (iii) that, a trade- off of at most 25% of diversity for â??socio-economicâ?? benefits was acceptable in balancing usefulness with diversity. We used the Coefficient of variation, Chi-squared hypothesized test and Simpsonâ??s biodiversity Indices to evaluate variability, and validity of second and third conditions respectively. Our results show the coefficient of variation in shor test inter-tree distances to be high (66%) suggesting both need for thinning and possibilities for integratio n. The Chi-square test of the 3:1 hypothesis held statistically, before farmer management decisions, but was rejected after. Following farmerâ??s decisions to â??maintainâ?? and â??eliminateâ?? trees, desp ite an expected loss of 37% of spec ies, Simpsonâ??s index showed a small gain of 2.17% largely due to a much larger gain of 63.5% in Evenness. Unsurprisingly our findings suggest that, opportunitie s for tree integration come with the need to thin- out less useful species most of which are taller trees. Meeting farmerâ??s prerogatives remain crucial though adapting these to a agreed model may yield better results for structure and diversity though at higher cost. The surprise is that despite looses in richness through ma ssive tree eliminations, an increase in equitability meant that biodiversity per se does not suffer. Thus the expect ed â??clash of the titansâ??: balancing conservation with livelihoods; may after all not be a fight to the death

publication date

  • 2007