对27年生混交比例为2行杉木和1行观光木的混交林和杉木纯林群落细根分布的研究表明,杉木和观光木行间的杉木细根密度虽比杉木与杉木行间的低8.5％,但观光木细根密度则高152.09％,其细根总密度比杉木与杉木行间的大10.43％。混交林中杉木各径级活细根密度呈单峰型分布,均以5-10cm土层最大,而观光木各径级活细根主要分布在0-10cm土层内。纯林杉木各径级活细根密度亦基本呈单峰型分布,但峰值出现在10-20cm或20-30cm土层。不同树种不同径级死细根的分布均与其各自的活细根分布相似。混交林中灌木细根密度在30-40cm的土层最大,而纯林中的灌木细根集中于0-10cm的表土层;混交林和纯林中的草本细根均集中在0-5cm土层。与纯林的相比,混交林中杉木细根主要分布的土层明显上移,表层土壤细根所占比重增大,有利于更好利用土壤养分和提高群落生产力。Fine roots were measured by soil core sampler in a mixed plantation of 27-year-old Cunninghamia lanceolata (C) and Tsoogiodeudron odorum (T) in Fujian Province. Fine root density of C at interrow between C and T was lower by 8.5% than that between C and C, but fine root denstiy of T and total fine root density were higher by 152.09% and 10.43%, respectively. High density of living fine roots with different thickness of C in mixed plantation appeared at 5-10 cm soil depth, whereas that of T at 0-10 cm. Compared to mixed plantation, living fine root density in pure C plantation appeared at 10 -30 cm of soil depth. The distribution of dead fine roots had the same pattern. In mixed plantation, upward trend of soil layer with maximum fine roots of C was obvious, showing that mixed plantation had an advantage over pure plantation in nutrient absorption.中国博士后科研基金项目（1999-10）;;福建省科委重大基础研究项目（2000-F-004）;; 高等学校骨干教师资助计划项目;;福建省自然科学基金项目（B0110025
