Understanding the interaction between bamboo and tree is required to explore the expansion of Moso bamboo (Phyllostachys edulis). In this study, we collected the spatial information of all individuals from a typical bamboo and broad-leaved forest interface (50×100 m) in Jingangshan National Nature Reverse, Jiangxi Province, China. Further, we used Programita software to analyze the spatial association between trees and bamboos, parent culms and new culms through O-ring statistical analysis. The results were as follows. (1) Bamboos were negatively associated with trees at all scales (within 10 m) in the whole interface. The range between bamboos and trees increased from 2-3 m in the bamboo forest to 2-9 m in the mixed forest. (2) Bamboos had variant associations with trees with different life ecotypes. They had no association with the deciduous tree species at any scale in the interface anywhere, while in 0-100 m interface, they were negatively correlated with trees at all scale except the scale of less than 1 m. Moreover, the scale that bamboos were negatively correlated with trees was larger than that with shrub in the early expansion stage, i.e. the front of bamboo expansion. (3) Associations between parent culms and new culms varied with expansion stage and forest interface. In 0-40 m zone of bamboo and broad-leaved forest interface, parent culms were positively correlated with young culm only at the scale of 1 m in 2013. In 40-80 m zone of the bamboo and broad-leaved forest interface, the range between the between parent culms and new culms decreased from 6-7 m in 2007 to 1 m and 3-6 m in 2013. The findings reveal that there is a significant negative association between bamboos and trees, and the association depends on the ecotype of trees, expansion stage as well as the relative density of both trees and bamboos. Bamboos expand into the broad-leaved forests through long-distance establishment of the new culms in the early expansion stage and the gradual population density increase in the late stage. The work can provide references not only for the determination extension and predictions of bamboo expansion, but also for the forest management to prevent from bamboo expansion. [ABSTRACT FROM AUTHOR]