The problem was studied because grey alder (Alnus incana (L.) Moenh) wood is the main raw material employed in smoking of meat and fish. Since pyrolysis is the first stage of burning and smouldering processes, the content and composition of extractives in grey alder wood and bark were determined, and the composition of the volatiles of the wood and extractives pyrolysis was investigated. It has been demonstrated that the content of cold and hot water extractives does not change during the three year storage at room temperature and in pile. During the 3 year storage the concentration of monosaccharides in cold and hot water wood extractives increases 1.3 to 1.7 times accordingly. The maximum concentration of sugars is in hot water extractives of grey alder bark of freshly cut wood. The concentrations of some compounds of the volatile products of grey alder wood pyrolysis are changing if wood specimens of different storage time are being pyrolysed. It has been found that the 2-hydroxyacetaldehyde yield increases with storage time. The concentration of levoglucosan (1,6-anhydro-β,D-glucopyranose) in volatile products of extractives-free wood pyrolysis increases 7 to 8 times in the comparison with the pyrolysis products of untreated wood. The concentration of 2 hydroxyacetaldehyde increases 1.4 to 1.7 times simultaneously with levoglucosan. It means that the elimination of extractives promotes both mechanisms of the cellulose decomposition simultaneously.