<p>Tree architecture shapes forest structure and function. Functional traits reflecting ecological strategies may influence allometric relationships between architectural parameters across species and life stages, which remains poorly understood. We measured architectural parameters (tree height, crown width, crown depth) for 1309 individuals of 41 co-occurring tree species in a 20-ha tropical seasonal rainforest dynamics plot in Xishuangbanna, southwest China. Using Bayesian hierarchical models, we quantified species-specific allometric relationships, with which we further tested how functional traits covering mechanical, life-history, and leaf-economic dimensions correlated and how these correlations varied across ontogeny. Interspecific variation in tree architecture was primarily driven by allometric intercepts rather than slopes. Species with higher adult stature (<i>H</i>_max) and crown exposure developed slenderer stature but narrower, shallower crowns at given sizes. While denser wood consistently supported greater height and deeper crowns across ontogeny, the correlation between traits and crown dimensions tended to weaken from the juvenile to the adult stage. Our results uncover a trade-off between height growth and crown expansion, and reveal that ecological strategy may depend on life stages. Overall, the relationships between functional traits and tree architecture reveal multiple dimensions of species differentiation arising from variation in architectural and leaf-economic strategies among co-occurring tree species in tropical seasonal rainforests.</p>