Trees on farmlands in the western central part of Senegal: implications for a carbon project

Abstract

Trees are rapidly disappearing from agrarian landscapes in many tropical countries, a severe problem to rural populations, who depend on wood and non-timber forest products (NTFP) for their livelihoods. The aim of this study was to determine tree density, diversity, biomass and carbon stock in farmlands in Senegal and to gain insight in the socio-economic determinants of the tree cover. An allometric model was developed to estimate the average above ground biomass (AGB) based on field investigations of 235.5 ha of agricultural fields. In total, 25 tree species were recorded with an average density of 1.6 tree ha-1 and a canopy cover of 1%. The AGB was 8.9 t. ha-1 corresponding to 4.45 t C ha-1. A single species, Cordyla pinnata, accounted for 50% of all the trees censured. Investigations of google Earth images showed considerable change in tree density during the investigated periods (2004, 2009 and 2013). The tree density decreased at the rate of 3% per year-1 from 2004-2009 and 6.4% per year-1 from 2009-2013. Based on these results, all the trees would be lost in 30 years from 2009 and in 16 years from 2013 if this trend continues. Informants were generally interested in increasing the number of fruit trees. On average, they were willing to allocate 19% of their land for planting of new trees. Tree planting, however, has not been traditionally considered an option by the landowners, since livestock damage on young trees was too big and fencing not an option, but the recent years tree planting with certification for carbon sale has been initiated with support from outside.

Keywords: Africa, forest resources, deforestation, local management, woody biomass.