以川西9a生柳杉人工林为研究对象,设置对照(CK,0%)、轻度间伐(T1,21.1%)、中度间伐(T2,36.9%)、重度间伐(T3,49.0%)共4种处理,观测抚育间伐对林木生长和土壤有机碳的影响,结果表明:间伐4年后柳杉胸径、树高、蓄积量年平均生长量均为间伐>CK,两者间均存在显著差异(P<0.05),胸径年平均生长量大小排序为T3>T2>T1>CK,各处理间差异显著(P<0.05),间伐样地各处理间树高和蓄积量年平均生长量差异不显著(P>0.05);T2与T3林内径阶株数占比向更高径阶集中;0~40 cm土层有机碳含量与碳密度均值T2与T3显著大于CK(P<0.05);抚育间伐可显著降低土壤容重、提高毛管持水量,土壤全N均值T2和T3显著大于CK(P<0.05),间伐样地0~20 cm土层有机碳含量和碳密度与全N及全P之间存在极显著相关性(P<0.01)。中等间伐强度(T2)能够获得较高的生态和经济效益。

This paper takes the 9-year-old Cryptomeria fortunei Plantation in Ya'an of Sichuan Province as the research object and sets up four kinds of thinning intensities,including control (CK,0%),light (T1,21.1%),medium (T2,36.9%) and heavy (T3,49.0%) thinning,with the aim to study the effects of thinning on tree growth and soil organic carbon.The results show that the average annual growth of DBH,height and volume of stands were thinned plot>CK after 4 years of thinning,and there was significant difference between both (P<0.05).The annual average growth of DBH was T3>T2>T1>CK,and there was significant difference between all treatments (P<0.05),but there was no significant difference between the annual average growth of height and volume of thinning sample plot (P>0.05).The number of trees in the DBH class tends to the higher DBH class concentration in T2 and T3 treatments.The mean values of soil organic carbon (SOC) content and carbon density T2 and T3 in 0-40 cm soil layer are significantly higher than CK (P<0.05).Thinning significantly reduces the soil bulk density and improves capillary water holding capacity.T2 and T3 are significantly different from CK at the mean value of soil total N (P<0.05).After thinning,the SOC content and density (0-20 cm) are significantly correlated to total N and P nutrient content of soil (P<0.01).The results show that medium thinning intensity (T2) could obtain greater ecological and economic benefits.