【摘要】 【目的】为了解不同造林密度对杉木幼林碳储量空间分配及生物量垂直分布格局的影响，林分密度作为森林经营管理策略的关键一环，在提升森林碳汇功能、优化土地资源利用、促进生态恢复及增强森林经济产出等方面展现出显著优势。【方法】采用完全随机区组试验设计，对福建省顺昌埔上国有林场1年生杉木幼林开展833株/hm~2(D1）、1 667株/hm~2(D2）、2 500株/hm~2(D3）、3 333株/hm~2(D4）、6 667株/hm~2(D5）的密度造林，试验实施7年后，分析冠层结构，收集不同土层深度土壤，采用收获法调查林分内地上及地下垂直空间生物量，通过烘干法、元素分析-干烧法等测定方法，计算林分内各组分生物量、碳含量及碳储量，分析5种造林密度对杉木幼林各组分生物量空间分配格局、碳含量及碳储量垂直空间分布规律。【结果】杉木幼林生态系统碳储量土壤层显著大于乔木层和林下地被物层碳储量（P<0.05）；在地上部分中，乔木层碳储量总体变化范围为7.61～27.32 t/hm~2，占比最大，且碳储量在相同高度内随密度增大而增大。树叶和树枝生物量主要集中在树体中部2～6 m处，且碳含量最高；树干的生物量主要集中在树体下部0～4 m处。根系部分碳含量随密度增大而增大，生物量随土层深度的增加而减少。随着造林密度的增大，郁闭度和叶面积指数（LAI）呈现逐渐增加的趋势。对比不同的造林密度，D1密度下土壤层总碳储量最高，为182.95 t/hm~2,D2密度下杉木幼林平均胸径最大，D5密度下杉木幼林平均树高及枝下高最高，地上部分生物量及碳储量表现为最高。不同林分密度下杉木幼林土壤层碳含量为6.01～34.44 g/kg，土壤表层碳含量最高，且碳含量受土壤深度与造林密度共同影响。造林密度与树叶、树干生物量和碳储量均呈显著正相关（P<0.05）。【结论】6 667株/hm~2(D5）的造林密度相对最优，该密度下8年生杉木幼林树高及枝下高最高，在增加生物量的同时，一定程度上增加了幼林总碳储量，最大限度发挥杉木幼林的经济效益和碳固存能力，为杉木幼林在不同造林密度下的碳蓄积效率与生物量空间结构寻找最优配置策略。更多还原

【Abstract】 [Objective]This study aims to explore the spatial allocation of carbon stocks and the vertical distribution pattern of biomass in young Cunninghamia lanceolata forests with different silvicultural densities.Stand density,as a key part of the forest management strategy,has demonstrated significant advantages in enhancing the carbon sink function of forests,optimizing the use of land resources,promoting ecological restoration and strengthening the economic output of forests.[Method]Design of completely randomized block experiment was conducted silviculture at densities of 833 trees/hm² （D1）,1 667 trees/hm² （D2）,2 500 trees/hm²（D3）,3 333 trees/hm² （D4）,and 6 667 trees/hm² （D5） in a young 1-year-old C.lanceolata stand in the Pushang State Forest Farm in Shunchang,Fujian Province,China.After the experiment was implemented for 7 a,the canopy structure was analyzed and the soil was collected from different soil depths,harvesting method was used to investigate above and below ground vertical space biomass within the stand,Using methods such as the oven-drying method and elemental analysis-dry combustion method,the biomass,carbon content,and carbon storage of each component within the forest stand were calculated.The effects of five silvicultural densities on the spatial distribution pattern of biomass,carbon content and vertical spatial distribution of carbon stocks of each component in young C.lanceolata forests were analyzed.[Result]Ecosystem carbon stocks in young C.lanceolata forests were significantly higher （P<0.05） in the soil layer than in the tree layer and the understory vegetation material layer.In the above-ground fraction,the overall range of carbon stocks in the tree layer was7.61-27.32 t/hm²,which accounted for the largest proportion,and the carbon stock increased with density within the same height;The biomass of C.lanceolata leaves and C.lanceolata branches were mainly concentrated in the middle 2-6 m of the tree and had the highest carbon content,while the biomass of C.lanceolata trunks was focused primarily on the lower 0-4 m of the tree;C.lanceolata root fraction carbon content increased with density and biomass decreases with soil depth;as the afforestation density increased,the crown density and leaf area index（LAI） showed a gradual increase;Comparing different silvicultural densities,the highest total carbon stock in the soil layer at D1 density was 182.95t/hm²,the D2 afforestation density of young C.lanceolata stands had the largest mean diameter at breast height （DBH）,mean tree height and mean branch height were the highest under D5 afforestation density,the aboveground biomass and carbon stock of young C.lanceolata forests in the D5 afforestation density were the highest;carbon content in the soil layer of young C.lanceolata forests at different stand densities ranged from 6.01 to 34.44 g/kg,with the highest carbon content in the top layer of the soil.The carbon content was affected by the combination of soil depth and afforestation density.Afforestation density was significantly and positively correlated （P<0.05） with leaf and trunk biomass and carbon stock.[Conclusion]The afforestation density of 6 667 trees/hm² （D5） is relatively optimal,young 8a-old C.lanceolata stands at this density has the the highest tree heights and branch heights,which increases the biomass and increasing the total carbon stock of young forests to a certain extent,thus maximizing the economic benefits and carbon sequestration capacity of young C.lanceolata forests.This study identifies an optimal configuration strategy for the carbon storage efficiency and spatial structure of biomass of young C.lanceolata forests under different afforestation densities.更多还原