桂东南柳杉人工林碳氮储量及其分配格局

以广西六万林场31年生3种密度柳杉(Cryptomeria fortunei)人工林为对象,对其碳、氮储量以及碳、氮分配格局进行研究。结果表明:低、中、高3种密度的柳杉人工林生态系统碳储量分别为355.72、417.21和378.71t.hm-2,氮储量分别为17.91、22.13和19.99t.hm-2,均表现为中密度﹥高密度﹥低密度;低、中、高密度植被层碳储量分别为127.71、101.98和100.12t.hm-2,分别为土壤层碳储量的56.01%、32.35%、35.94%,表现为低密度﹥中密度﹥高密度;植被层氮储量分别为1048.85、674.26和705.69kg.hm-2,为土壤层氮储量的6.22%、3.14%、3.66%,则表现为低密度﹥高密度﹥中密度。充分说明桂东南柳杉人工林生态系的碳、氮储量受林分密度的影响,且碳、氮储量主要分布在土壤层。

Carbon and nitrogen storage and their allocation pattern in Cryptomeria fortunei plantations in southeastern Guangxi of South China

Taking the 31-year-old Cryptomeria fortunei plantations with low,medium and high stand densities in the Liuwan Forest Farm in southeastern subtropical region of Guangxi as test objects,this paper studied their carbon and nitrogen storage and allocation pattern.The total ecosystem carbon storage in the plantations with low,medium and high densities was 355.72,417.21 and 378.71 t·hm-2,and the total ecosystem nitrogen storage was 17.91,22.13 and 19.99 t·hm-2,respectively,both with the order of medium density > high density > low density.The carbon storage in the vegetation layer of the plantations was 127.71,101.98 and 100.12 t·hm-2,accounting for 56.01%,32.35% and 35.94% of the soil carbon storage in 0-100 cm layer,respectively,and showing the order of low density > medium density > high density.The nitrogen storage in the vegetation layer of the plantations was 1048.85,674.26 and 705.69 kg·hm-2,and occupied 6.22%,3.14% and 3.66% of the soil nitrogen storage in 0-100 cm layer,respectively,following the order of low density > high density > medium density.Our study indicated that the carbon and nitrogen storage of C.fortunei plantation ecosystems in the southeastern Guangxi was affected by stand density,and most of the carbon and nitrogen storage was sequestrated in soil.