6种林地有机碳密度垂直分布和有机碳含量垂直分布特征一致，随土层深度增加

6 kinds of organic carbon density forest vertical distribution and the vertical distribution of organic carbon content consistent with soil depth of organic carbon reduced density, maximum topsoil. Mainly due to a major role in plant roots concentrated topsoil, litter and soil microbe and humus layer decomposing organic carbon density contribution at the surface, and with the increase due to reduced soil depth, so carbon density of topsoil Big

The vertical distribution of organic carbon density in 6 forest areas and the vertical distribution of organic carbon content are the same, and the organic carbon density decreases with the increase of soil layer depth, with the largest topsoil. Mainly due to the concentration of plant roots in the soil surface, the decomposition of decayand matter and humus and soil microorganisms mainly contribute to the organic carbon density on the surface, and decreases with the increase of soil depth, so the carbon density of surface soil is high

The vertical distribution characteristics of organic carbon density of six kinds of forest land are consistent with that of organic carbon content. It is mainly due to the concentration of plant roots on the surface of soil, the contribution of litter and humic layer as well as the decomposition of soil microorganisms to the organic carbon density mainly acts on the surface, and decreases with the increase of soil depth, so the carbon density of the surface soil is large<br>