Abstract:In order to select superior families of Castanopsis hystrix in southern China, the growth traits and genetic parameters of C. hystrix families at ages from 2 to 11 years were studied. The results showed that the average height, diameter at breast height (DBH) and wood volume among families had significant differences. The average height, diameter and wood volume growth of families were genetic controlled at medium level or above, which indicated high selection potential among or within families. Wood volume had large variation among families, followed by DBH and height. Family heritability and individual heritability gradually decreased with age increasing, and stabilized at 7- to 9-year-old. The genetic correlation coefficient of growth traits gradually increased with age increasing, and reached maximum at 7 years old and then tended to stable. The genetic correlation coefficients of plant height, DBH and wood volume were 0.9602, 0.9340 and 0.9849, respectively, so that 7-year-old was suitable age for early selection of families. Combined with early selection and character indexes, ten superior families of 11-year-old were selected, their average height, DBH and wood volume were 13.95 m, 14.34 cm and 0.1229 m3, respectively, and their genetic gains were 12.24%, 18.69% and 51.59%, respectively. Compared with contrast of the superior provenance, the 10 selected superior families showed certain advantage on tree form qualities, such as stem straightness, fullness, branching angle, the biggest branch and crown breadth, which increased from 7.71% to 12.94%.