Abstract:

Abstract: Carbon density,storage and spatial distribution of three different age classes(4-year-ld,7-year-old and 11-year-old) of Acacia mangium plantation ecosystems were investigated in the city of Nanning,Guangxi.The results indicated that carbon density in different organs of A. mangium ranged from 455.4 g•kg^-1 to 494.5 g•kg^-1,which in the order as follows: bark＞stem or leaf ＞branch＞root.The vertical distribution of carbon density within the stand was in the following order: tree layer＞shrub layer＞herb layer. Carbon density in the 0～80 cm of soil increased with the stand age increase, and decreased with the inrease of soil deepness.The total carbon storages in three age classes of A. mangium plantation ecosystems were 117.63,176.70 and 202.08 t•hm^-2,respectively.Of the total storage of carbon,25.67%～50.91% was distributed in tree layer,1.62%～1.82% at herb and shrub layer,44.59%～69.84% at soil layer,only 2.68%～2.88% at litter layer. Annual net carbon storage at three age classes of A. mangium plantation was respectively up to 10.66,5.70 and 12.55 t•hm^-2a^-1 and 70.17%～74.58% of the total annual net carbon storage was distributed at tree layer,with the 44.59%～69.84% at little layer.Therefore, A. mangium plantation could obviously increase the carbon storage of ecosystem and prompt the potential capability of sequestrating atmospheric CO₂.

Key words: Key words: Acacia mangium plantation, age classes, carbon density, carbon storage, carbon distribution