Tree initial growth responds sequentially to seed mass and leaf traits in Chinese oaks

Plant growth is shaped by different ecological strategies, which are in turn related to relationships among multiple traits. The mechanistic pathways underlying sequential multi-trait associations with plant growth remain poorly understood. We conducted a common garden experiment to test the responses of early growth of Chinese oaks to seed mass and leaf traits, including 14 evergreen and deciduous species. We fitted logistic models to quantify growth rates, tested interspecific variation and relationships across traits and used Bayesian Phylogenetic Path Models to analyze growth pathways. We found large variation across leaf habits and across species within habits in all traits. Trait correlations and path models supported a two-stage sequential early growth model in which seed reserves enhance root collar growth first, and leaf functional traits such as larger leaves and higher specific leaf area promote seedling elongation. Leaf habit mediated the ecological strategies of oaks: deciduous species tended to exhibit more acquisitive strategies, while evergreen species were more conservative. Both deciduous and evergreen oaks exhibited large variation in ecological strategies and functional traits shaped by phylogenetically structured adaptations and trade-offs operating within each habit.