Two installations with different biomass processing capacities (25-50 and 200-300 kg/h) were designed and constructed for air gasification of lignocellulosic biomass. This paper describes both installations as well as the experimental procedure. The influence of operating conditions on the amount and quality of products was determined. The results obtained from processing forestry waste are analysed. Values above 90% for mass conversion efficiency and over 70% for cold gas efficiency were reached.