中文摘要：

福建三明米槠次生林皆伐后形成人促更新幼林（AR）与米槠人工幼林（CC）、杉木人工幼林（CL）,以保留的米槠次生林（CK）为对照,利用微根管法比较不同更新方式初期细根（直径≤2 mm）生物量和生产力的差异.结果表明：1年内,AR、CC、CL和CK细根的年均生物量分别为422.5、253.1、197.2和162.8 g·m^-2.4种林分细根总生产力大小为：AR（284.0g·m^-2·a^-1）〉CC（182.6 g·m^-2·a^-1）〉CL（136.7 g·m^-2·a^-1）〉CK（15.4 g·m^-2·a^-1）.AR和CC春季生产力最大,CL秋季最大,CK冬季最大.CC表现为其他植物细根生产力多于目标树种,CL表现为目标树种细根生产力多于其他植物.AR和CC总细根的月生产力与各月降水量呈显著正相关,CL的其他植物细根月生产力与月均气温呈显著正相关.3种更新方式下幼林细根的年生产力和年均生物量都以20-40 cm土层最大,且以0-1 mm细根占主体.采用人促更新方式的幼林细根生物量和生产力大于人工更新方式的幼林,人促更新方式更有利于增加林地有机物归还、提高土壤肥力、维持较高生产力和降低更新初期林地碳源.

英文摘要：

Fine root biomass and production in initial stage of three different regeneration approaches,i.e.,natural regeneration with anthropogenic promotion（ AR）,the Castanopsis carlesii plantation（ CC） and the Cunninghamia lanceolata plantation（ CL） on the clear-cutting sites of the secondary forest of C. carlesii（ CK）,in Sanming,Fujian Province,were investigated by using both minrhizotrons and the soil coring methods. The results of a year observation showed that the average fine root biomass was 422. 5,253. 1,197. 2 and 162. 8 g ·m^-2,and the fine root production was284.0,182.6,136.7 and 15.4 g·m^-2·a^-1for AR,CC,CL and CK,respectively. The maximum value of production was found in spring for AR and CC,in autumn for CL,and in winter for CK.Fine root production of other plants was higher than that of target tree species in CC,and vice verse in CL. There was a significant positive correlation between monthly fine root production and monthly precipitation in AR and CC. Significant positive correlation was found between monthly fine root production of other plants and monthly temperature in CL. The fine root under annual production and annual average biomass of these three young forests mainly distributed in the soil layer of 20-40 cm,and mainly in the diameter class of 0-1 mm. The study demonstrated that the biomass and production of fine root under anthropogenic promotion were greater than that of the plantation,and the method of anthropogenic promotion were more conducive to increase the returning of organic matter,improve soil fertility,and maintain a high productivity in initial stage of forest regeneration.