Abstract: Gross caloric values, ash contents, ash-free caloric values, cellulose, hemicellulose, lignin and benzene-alcohol extract contents were studied at different growth stages and in various organs of Robinia pseudoacacia Cl.‘Hennansis 8’. Results showed that: the leaf had the highest average gross caloric values and ash-free caloric values, and these values were relatively higher at the initial growth stage of the next year among the sampling period of time; the leaf had the highest average ash contents, and the contents were higher at the late stage of the next year. The orders of cellulose and hemicellulose contents were all trunk > branch> bark> leaf. The leaf had the most lignin, benzene-alcohol extract contents. Benzene-alcohol extract contents were appeared to be an inverted V distribution with the growth stages. Gross caloric values were not significantly negatively correlated with ash contents, cellulose and hemicellulose contents, and they were significantly correlated with lignin but not significantly with benzene-alcohol extract contents; Ash-free caloric values were significantly negatively correlated with cellulose and hemicellulose contents, and were significantly correlated with lignin and benzene-alcohol extract contents. In terms of the variation of caloric values, the best cutting period for energy forests was the initial growth stage of the next year among the five growth stages of ‘Hennansis 8’.

Key words: Robinia pseudoacacia Cl.‘Hennansis 8’, caloric value, ash content, cellulose, hemicellulose, lignin, benzene-alcohol extract