Study On The Energy Allocation Patterns Of Secondary Forests In Tropical And Subtropical Areas In Yunnan, Southwest China

Succession is a hotspot of ecology all the times, and energy plays an essential role in life activity. The objective of this study is to determine the allocation pattern of caloric values in some dominant species of the secondary forests that were evolved from deforestation of local tropical rain forests in Xishuangbanna and subtropical forests on the Ailao Mountains, Southwest China. The four communities in Xishuangbanna were Trema orientalis forest, Mallotus paniculatus forest, Macaranga denticulata forest and Millettia leptobotrya forest, which were 2-, 4-, 6- and > 15 years old respectively. Three plots of 20 m×20 m were established in each of the 4 forest types, in which species names, DBH of all trees whose diameters were over 3 cm were measured. Caloric values of 17 dominant tree species were observed. In the Ailao Mountains, we sampled 5 pioneer trees based on the data from previous investigates. Five sample trees comprised of one small, three intermediate and one large-sized tree were investigated for each dominant species. The sampled parts included foliages, branches, stems and roots. The caloric values of three replications for each sample part were measured with SDCM-IIIa oxygen bomb calorimeter, with error under100 J·g-1. Differences were tested by the t - Test. The results show that:1. Total number of species and species richness increased with forest ages. With the mature of communities, there should be more species diversity to abet energy dissipation.2. The mean caloric values of T. orientalis forest, M. paniculatus forest, M. denticulata forest and M. leptobotrya forest were 19182.11, 19474.81, 19551.38 and 19445.95 J·g-1 respectively. When the biomass of the community is low, the...