Abstract:In order to explore the effects of environments on nonstructural carbohydrates (NSC), we selected the top ten species of importance value to sample in each plot basing on the field investigation in six 60 × 60 m plots established in oldgrowth forest of monsoon evergreen broadleaved forest in Yunnan. The contents of the starch, soluble sugar and NSC in the foliages, twigs, stems and roots of the dominant tree species and environmental factors were measured, and the correlations between the environmental factors and the contents of the starch, soluble sugar and NSC were assessed. The results showed that: (1) the contents of starch, soluble sugar and NSC were 13.91%, 3.31% and 17.21% in monsoon evergreen broadleaved forest in Puer in Yunnan, respectively. The sequence of the starch and NSC contents in each organ were roots > stems > twigs > foliages, but the sequence of the soluble sugar content was foliages > roots > twigs > stems. Tree organs with the highest coefficient of variation in starch content, soluble sugar content and NSC content were the foliages (19.09%), stems (15.32%) and roots (16.30%), respectively. (2) The starch content in trees was significantly correlated with the litter thickness, soil pH and potassium; while the soluble sugar content was significantly correlated with the elevation and the soil physical and chemical properties. The starch contents in both Anneslea fragrans and Castanopsis hystrix were significantly correlated with the soil phosphorus. However, no significant correlations were found between the soluble sugar contents in A. fragrans and all the studied environmental factors. The soluble sugar contents in the roots and twigs in C. hystrix were significantly negatively correlated with soil pH and total potassium, respectively. Additionally, there were no significant relationships between the starch contents in Castanopsis echidnocarpa and all environmental factors. While the soluble sugar content in C. echidnocarpa was significantly negatively correlated with both the soil available nitrogen and phosphorus, and significantly positively correlated with slope, litter thickness and soil total potassium. (3) The soluble sugar content in monsoon broadleaved evergreen forest trees was significantly affected by elevation, soil organic matter and nitrogen using a linear regression analysis, and the starch content was significantly affected by soil pH. The results show that environment affects NSC in monsoon broadleaved evergreen forest, but different NSC component have different influence factors.