Influence of selective tree cutting, livestock and prescribed fire on herbaceous biomass in the savannah woodlands of Burkina Faso, West Africa

In West Africa policies for grazing, selective tree cutting and prescribed early fire in the savannah woodlands are rarely based on long-term experimental studies. The purpose of this study was to provide scientific evidence based on field data from two case studies for an informed discussion on the effects of various management options. The main findings were by and large specific for the species, the growth form and the location. This supports the argument for devolution of management responsibility to the local level where there is such site-specific ecological knowledge. Effects of selective tree cutting (50% of basal area), livestock (1–1.4 tropical livestock unit ha−1) and prescribed early annual fire on herbaceous biomass were studied in the state forests of Laba (shallow sandy soils) and Tiogo (deep clayey soils) in the savannah woodlands in the Sudanian Zone of Burkina Faso, from 1993 to 2001. The herbaceous biomass was analysed on three levels: total herbaceous biomass, per growth form (annual and perennial grasses and forbs) and for each of the four main species in the study areas (Andropogon pseudapricus, Loudetia togoensis, Andropogon ascinodis and Andropogon gayanus). At both sites, mean total biomass during the study period was reduced by the presence of livestock while it was not significantly affected by early prescribed fire or by selective cutting. There was interaction between the three treatments at both sites.