杉木人工林连作生物生产力的研究

在全国杉木中心产区，选择不同栽植代数（1、2、3代），不同生长发育阶段（5、10、15、20a)及不同立地（14、16、18地位指数）的杉木人工林，进行不同栽植代数杉木人工林生物生产力的比较研究。结果表明：连栽导致了不同生长发育阶段杉木人工林生产力的明显下降，随栽植代数增加，不同生长发育阶段杉木林林分生物量逐代递减，林下植被生物量呈递增趋势，其中2、3代20a生杉木林林分生物量分别比1代下降20.24%和38.09%，3代比2代下降22.38%。同时林分树干生物量所占比例下降，根系生物量所占比例增加，连栽刺激了杉木根系生长发育，并有利于林下植被恢复。

STUDY ON BIOMASS PRODUCTIVITY OF CHINESE FIR PLANTATIONS AFTER SUCCESSIVE PLANTING

The biomass productivity of different generation plantations of Chinese fir was studied through the investigation of different generation, age and site plantations. The results are as follows:Successive planting results in significant biomass productivity decline of different aged plantations of Chinese fir.As planting generation increases, the stand biomasses of different aged plantations decrease, whereas underground vegetation biomasses increase. Compared to the first generation plantation, the stand biomasses of the second generation and the third generation plantations of 20-year-old decrease by 20.24% and 38.09% respectively. The stand biomass of the third generation plantation of 20-year-old decrease 22.3% compared to the second generation plantation.Moreover, proportions of stem biomass decrease proportions of root biomass increase along with increase of planting generation. Successive planting simulates develop of root and underground vegetation of Chinese fir plantations.