the difference of hemicellulose of NaOH-treated poplar processing residues were not significant with each other at 80 g/L, especially between 5.0% and 7.0%-NaOH treated poplar processing residues. The highest cellulose reduction of 73.1% and hemicellulose reduc- tion of 53.3% were observed at 65 g/L for the 7.0%-NaOH treated poplar processing residues and at 50 g/L as the same NaOH dose. Maybe cellulose and hemicellulose were continuously degraded during the process of digestion by the high alkali residue (Zhu et al., 2010).