关键词: 三峡库区, 消落带, 狗牙根, 种群密度, 生物量

Abstract: Dry matter weight and nutrient content are measured for 4 groups of needles and branchesof Korean pine.It is showed that fresh needles decompose more quickly than dead needles.The C/N ratio of branch changes slightly after 30 months of decomposition.Calculated nut-rients provided by medium intensity pruning of the 15 years man-made Korean pine forestare:N 21.0kg穐a^-1,P 2.7kg穐a^-1,K 6.8kg穐a^-1,Mg 2.6kg穐a^-1.The annual litterfallamount is 6.65t穐a^-1,which contains N 2.14kg穐a^-1,P 4.1kg穐a^-1,K 8.1kg穐a^-1 and Mg15.9kg穐a^-1.These are undiscountable nutrient sources for the forest floor.

Key words: Three Gorges Reservoir area, hydro-fluctuation belt, Cynodon dactylon, population density, biomass