Z. serrata has been recognized as a dominant species of the lower slope and valley bottom, but in Kan-nami Old-growth Forest, the establishment of Z. serrata forest was also found on ridges and upper slopes. Tree-ring data obtained from 42 samples indicates similar initial establishment patterns in three micro-landform areas: most Z. serrata individuals established around the year of 1830, and no more major establishments are found after 1900. It most likely that Z. serrata's establishment is drove by severe historical disturbances for we at the same time observed fast initial growth rates after the establishment. We also checked various environment factors, and the results turn out soil Organic Matter Content (OMC), soil Moisture Content (MC) and soil depth are seen no distinct differences among ridges, upper slopes and valleys. Soil MC and OMC and soil depth values are quite high in ridge and upper slope areas same as in valley areas, providing favorable conditions for seeds to germinate. However, limited light condition in understory space and thick bamboo leaf layer may inhibit germination of Z. serrata's seeds. It is difficult to connect the initial establishment of Z. serrata with variations in environment conditions since no strong relationship is observed on basis of the result from Cluster analysis and PCA analysis in our study.