间伐强度对柏木低效人工林灌草多样性的影响1）

研究了弱度（15％）、中度（25％）、强度（35％）、极强度（50％）和CK （0％）5种间伐强度对德阳市旌阳区33年生柏木（ Cupressus funebris）低效人工林灌草生长及其生物多样性的影响。结果表明：间伐1 a后，不同间伐强度下的林下植物种类、密度和生物量均有所增加；林下灌木层和草本层物种的丰富度指数、Shannon－Wiener指数和 Simpson优势度指数均随着间伐强度的增大而增大，其中，强度和极强度间伐增加最显著（ P＜0．05）。从短期的影响效果看，强度和极强度间伐有利于柏木低效人工林灌草多样性的提高。

Effetc s of Different Thinning Inten sity on the Undre story Diversity within Cupressus f unebris Low-efficiency Plan-tation

By 1-a in situ simulated experiment , we examined the short-term effect of 15%( T1) , 25%( T2), 35%( T3) , 50%( T4) and 0 ( CK) thinning on the understory ( shrub and herb ) diversities of 33-a low-efficiency Cupressus funebris planta-tion, located in Jingyang District of Deyang City , Sichuan Province .One year later , the species richness , density, biomass of understory increased slightly in all treatments .The species richness , Shannon-Wiener index , Simpson dominance index of shrub-and herb-layer were increased with thinning intensity , and the significant positive effects on diversity existed in T 3 and T4.Hence, the intense thinning could facilitate to increase the diversity of shrubs and herbs within low -efficiency C. funebris plantation .