陇东地区油松人工林碳密度及其影响因素

Carbon Density and Its Influence Factors of Pinus Tabulaeformis Plantation in Longdong Area

[目的]分析陇东地区人工林碳密度及其影响因素,为黄土丘陵区生态环境评价提供理论依据。[方法]采用样地调查与生物量实测方法,对陇东地区油松人工林碳密度进行了估算,并分析生态因素对油松人工林生态系统碳密度的影响。[结果]油松林各器官碳含量变化范围为48.58%-53.54%,各器官碳密度按从高到低的大小顺序依次为：树干〉树枝〉树根〉树叶〉树皮〉果实;灌木层叶、茎、根的碳含量分别为43.93%,45.62%,42.38%;草本层地上部分和地下部分碳含量为43.04%,39.77%;枯落物层未分解和半分解层碳含量为43.79%,38.83%;植被层碳密度按从高到底的大小顺序为：乔木层〉草本层〉灌木层。土壤层（0—100cm）碳含量随着土壤深度的增加而降低,且不同土壤层碳密度存在显著差异,以50—100cm碳密度最高。油松林生态系统平均碳密度为52.86t/hm^2,其空间分布排序为土壤层（75.15%）〉植被层（24.14%）〉枯落物层（0.71%）。[结论]油松人工林生态因子中,林分平均树高、平均胸径、郁闭度均与各层碳密度呈现极显著正相关性,林分枯落物未分解干质量与各层碳密度呈现显著正相关性。平均树高、平均胸径、郁闭度、枯落物未分解干质量是油松人工林生态系统碳密度的主要生态因子。

[Objective]To analyze the carbon density of Pinus tabulaeformis and its influence factors in Longdong area in order to provide theoretical basis for the evaluation of the ecological environment of the loess hilly region.[Methods]The carbon density of Pinus tabulaeformis was estimated and the influence of ecological factors on carbon density was discussed by the methods of plot investigation and biomass measurement.[Results]The carbon content in different organs of P.tabulaeformis ranged from 48.58%to 53.54%,and the average carbon density decreased in the order of stem〉branch〉root〉leaf〉cone.The carbon content of leaf,branch,and root in shrub was 43.93%,45.62% and 42.38%,respectively.The carbon content of above-ground and below-ground in herb was 43.04% and 39.77%.The carbon content of fresh litter and decomposing litter was 43.79%and 38.83%.The carbon density of vegetation layer decreased in the order of tree layer〉herb layer〉shrub layer.The average carbon content in the soil layer（0—100cm）decreased gradually with the increase of soil depth,and the carbon density had significant difference in different layers,and that in 50—100cm soil was the highest layer.The total carbon density of P.tabulaeformis ecosystem was 52.86t/hm^2,and the vertical distribution were：soil layer（75.15%）〉vegetation layer（24.14%）〉litter layer（0.71%）.[Conclusion]Ecological factors including average tree height,average diameter at breastheight and canopy density showed highly significant correlation with the carbon density of different layers of P.tabulaeformis plantation,and undecomposed litter dry mass showed significant correlation with it.The average tree height,average diameter at breast height,canopy density,and undecomposed litter dry mass were primary factors on the carbon density of P.tabulaeformis ecosystem.