Abstract: To understand the spatial distribution characteristics of organic carbon in northern subtropical forest soils along an altitudinal gradient in Lushan Mountains of China, six and five sampling plots with a 200-m interval of elevation and covered by different vegetation types were installed on the southern and northern slopes, respectively in July-August in 2010 to collect soil profiles, with the soil thickness, bulk density, organic carbon content, and organic carbon density of 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm, and >40 cm layers measured. The soil organic carbon density was significantly affected by altitude and slope. On northern slope, soil organic carbon content increased with increasing altitude, and had significant negative correlations with soil bulk density and pH value. On southern slope, soil organic carbon content had no obvious variation pattern along the altitudinal gradient and had less correlation with soil bulk density and pH value, but soil organic carbon density decreased with increasing soil depth. The soil organic carbon density on northern and southern slopes was within the range of 7.07-10.34 kg·m^-2 and 6.03-12.89 kg · m^-2, respectively. The larger variation of soil organic carbon density along altitudinal gradient and soil depth on southern slope suggested that the destruction of original vegetation and the establishment of forest plantation could be one of the important factors affecting the spatial distribution of soil organic carbon.

Key words: Lushan, altitudinal gradient, forest soil, organic carbon density, litter, ecological stoichiometry, soil, stand age, leaf, Pinus sylvestris var. mongolica