The trait-based approach has long been crucial for understanding and predicting seedling dynamics in forest ecosystems. However, the complex architecture of trait networks governing these dynamics has been scarcely explored. The relationships among plant traits, reflecting plants’ overall life strategies, can offer deeper insights into plant performance than traditional trait-based analyses. Focusing on trait network architecture and traits themselves helps better understand the seedling-to-sapling transition. During a 12-year period, we carried out a field census in a subtropical forest. Using a demographic progress model, we evaluated two key population-level metrics for 26 species: the time for seedlings to reach the 2-meter sapling stage and their early-growth survival period. We constructed plant trait networks with 16 leaf, stem, and root traits and explored their connections with population vital rates. Our results showed that newly recruited seedlings took 17–81 years to become saplings, with a survival span of 1–4 years over a 5-year observation period. Network centralization was negatively correlated with the transition time but did not explain early-stage survival variation. Species with acquisitive strategies exhibited shorter transition time and a shorter survival period. Hub traits with high connectivity, such as root tissue density and leaf dry matter content, were more influential in determining the transition time. Overall, our study highlights the importance of trait network centralization and hub traits. By integrating population characteristics into community structure, this study provides new ecological insights, improving our understanding of plant trait-population interactions and offering implications for forest management and conservation.