岷江干旱河谷-山地森林交错区典型人工林细根生物量及其碳储量特征

The Biomass and Carbon Stock of Fine Roots in the Representative Plantation in the Ecotone between Dry Valleys and Mountain Forest in the Minjiang River Basin

细根在森林生态系统的物质循环和能量流动中具有十分重要的和不可替代的作用。为了解岷江干旱河谷-山地森林交错带人工林生态系统功能，研究了该区青冈人工林（QF）、人工混交林（BF）、粗枝云杉人工林（SF）、沙棘灌木林（HP）和刺槐人工林（RP）五种典型森林群落细根的生物量及其碳储量特征。不同森林群落细根生物量和碳储量均随着土壤深度增加而降低，并与土壤发育程度和树种有关；细根主要分布土壤表层0～20cm范围内，平均占细根总量的87％，大于20cm细根也有分布，仅占细根总量的13％；QF、BF、SF、HP和RP细根的生物量分别为3820ks·hm^-2、2036kg·hm^-2、1855kg·hm^-2、1816kg·hm^-2和1144ks·hm^-2，碳储量分别为1．91MgC·hm^-2、1．02MgC·hm^-2、0．93MgC·hm^-2、0．91MgC·hm^-2和0．57MgC·hm^-2。

The t＇me root plays a significant and irreplaceable role in mass cycle and energy flow of forest ecosystem. The biomass and carbon stock of fine roots in five representative forests of Cyclobalanopsis glauca plantation （QF）, secondary forest （BF）, Picea asperata plantation （SF）, Hippophae rhmanoide shrub （HF） and Robinia pseudoacacia plantation （RP） were investigated to find out the forest ecosystem function in the ecotone between dry valleys and mountain forest in the upper reaches of the Minjiang Riv- er. The biomass and carbon stock of fine roots decreased with the increase of soil depth and depended on soil development and tree species. On an average, about 87% of fine roots grew in the upper soil layer from 0 to 20 cm, and the rest in deep soil. Biomasses of fine roots were 3 820 kg·hm^-2 in the QF, 2 036 kg·hm^-2 in the BF, 1 855 kg·hm^-2in the SF, 1 816 kg ·hm^-2in the HP and 1 144 kg·hm^-2 in the RP, respectively. Correspondingly, carbon stocks of five forest stands were 1.91 MgC ·hm^-2, 1.02 MgC ·hm^-2, 0. 93 MgC·hm^-2, 0. 91 MgC·hm^-2 and 0. 57 MgC·hm^-2 respectively.