Three commercially available biomass fuels, made of natural and waste wood, were fed in a pilot scale bubbling fluidized bed gasifier having an internal diameter of 0.381m and a maximum feeding capacity of 100kg/h. The experimental runs were carried out at about 850 degrees C and under values of the equivalence ratio between 0.20 and 0.30. The fluidized bed was generally made of natural olivine even though some runs utilized beds of dolomite or quartz sand. Measurements taken during each run include the gas composition, the content of tar in the syngas, the mass flow rate and composition of entrained fines collected at the cyclone and the characterization of bed material. The results indicate that the air gasification process is technically feasible with all the biomass tested. The olivine as tar removal bed catalyst provides for different results with waste and natural biomass fuels.