A short-term laboratory incubation was conducted to study the variations of soil organic carbon and mineralizable organic carbon concentrations in four forest stands (Cunninghamia lanceolata plantation, Pinus massoniana + Lithocarpus glaber mixed forest, Choerospondias axillaries deciduous broadleaved forest, and L. glaber + Cyclobalanopsis glauca evergreen broadleaved forest) in a hilly region of central Hunan Province. In the four forest stands, the concentrations of soil organic carbon and mineralizable organic carbon and the proportion of soil mineralizable organic carbon to soil total org...