Abstract: The response of 112 open-pollinated Chinese fir (Cunninghamia lanceolata (Lamb. ) Hook) families from southern China was evaluated for stem volume at 8 test locations. The AMMI (additive main effects and multiplicative interaction model) analysis revealed a considerable family X site interaction. The sites were grouped into four sets from the results of cluster analysis of mean family AMMI1 estimates and interaction PCA1, and among-site genetic correlations among sites. It is evident that delimitation of breeding zone for Chinese fir may be overlaid with the geographical zone if selecting on growth. One hundred and twelve open-pollinated families were clustered into four classes by their IPCA1 values and mean stem values. The consolidation of families would not appear to be corresponding with their origin.