不同林龄麻栎林地下部分生物量与碳储量研究

探讨不同林龄麻栎林地下部分根系的生物量与碳储量,为麻栎林的经营管理及碳汇管理等提供科学依据。以江苏省句容市不同林龄(幼龄林、中龄林、近熟林、成熟林)的麻栎林为研究对象,采用全根挖掘法获取麻栎各级根系及灌草层根系,并测定其生物量、碳含量,构建麻栎根系生物量模型,估算麻栎林地下部分根系碳储量及麻栎林群落碳储量。通过11种数学回归模型的比较,构建麻栎各级根系生物量幂回归模型,计算得到幼龄林、中龄林、近熟林、成熟林麻栎根系生物量分别为14.81t/hm~2、41.15t/hm~2、50.36t/hm~2、53.75t/hm~2,各级根系生物量大小顺序是:根桩粗根大根细根;灌木与草本植物根系生物量分别为0.48—1.71t/hm~2、0.13—0.60t/hm~2;不同林龄麻栎林群落根系生物量为15.42—56.06t/hm~2,且随林龄的增大而增大。麻栎根系碳含量大小顺序为:根桩粗根大根细根,且碳含量差异显著;灌木与草本植物根系碳含量分别为41.84%—43.79%、34.03%—38.48%,随林龄变化均无明显变化规律。麻栎林乔木根系碳储量随林龄增大而增大,幼龄林、中龄林、近熟林、成熟林根系碳储量分别为6.01t/hm~2、17.41t/hm~2、21.79t/hm~2、21.99t/hm~2;灌木与草本植物根系碳储量均随林龄增大而增大;幼龄林、中龄林、近熟林、成熟林群落根系碳储量分别为6.26t/hm~2、17.74t/hm~2、22.37t/hm~2、22.94t/hm~2,且乔木层灌木层草本层。麻栎林地下部分根系生物量与碳储量随林龄的增大而增大,幼龄林到近熟林生长过程中生物量与碳储量增加快速,近熟林后生物量与碳素积累缓慢,且与成熟林接近。

Underground biomass and carbon storage for Quercus acutissima forests of different ages

This study aimed to assess underground root biomass and carbon storage of forests of different ages and provide a basis for the management of forest operations and carbon sinks of Quercus acutissima forests. Quercus acutissima forests of different ages (young forests, half-mature forests, near-mature forests, and mature forests) were selected in Jurong, Jiangsu Province. The root excavation method was used to obtain the root systems of Quercus acutissima and shrub-grass layer roots were used to determine the biomass and carbon content to establish a regression model of the root biomass and to estimate carbon storage of the underground root and the community. On comparing 11 types of mathematical regression models, the root biomass regression model of Quercus acutissima was constructed, and the root biomass of young forests, half-mature forests, near-mature forests, and mature forests were determined to be 14.81t/hm², 41.15t/hm², 50.36t/hm², and 53.75t/hm², respectively, with the following order of root biomass at each level:root pile > thick root > large root > fine root; shrub and herb root biomass were 0.48-1.71t/hm² and 0.13-0.60t/hm², respectively; the root biomass of different stand age of Quercus acutissima community was 15.42-56.06t/hm², which increased with an increase in forest age. The order of carbon content in the roots of Quercus acutissima was root pile > thick root > large root > fine root, and carbon content was significantly different; the carbon contents of roots of shrubs and herbaceous plants were 41.84%-43.79% and 34.03%-38.48%, respectively, with no significant change in root carbon content of shrub-grass plants with age. Root carbon storage in the tree layer increased with an increase in age, and the root carbon storage of young forests, half-mature forests, near-mature forests, and mature forests was 6.01t/hm², 17.41t/hm², 21.79t/hm², and 21.99t/hm², respectively; the root carbon storage of shrubs and herbaceous plants increased with an increase in forest age; the communities of young forests, half-mature forests, near-mature forests, and mature forests were 6.26t/hm², 17.74t/hm², 22.37t/hm², and 22.94t/hm², respectively, in the order of tree layer > shrub layer > herb layer. Carbon storage and root biomass in the underground biomass of Quercus acutissima forests increased with an increase in forest age. Carbon storage and root biomass in the young forest to the near-mature forest increased rapidly with an increase in forest age, carbon and root biomass accumulation increased gradually after the near-mature forest stage, similar to that in mature forests.