林下植被抚育对樟人工林生态系统碳储量的影响

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

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0.62t·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0–10cm、10–20cm土层比未抚育林分分别降低了10.16g·kg–1和8.58g·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0–10cm和10–20cm土层分别降低了15.39t·hm–2和11.58t·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。

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 plan-tation. 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 （p0.05）. Carbon storage in soil was reduced by understory removal treatment in each interval of 0-60 cm depth with a de-crease 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 （p0.01） and 10-20 cm （p0.01） layers, respectively. However, the total forest carbon storage in the C. cam-phora 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.