Abstract: To investigate the effects of silicon(Si)fertilizer dosage on the growth and nitrogen(N) and phosphorus(P) allocation in tree species of different life forms,a pot experiment was conducted using one-year-old seedlings of Cunninghamia lanceolata, Betula fujianensis and Phoebe bournei. Soil was treated with calcium silicate(CaSiO₃) at varying concentrations. The key findings were as follows:①silicon application significantly enhanced the relative growth of seedling height and basal diameter. Compared to the control, the mean relative height increment increased by 86.4% and 85.0% under the Si₂₀₀(200 mg·kg^-1) and Si₄₀₀(400 mg·kg^-1)treatments,respectively. The mean relative basal diameter increment under Si200 was 42.1% greater than that under Si₁₀₀(100 mg·kg^-1). ②No significant differences were observed in total biomass,organ biomass,or shoot-to-root ratio due to Si addition,although biomass distribution differed markedly among species. ③Silicon addition increased N and P concentrations in all seedling organs; however,the optimal dosage for nutrient response varied with tree life form. In conclusion,silicon fertilization significantly influences seedling growth and nutrient status in subtropical forests. The response thresholds to silicon differ among tree life forms,underscoring the importance of determining species-specific fertilization dosages.