Field data and genotypes at five microsatellite loci of 281 Cercidiphyllum japonicum adults of a population distributed over a ca. 80 ha along a stream and 755 C. japonicum current-year seedlings sampled at approximate center of the populatoin. The population is located in Iwanazawa Forest Reserve (43°13′N, 142°34′E), University of Tokyo Hokkaido Forest, in central Hokkaido, Japan.