Increase of leaf lifespan and nutrient resorption, and greater nutrient allocation to leaves may lead to an increase of above-ground nutrient-use efficiency and the maintenance of growth rate in nutrient-depleted environments. Here, we quantified the effects of these functional traits (leaf lifespan, resorption and nutrient allocation among organs) on the growth rate and tested the hypothesis that the effects vary in relation to tree size and type of element (N vs. P). To achieve this goal, we constructed an individual-based nutrient-budget model linking nutrient uptakes (nutrient demand) with growth rate and functional traits, and analyzed the model using the data collected from Bornean tropical forests. The model demonstrated that growth rate considerably increased with increasing leaf lifespan and nutrient resorption, and greater nutrient allocation to leaves at a fixed-nutrient uptake, and that the effects were lower for small saplings than large trees. N depletion decreased growth rate more than P did because tree species did not increase N allocation to leaves in N-depleted environments. Our results suggest that small trees are more susceptible to nutrient limitation, and that N than P exerts greater effects in tropical forest ecosystems.