Caloric values of dominant species in the different layers of lower subtropical monsoon evergreen broad-leaved forest at Dinghushan Mountain.
KUANG Yuan-wen; WEN Da-zhi; ZHOU Guo-yi; LIU Shi-zhong; ZHANG De-qiang. South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, P. R. China.
Investigation of the caloric values of the dominant species from different layers in lower subtropical monsoon evergreen broad-leaved forest in the Dinghushan Mountain may provide scientific foundamental data for studying energy flow and ecological efficiency. The values were measured by the PARR 1281 oxygenic bomb caloric-meter. The mean gross caloric values (GCV) of the 21 dominant species were in the range of 15.92～19.80 kJ/g. Cryptocarya chinensis was the highest and Canarium pimela was the lowest GCV species in tree layer 1, while the corresponding species were Machilus chinensis and Aporosa yunnanensis in tree layer 2.The lianas, Fissistigma glaucescens and Calamus rhabdocladus had the values of 19.73 kJ/g and 18.19 kJ/g, respectively. In the shrub layer, the highest GCV species was Cryptocarya chinensis and Aporosa yunnanensis the lowest. The mean GCV of the three herbaceous species was 15.92～17.52 kJ/g. The GCV and ash-free caloric value (AFCV) decreased in the following order: lianas, tree layer 1, tree layer 2, shrub layer and herb layer. The AFCV differed among various components. In tree layer 1, Castanopsis chinensis and Schima superba showed the highest values in barks, whereas Cryptocarya chinensis, and Canarium pimela had their highest values in the leaves. In tree layer 2, however, Aporosa yunnanensis showed the highest value in roots. For lianas, the AFCV decreased from the leaves, stems to roots. In the herb species, the AFCV aboveground was higher than the belowground. Minor differences in AFCV were observed for the same species (Cryptocarya chinensis or Aporosa yunnanensis) in different layers. The AFCV of the woody components tended to decease with age and diameter increment.