林下植被抚育对樟人工林生态系统碳储量的影响

以亚热带东部地区48年生樟(Cinnamomum camphora)人工林为研究对象, 探讨不同林下植被处理方式对植被和土壤碳储量的影响。研究结果表明: 1)林下植被抚育增加了植被的碳储量, 增幅为48.87%, 平均每年比未抚育林分增加了0.62 t·hm^-2; 2)林下植被抚育降低了土壤有机碳含量, 降低幅度介于4.79%-34.13%之间, 其中0-10 cm、10-20 cm土层比未抚育林分分别降低了10.16 g·kg^-1和8.58 g·kg^-1, 差异达到显著水平(p < 0.05); 3)林下植被抚育降低了森林土壤碳储量, 降低幅度介于1.98%-43.45%之间, 其中0-10 cm和10-20 cm土层分别降低了15.39 t·hm^-2和11.58 t·hm^-2, 差异达到极显著水平(p < 0.01)和显著水平(p < 0.05); 4)林下植被抚育降低了森林生态系统总碳储量, 降低幅度为4.27%, 但差异不显著。因此, 林下植被抚育虽有利于植被碳储量的积累, 但降低了土壤有机碳含量和储量。

Effects of understory removal on forest carbon storage in Cinnamomum camphora plantation ecosystem

Aims Our objective was to document the effects of different forest management strategies on carbon storage in both vegetation and soil in a Cinnamomum camphora plantation.
Methods We investigated the biomass of trees, shrubs, herb and the litter layer to calculate the carbon storage of vegetation and collected soil samples of 0–60 cm depth to analyze the soil carbon storage in a C. camphora plantation.
Important findings The carbon storage of vegetation was higher in understory removal stands than that of non-removal stands, with an increase of 48.87% and an increment of 0.62 t·hm^–2·a^–1. The soil carbon content was lower when the understory vegetation was removed, with a significant decrease ranging from 4.79% to 34.13%, and a significant decline of 10.16 g·kg^–1 and 8.58 g·kg^–1 in the 0–10 and 10–20 cm layers, respectively (p < 0.05). Carbon storage in soil was reduced by understory removal treatment in each interval of 0–60 cm depth with a decrease ranging from 1.98% to 43.45% and an especially sharp decline of 15.39 t·hm^–2 and 11.58 t·hm^–2 in 0–10 cm (p < 0.01) and 10–20 cm (p < 0.01) layers, respectively. However, the total forest carbon storage in the C. camphora plantation was not significantly reduced by understory removal treatment. Therefore, understory removal contributed to the accumulation of carbon storage in vegetation, but lowered the soil carbon content and storage.