The paper deals with the changes of caloric value and ash content of the leaves in some mangrove species of China. The results were determined as follows.
1. In the area of Qiongshan in Hainan, the gross caloric value (20.62 to 18.97 kJ/g) decreased with the increase of ash content among different mangrove species. The ash-free caloric value of all species, however, was close to 21.5 kJ/g, with little variation.
2. For the same species, Kandelia candel, the ash contents were lower, and the gross caloric value were the higher in lower latitudes (less than 24˚N). The opposite is true for higher latitudes (more than 24˚N).
3. For K. candel ash content decreases and the caloric value increases as the tree grows. But the ash-free caloric value changes much less.
4. Seasonly changes of Caloric values (GCV and AFCV) of Kandelia leaves in Longhai of Fujian showed that in summer and fall was higher than that in winter and spring.