不同栽植代数杉木林林下植被发育的比较研究

在全国杉木中心产区，选择不同栽植代数（1、2、3代）、不同发育阶段（5、10、15、20a)、不同立地（14、16、18地位指数）的杉木人工林，进行不同栽植代数杉木林林下植被变化的比较研究，结果表明：栽植代数对杉木林林下植被发育有较大影响，不同栽植代数杉木林林下植被种类、频度及生物量均存在明显差异。1、2、3代杉木林林下植被物种丰富度分别为69、54、59种，并未出现不同代数杉木林的特有种，但不同代数杉木林林下植被物种出现的频度不同；随栽植代数增加，杉木林林下植被生物量及其分积累均呈递增趋势，其养分浓度高于杉木凋落物，2、3代杉木林林下植被的养分积累分别比1代增加16．90％和37．49％，杉木林林下植被具有较好的养分富集能力。

Comparative Study on Underground Vegetation Develop of Different Generation Plantations of Chinese Fir

The underground vegetation of different generation plantations of Chinese fir (Cunninghamia lanceolata) are studied through the investigation of different generation, age and site. The results are as follows: underground vegetation development of Chinese fir plantations are greatly influenced by planting generation. There are significant differences among the underground vegetation species, frequencies and biomass of different generation plantations. Species quantities of the first generation, the second generation and the third generation plantations are 69, 54 and 59 respectively. There is not special species of different generation plantations. As planting generation increases, biomass and nutrient accumulations of underground vegetation of different generation plantations increase. Underground vegetation concentrations are higher than those of its litter. Compared to the first generation plantation, the nutrient accumulations of underground vegetation of the second generation, the third generation plantations increase by 6.96% and 37.49% respectively. Underground vegetation of Chinese fir plantation has higher capacity to accumulate nutrients.