Abstract: Based on the biomass survey, this paper studied the characteristics of carbon accumulation and allocation pattern of a 28yearold Mytilaria laosensis plantation ecosystem in southwest Guangxi of South China. The carbon content in different organs of M. laosensis was in the range of 522.8-560.2 g·kg^-1, with the order of leaf (560.2 g·kg^-1) > stem (542.8 g·kg^-1) > root (530.9 g·kg^-1) > bark (530.8 g·kg^-1) > branch (522.8 g·kg^-1). The soil carbon content was the highest in surface layer, and decreased with increasing depth. The carbon storage in tree layer was 147.90 t·hm^-2, of which, stem accounted for 63.72% of the total. The total carbon storage of the M. laosensis plantation ecosystem was 285.36 t·hm^-2, and the allocation of the carbon storage in different components was tree layer > soil layer > litter layer > shrub layer > herb layer, with the carbon storage in vegetable layer being 1.1 times of that in soil layer (0-100 cm). The annual net carbon storage of the tree layer was 6.87 t·hm^-2·a^-1, which was dominated by the aboveground part.

Key words: impervious surface area index, linear spectral mixture analysis, spatiotemporal pattern, Yuqiao Reservoir Watershed.