The use of biomass production and allometric models to estimate carbon sequestration of Jatropha curcas L. plantations in western Burkina Faso

Assessment of above-ground biomass The study was carried out from April 2012 to January 2013 and made use of dendrometical measurements, field observations and laboratory analyses. In order to determine annual net leaf-productivity, litterfall was collected from ten randomly-chosen J. curcas shrubs from two plantations of different ages (five from each plantation established in 2007 and 2008). At monthly intervals (from April 2012 to January 2013), the litter was collected and dried to a constant weight and the amount of litterfall per ha was calculated. For determination of total above-ground biomass, five 1000 m2 blocks were randomly chosen in each of the study sites for detailed measurements (girth of stem at 20 cm above the ground and the total plant height). This corresponds to a total of 390 individuals of J. curcas measured per study site. Plant density was determined by counting the number of plant in each sample plot. J. curcas individuals were divided into classes based on plant diameter at 20 cm above the ground and total height. Sample individuals were selected based on their abundance in a particular stem diameter class, so that the most abundant individuals and stem diameter classes were the most frequently sampled. In order to assess biomass production, destructive sampling of 38 individual plants was used in a wide range of diameters at 20 cm above the ground. stem girth at 20 cm above the ground, total height and crown diameters d1 and d2 (projection of the sapling above the ground, d1 being perpendicular to d2) were measured for each individual J. curas shrub. J curcas individuals were cut at the base, separated the biomass into two components, branches and leaves, and weighed these separately.