Abstract:The inverse distance method (ID) was used to interpolate the sterile seed rate of Cunninghamia lanceolata distributed in various sites in Fujian Province in order to establish rational seed production bases. A modified inverse distance method (MID) is presented which includes ID and inverse distance squares method (IDS). Based on sterile seeds collected from 25 sites, models of MID, ID and IDS were built. The results of cross-validation for the three methods showed that mean error and root-mean．square interpolation eror in MID were lowest， and the average accuracy being 88.91％ ．MID could be useful in the study of epidemic trend of C．1anceolata sterile seeds and its distribution, as well as for establishing seed production base in optimum habitats.
