南亚热带不同树种人工林生态系统碳库特征

Carbon pool of different species plantation ecosystems in lower subtropical area of China

研究比较了我国南亚热带5个树种人工林生态系统的碳储量及分配格局,结果表明：在相似的生境条件下、林龄和经营管理措施相同,不同树种人工林生态系统碳储量表现出较大差异,其中以火力楠林具有最大的储碳能力,其碳储量为359.43 t/hm^2,其次是米老排林,为319.80 t/hm^2,红椎林、马尾松林和铁力木林碳储量差异不大,分别为225.87 t/hm^2、222.43 t/hm^2和207.81 t/hm^2。乔木层与土壤层是森林生态系统碳储量的主体,占生态系统碳储量总量的95%以上。不同树种林分乔木层碳储量以米老排林最高,为188.09 t/hm^2,其次是火力楠林,为176.44 t/hm^2,再其次是红椎林,为102.56 t/hm^2,马尾松林和铁力木林最低,分别为84.59 t/hm^2和84.01 t/hm^2。树种不同,树木器官碳储量分配各不相同,但是均以树干最高,其次为根或枝,再其次为干皮,叶最低。林下灌木层和草本层碳储量分别为0.036 t/hm^2～1.163 t/hm^2和0.027 t/hm^2～0.913 t/hm^2,地表凋落物层碳储量在9.54 t/hm^2～2.37 t/hm^2之间。不同树种人工林100 cm厚土壤有机碳储量以火力楠林最大,为179.59t/hm^2,而米老排林、红椎林、铁力木林和马尾松林之间差异不大,在117.21～127.28 t/hm^2之间。研究结果表明,南亚热带人工林具有较高的储碳能力,可发展成为高碳汇人工林基地。

With comparative method, the carbon storage and its distribution pattern of five species plantations system located at Shaopin Experimental Farm of Experimental Centre of Tropical Forestry in Pingxiang, Guangxi, China were investigated and studied. The purpose was to evaluate the potential carbon sinks of large sized trees in plantations, and to provide more perspective about commercial forest plantations that are being adaptively managed for timber production objectives in conjunction with carbon storage objectives. The results show that the carbon storages of different species plantation systems had greater differences under similar habitat, same stand age （27-year-old） and same management history, among them, Michelia macelurei stand had the greatest capacity to store carbon, its carbon storage was 359.43 t/hm^2, the next was Mytilaria laosensis stand, being 319.80 t/hm^2, carbon storages of Castanopsis hystrix stand, Pinus massoniana stand and Mesuaferrea stand was 225.87 t/hrn2, 222.43 t/hm^2 and 207.81 t/hm^2, respectively and theirs difference was insignificant; The majority of carbon storage was found in the tree layer and soil layer, accounting for over 95% of the total carbon storage of ecosystems; Litter floor contributed 0.87% ～ 4.29% carbon storage to the ecosystems. Under-story shrubs and herbs were in small contribution to ecosystem carbon storage, up to only 0.5%; Carbon storage of tree layer showed larger differences among different species forests, M. laosensis stand was the highest, for 188.09 t/hm^2, followed by M. macelurei stand, for 176.44 t/hm^2, and then followed by C. hystrix stand, being 102.56 t/hm^2, the Pinus massoniana stand and the Mesuaferrea stand were the lowest, for 84.59 t/hm^2 and 84.01 t/hm^2. Different species of trees had the different organ carbon allocation, but they are all the same law, that the trunk＇s was the highest, followed by the root＇s or the branch＇s, and then followed by the bark＇s, the leave＇s was the lowest; Carbon storage of shrub layer and herb layer was 0.036 t/hrn2 ～ 1.163 t/hm^2 and 0.027 t/hm^2 ～ 0.913 t/hm^2, that of litter floor was between 9.54 t/hm^2 and 2.37 t/hm^2; In the case of the soil, the carbon was stored mainly in the 0 to 50 cm layer, which accounted for 61.33% to 64.69% of the carbon stored in 100 cm depth of the soil, carbon storage declined as the depth of soil increased; The carbon storage in the 0 to 100 cm soil layer ofM. macelurei stand was the greatest, 179.59t/hm^2, higher than that of the other stands, and that ofM. laosensis stand, C. hystrix stand, M. ferrea stand and P massoniana stand was all most the same, about 120 t/hm^2. The findings suggest that the plantations in lower subtropical China have high biomass productivity and higher carbon storage capacity, particularly in M. macelurei stand and M. laosensis stand, because of abundant light and heat resources. Therefore, the plantations in low subtropical China can be into develop into high carbon sequestration artificial timber base, thus playing an important role for China＇s forestry response to climate change in current and future.