The study looked at how planting different tree species in degraded shrub forests in China affects the amount of easily-oxidized carbon and other organic matter in the soil. They found that after planting new trees, the soil had more total organic carbon and light fraction organic matter. Water-soluble organic carbon didn't change much. The type of tree species affected the ratios of different types of organic carbon in the soil. The amount of organic carbon in the soil was strongly linked to soil nutrients, especially in the mixed stand of Schima superba and Cyclobalanpsis glauca.