To explore the growth differences of Chinese fir plantations under different tree species configurations, to comprehensively improve forest quality and comprehensive benefits, and to provide relevant references for promoting the improvement of quality and efficiency of Chinese fir plantations.

Eleven sample plots of Chinese fir plantations were established in four counties in southern Hunan, Including 9 experimental plots and 2 control plots, continuous monitoring of basic information of the plot and forest growth index factors for 3 years.

1) In Chinese fir plantations with different tree species configurations, the growth of both Chinese fir and replanted tree species has shown an increasing trend year by year, better growth in middle-aged and near mature forests, the main tree species for replanting are Phoebe bournei, Liquidambar formosana, Cyclobalanopsis glauca, Schima superba and Cinnamomum camphora; 2) The effect of different forest reserve densities on the growth of Chinese fir and replanted tree species is significant, the average annual growth of the average breast height diameter, average tree height, and average tree height of replanted tree species in the forest stand are positively correlated with the reserve density of the forest stand; 3) The average breast height diameter of mature forest stands increases the most annually, the average annual growth of tree height in the middle-aged forest stage is the highest, the average breast height diameter and average tree height of replanted tree species show a negative correlation with the age group stage of the forest stand; 4) The replanting and growth of Phoebe bournei, Liquidambar formosana, Cyclobalanopsis glauca, Schima superba and Cinnamomum camphora in Chinese fir plantations showed stable performance, but when replanted with Houpoea officinalis, broad-leaved trees species perform poorly.

The improvement of quality and efficiency of Chinese fir plantations should be based on differentiated thinning and replanting plans according to forest age and density, Select local precious tree species Should be selected for replanting according to local conditions, dynamically adjust tree species structure and forest density, to select the optimal tree species configuration mode that is conducive to improving forest quality and efficiency.