Background Studying the distribution patterns and factors that influence soil organic carbon is of great significance for enhancing forest carbon sink and soil and water conservation functions. Authors observed and analyzed the distribution of soil organic carbon and active organic carbon fractions in various forest types.

Methods Soil in 0–60 cm layer for four forest types in Jiufeng National Forest Park, namely Platycladus orientalis forest, Pinus tabuliformis forest, Quercus variabilis forest and Pinus tabuliformis & Quercus variabilis forest, were selected to analyze the effects of forest types on soil carbon sequestration, and to determine the key factors of soil organic carbon changes using redundancy analysis.

Results 1) Except for the 20–40 cm soil layer, the four forest types had a significant effect on the soil organic carbon mass fraction of each soil layer, and the soil organic carbon contents of the P. tabuliformis & Q. variabilis forest and Q. variabilis forest was significantly higher than that of P. orientalis forest and P. tabuliformis forest (P < 0.05). 2) The impact of different forest types on the active organic carbon contents was mainly manifested in the soil surface, and the active organic carbon content of the P. tabuliformis & Q. variabilis forest and Q. variabilis forest was higher than that of P. orientalis forest and P. tabuliformis forest. 3) Soil total nitrogen was the main factor affecting the distribution of soil organic carbon and active organic carbon in P. orientalis forest, Q. variabilis forest and P. tabuliformis & Q. variabilis forest. Soil available phosphorus and available potassium were the main factors affecting the distribution of soil organic carbon and active organic carbon in the P. tabuliformis forest.

Conclusions The P. tabuliformis & Q. variabilis forest and Q. variabilis forest have strong carbon sequestration capacity, this may provide the support of carbon sequestration and soil and water conservation in the study area.