林地抚育对黔中地区杉木人工幼林生态系统碳储量的影响

Effects of tending on carbon storage in the ecosystems of young Chinese fir plantations at the middle region of Guizhou Province,southwestern China

林地抚育(松土、割灌、锄草)是提高人工林林分成活率,促进林木生长的重要措施,但对其固碳功能的影响研究仍鲜见报道。本研究以杉木人工林为研究对象,分析了林地抚育(松土、割灌、锄草)对黔中地区杉木人工幼林生态系统碳储量及其组分(植被层、枯落物层、作为主根系层的0~60 cm土壤层的碳储量)的影响。结果表明:林地抚育使得杉木人工林林木的保存率、林分郁闭度、林木胸径、树高等均显著高于对照林分,林木单株生长的固碳能力大幅提高,其碳储量是对照林分的4.93倍。抚育杉木人工幼林生态系统的总碳储量(106.37 t/hm^2)显著高于对照(78.61 t/hm^2),其中植被碳库储量(26.07 t/hm^2)是对照(4.64 t/hm^2)的5.62倍,抚育后枯落物碳储量较对照高0.38 t/hm^2。但是,林地抚育后表层土壤(0~10 cm)有机碳含量较对照下降5.44 g/kg,而10 cm以下土层较对照均表现为增加,土壤碳储量较对照总体增加3.30 t/hm^2。因此,造林初期林地抚育可促进林木生长,提高植被、土壤和生态系统的碳储量,显著增强杉木幼龄林的碳汇功能。

This study was conducted to quantify the response of carbon storage in forest ecosystems to the tending works,which are often necessary and important measures to promote the survival rate and growth of young trees. In this study,the density of organic carbon and its components（ above- and below-ground biomass C,forest floor C,and soil C at the layer of 0- 60 cm） were measured and compared between tended stands（ TS） and non-tended stands（ CK） of 10-year-old young plantation of Chinese fir（ Cunninghamia lanceolata） in the middle region of Guizhou Province of China. The results showed that the canopy density,survival rate,diameter at breast height（ DBH） and height of trees were higher in TS than in CK. The carbon fixing ability of individual trees was greatly enhanced,demonstrated by that the carbon storage of individual trees in TS was 4. 93 times of that in CK. The total carbon storage in the whole ecosystems of Chinese fir young plantation was also significantly elevated by the tending,from78. 61 in CK to 106. 37 t / ha in TS. The carbon storage components of young Chinese fir plantation ecosystems responded differently to tending works. The vegetation layer carbon storage was 26. 07 t / ha in TS,5. 62 times of CK（ 4. 64 t / ha）. The humus layer carbon storage was increased by 0. 38 t / ha in TP compared with CK. Compared with CK,the organic carbon content was decreased by 5. 44 g / kg in the0- 10 cm soil layer,the organic carbon content was increased in the soil layers below 10 cm in depth,and the organic carbon density in the 0- 60 cm soil layer was increased by 3. 30 t / ha in TS than in CK.Thus,it can be concluded that the measure of tending can enhance the tree growth,the carbon storage of vegetation and soil and the service of carbon sequestration of the ecosystem of young Chinese fir plantation in the studied region.