Population spatial distribution patterns mirror the processes underlying forest community assembly and the ecological strategies facilitating species coexistence. Utilizing dynamic monitoring data from three 100 m × 100 m plots at the Cuigang Forest Farm in the Daxing'an Mountains,gathered in 2017 and 2023,and encompassing Betula platyphylla forests (pioneer stage),mixed Bp-Larix gmelinii forests (transition stage),and Lg forests (top stage),our analysis focused on the spatial patterns and interactions of dominant tree species,encompassing large trees,dead saplings,and surviving saplings. We employed pair correlation functions,summary statistics functions,and trivariate random labeling for this purpose. The findings reveal that the spatial patterns of large trees,dead saplings,and surviving saplings for both Bp and Lg species tend toward randomness with increasing scale. Throughout succession,at the small scale of ≤5 m,Bp large trees display uniform distribution,surviving saplings transition from aggregated to random distribution,and dead saplings display a distribution pattern that evolves from random to aggregated to uniform. Lg large trees and dead saplings show a random-aggregated-random distribution pattern at a small scale,while surviving saplings consistently exhibit an aggregated distribution at a small scale. Furthermore,intraspecific associations among both species are largely negative or insignificant,particularly for those species exhibiting aggregated patterns,which predominantly display non-significant intraspecific spatial associations. Density-dependent effects are commonly observed throughout the succession process,with density dependence for saplings trees of both species transitioning from negative to positive with succession stages. Finally,this study does not support the Janzen-Connell hypothesis,as no significant decrease in survival rates was detected for saplings trees approaching conspecific large trees at any successional stage. Instead,Bp saplings show increased survival rates when approaching conspecific or heterospecific large trees at various scales in the top stage. Lg saplings have a higher survival probability within the 0-15 m range of conspecific large trees in the transition stage and within the 5-15 m range of Bp large trees in the top stage.