The growth, biomass, nutrient content and accumulation as well as the vertical distribution of nutrient accumulation in Cunninghamia lanceolata plantation across densities of 1800, 3000, 4500 trees·hm-2 were stu-died in order to provide scientific basis for efficient cultivation of C. lanceolata plantation. The total amounts of nutrients accumulated in C. lanceolata plantation with 1800, 3000, 4500 trees·hm-2 were 1311.57, 2531.55 and 2307.33 kg·hm-2, respectively. There were significant variations among different densities. Under the same density, the order of nutrient content and accumulation in C. lanceolata plantation was total N > total K > total Ca > total Mg > total P. Moreover, the amount of nutrients in trunk and bark decreased with the increases of tree height. The amount of nutrient accumulation in persistent withered branch and leaf were allocated from middle to the upper part of tree, while the opposite was observed for fresh branch and leaf. N accumulation increased with the increases of stand densities, while the other nutrients first increased then decreased. The order of the amount of nutrient accumulation in trunk, bark, root, persistent withered branch, persistent withered leaf and litter among different densities was 4500 > 3000 > 1800 trees·hm-2, and was 3000 > 1800 > 4500 trees·hm-2 in fresh branch and leaf, and 1800 > 3000 > 4500 trees·hm-2 in understory. Under the densities of 1800 and 4500 trees·hm-2, the nutrient distribution ratio in bark was the largest, accounting for 21.6% and 19.4%. In 3000 trees·hm-2, the distribution ratio of fresh leaves reached its maximum, accounting for about 22.9%, and the next was fresh branches, which had a distribution ratio of about 17.8%. 3000 trees·hm-2 was the most appropriate density for nutrient accumulation and distribution in C. lanceolata plantation.
在对1800、3000和4500株·hm-2 3种密度杉木林生长调查及生物量测定的基础上,测定 3种密度杉木林各组分养分含量和养分积累量,研究其地上部分养分积累量的垂直空间分配,为杉木林高效培育提供科学依据。结果表明: 1800、3000和4500株·hm-2杉木林养分积累总量分别为1311.57、2531.55和2307.33 kg·hm-2,具显著差异。同一密度条件下,杉木林养分含量及积累量均表现为全N＞全K＞全Ca＞全Mg＞全P;树干、树皮养分积累量随树高的升高而降低。宿留枯枝、宿留枯叶养分积累量由树体中部转移到树体上部,而鲜枝、鲜叶养分积累量由树体上部转移到树体中部。随着林分密度增大,林分全N积累量呈上升趋势,而其他营养元素积累量呈先上升后下降的趋势。树干、树皮、树根、宿留枯枝、宿留枯叶、凋落物养分积累量表现为4500株·hm-2＞3000株·hm-2＞1800株·hm-2,鲜枝、鲜叶养分积累量表现为3000株·hm-2＞1800株·hm-2＞4500株·hm-2,林下植被养分积累量表现为1800株·hm-2＞3000株·hm-2＞4500株·hm-2。在1800、4500株·hm-2密度时,树皮养分分配比最大,为21.6%和19.4%;在3000株·hm-2密度时,鲜叶养分分配比达到最大值,为22.9%,其次为鲜枝,分配比为17.8%。3000株·hm-2密度是杉木林养分积累与分配最适密度。.
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