Abstract: In this study, the caloric value, nutrient content, and ash content in the stem, leaf, and root of four garden tree species Prunus mume Meiren, P. serrulata, Magnolia denudata and M. grandiflora were determined to explore the distribution characteristics of caloric value in different tree organs at different development stages, and related affecting factors. The results showed that the gross caloric value (GCV) and ash free caloric value (AFCV) in different organs of the tree species ranged from 17.02 to 21.93 kJ·g^-1 and from 18.42 to 22.57 k J·g^-1, respectively. Leaf and fine root had relatively higher GCV and AFCV than stem, and AFCV had a decreasing trend with the development of stem and root. P. mume Meiren and P. serrulata had higher GCV and AFCV than M. grandiflora and M. denudate. Both GCV and AFCV of fine root were significantly correlated with its nutrient and ash contents (P<0.01). With the development of root, the correlations of GCV and AFCV with organic carbon content declined gradually, while the GCV of different organs had the strongest correlation with total nitrogen content.

Key words: microbial response strategy, soil respiration, enzyme activity, water status