This study aims to investigate the importance of steam to tar destruction during the volatile-char interactions. Steam was supplied in the absence and presence of nascent char during the pyrolysis/gasification of biomass at 850 degrees C. In the absence of char, steam has more significant effects on the reforming of large aromatic ring systems (e.g. >2 fused benzene rings) than small and isolated aromatics. In the presence of char, steam can significantly enhance the reforming of both large and small aromatic ring systems during the volatile-char interactions, especially when the steam-char reactions are also significant. The results indicate that the steam-char reactions are particularly inhibited in a thin char bed by the volatile-char interactions. It is believed that the steam-char reactions can produce additional active sties on the char, such as the radicals/intermediates of char gasification and/or the O-containing groups, to facilitate tar reforming during the volatile-char interactions. (C) 2014 Elsevier Ltd. All rights reserved.