The aim of this study was to demonstrate maintenance mechanisms of bamboo forests by investigating emerging and survival of culms in an abandoned Phyllostachys bambusoides stand. For this purpose, the spatial distributions of culms including bamboo sprouts and the spatial correlations between different cohorts of the culms were analyzed by L-function transformed from Ripley’s K-function. From the results, it was observed that the bamboo sprouts showed aggregated distribution, and the distribution changed into random distribution in the growing stage of current year culms because of natural thinning in the growing stage of bamboo sprouts. Furthermore, these current year culms showed dissociated distribution to current year culms emerging in the next year. Thus, the stand is likely to have self-regulating function of the density in a cohort of new sprouts. Additionally, it is probable that the stand effectively fills a space with culms by exclusively positioning of current year culms between different cohorts.