This study investigated the influence of various hardwood characteristics on enzymatic hydrolysis. Important hardwood species, including three Eucalyptus species, were comprehensively characterized using quantitative C-13 NMR, image analysis and fiber quality analysis. Hydrolysis efficiency from all the hardwoods was correlated to the wood chemical composition and lignin characteristics. Among the key wood components that control enzymatic hydrolysis efficiency, lignin content, enzyme adsorption on substrate and, the ratio of syringyl/guaiacyl (S/G) of the pretreated feedstock were identified as the most important. No wood morphological feature was found to have a significant influence on enzymatic conversion of the pretreated samples. (C) 2012 Elsevier Ltd. All rights reserved.