Biomass pyrolysis studies were conducted using both a thermogravimetric analyser and a packed-bed pyrolyser. Each kind of biomass has a characteristic pyrolysis behaviour which is explained based on its individual component characteristics. Studies on isolated biomass components as well as synthetic biomass show that the interactions among the components are not of as much significance as the composition of the biomass. Direct summative correlations based on biomass component pyrolysis adequately explain both the pyrolysis characteristics and product distribution of biomass. It is inferred that there is no detectable interaction among the components during pyrolysis in either the thermogravimetric analyser or the packed-bed pyrolyser. However, ash present in biomass seems to have a strong influence on both the pyrolysis characteristics and the product distribution.