Calorific value of plants is an important parameter for evaluating and indexing material cycles and energy conversion in forest ecosystems. Based on mensuration data of 150 sample sets, we analyzed the calorific value(CV) and ash content(AC) of different parts of Masson pine(Pinus massoniana) trees in southern China using hypothesis testing and regression analysis. CV and AC of different tree parts were almost significantly different(P<0.05). In descending order, ash-free calorific value(AFCV) ranked as foliage > branch > stem bark > root > stem wood, and AC ranked as foliage > stem bark > root > branch > stem wood. CV and AC of stem wood from the top, middle and lower sections of trees differed significantly. CV increased from the top to the lower sections of the trunk while AC decreased. Mean gross calorific value(GCV) and AFCV of aboveground parts were significantly higher than those of belowground parts(roots). The mean GCV, AFCV and AC of a whole tree of Masson pine were 21.54 kJ/g, 21.74 kJ/g and 0.90%, respectively. CV and AC of different tree parts were, to some extent, correlated with tree diameter, height and origin. Calorific value of plants is an important parameter for evaluating and indexing material cycles and energy conversion in forest ecosystems. Based on mensuration data of 150 sample sets, we analyzed the calorific value (CV) and ash content (AC) of different parts of Masson pine (Pinus massoniana) trees in southern China using hypothesis testing and regression analysis. CV and AC of different tree parts were significantly different (P <0.05). In descending order, ash-free calorific value (AFCV) ranked as foliage> branch> stem bark> root> stem wood, and AC ranked as foliage> stem bark> root> branch> stem wood. CV and AC of stem wood from the top, middle and lower sections of trees differed significantly. CV increased from the top to the lower sections of the trunk while AC decreased. Mean gross calorific value (GCV) and AFCV of aboveground parts were significantly higher than those of belowground parts (roots). The mean GCV, AFCV and AC of a whole tree of Masson pine were 21.54 kJ / g, 21.74 kJ / g and 0.90%, respectively. CV and AC of different tree parts were, to some extent, correlated with tree diameter, height and origin.