ObjectiveThis paper analyzes understory species diversity, soil physicochemical traits and their relationships in the close-to-nature management of Chinese fir (Cunninghamia lanceolata) plantation.

MethodPlant species composition and diversity (richness index, Simpson index, Shannon index, and Pielou index) in disturbed communities were measured, and the variation of soil properties and their correlation with diversity were evaluated.

ResultThe results showed that species density and composition showed significant difference among the shrub layer and herb layer. With the increases of management intensity, species number and diversity in the tree and herb layers first increased, and then decreased. Both of them increased with the increase of density, with the maximum value presented at the model (450−600 tree/ha). Except for soil pH, the concentrations of total nitrogen, total phosphorus, total potassium, available potassium, and organic matter and soil moisture contents were closely related to shrub and herb layer diversity index.

ConclusionOur results indicated that there were correlations between soil environmental factors and plant diversity, with the correlations between soil total phosphorus, total potassium, available potassium, organic matter, and species diversity of community being significant. Meanwhile, the moderate intensity of management could increase species diversity in the understory and improve the soil physicochemical property. The results suggest that the density at 450−600 tree/ha and 30−40 tree broad-leaves replanting would be more beneficial to improve the stability of species diversity and soil fertility．