The complex experimental research of combustion dynamics of the swirling flame flow, developing by co-firing the renewable fuel (wood biomass) with fossil fuel (propane) is carried out with the aim to obtain clean and effective heat production with reduced carbon emissions in the products. The effect of propane co-fire on the formation of the swirling flame velocity, temperature and composition fields, combustion efficiency and the heat production rate is explored and analysed. The results of experimental study have shown that the propane supply into the wood biomass gasifier provides faster wood fuel gasification with an intensive release of volatiles at the primary stage of the swirling flame flow formation, while the swirl-induced recirculation with enhanced mixing of the flame compounds results in a more complete burnout of wood volatiles downstream of combustor with reduced mass fraction of polluting emissions in the products.