杉木、木荷纯林及其混交林凋落物量和碳归还量

2005年5月-2007年4月,研究了福建省建瓯市水土保持科教园内19年生杉木人工林、木荷人工林和杉-荷混交林凋落物量和碳归还量.结果表明：3种人工林的年均凋落物量分别为2470.85、4171.96和4285.99 kg·hm^-2·a^-1,不同人工林中凋落物均以落叶为主,占林分年总凋落量的68.62%～87.26%.杉木人工林凋落物量在每年的4-5月、7月和12月出现3次较大峰值,而木荷人工林和杉-荷混交林凋落物量的峰值仅出现在每年的3月份.与人工纯林相比,混交林促进了阔叶树种的单株凋落物量增加,但抑制了针叶树种的凋落物量.落叶是3种人工林凋落物碳归还的主体,人工林碳年归还总量大小顺序与年均凋落量相同,其中杉-荷混交林最高(2.12 t·hm^-2·a^-1),杉木人工林最低(1.19 t·hm^-2·a^-1).与针叶和阔叶人工纯林相比,针阔混交林的凋落量大、碳归还量高,具有良好的碳吸存能力.

Litter fall production and carbon return in Cunninghamia lanceolata, Schima superba, and their mixed plantations

From March 2005 to April 2007, an investigation was made on the litterfall production and carbon return of Cunninghamia lanceolata, Schima superba, and their mixed plantations in the Jian’ou Science and Education Park of Soil and Water Conservation, Fujian. In these three plantations, the mean annual litter fall production was from 2470.85 kg·hm^-2·a^-1 to 4285.99 kg·hm^-2·a^-1, and dominated by leaf litter, accounting for 68.62%-87.26% of the total production. In C. lanceolata plantation, the litter fall production peaked in April-May, July, and December; while in S. superba and mixed plantations, this production only peaked in March. Comparing with pure plantations, mixed plantation had a higher litter fall production per tree of broadleaved S. superba while a lower litter fall production per tree of coniferous C. lanceolata. Leaf litter in the three plantations was the main body of the litter falls carbon return, and the total amount of the carbon return was the largest (2.12 t C·hm^-2·a^-1) in mixed plantation and the smallest (1.19 t C·hm^-2·a^-1) in C. lanceolata plantation, which was in accordance with the annual litter fall productionof the plantations. This study demonstrated that comparing with pure coniferous or broadleaved plantation, coniferous-broadleaved mixed plantation had higher annual litter fall production and carbon return, and thus, higher potential of C sequestration.