Abstract: The stoichiometric characteristics of plant leaves are closely linked to their physiological and ecological functions, such as photosynthesis and water-use efficiency. Among tree species within the same habitat, variations in their leaf stoichiometry reflect their distinct strategies for utilizing environmental and nutrient resources. In China’s Saihanba region, extensive plantations of Larix gmelinii var. principis-rupprechtii and Pinus sylvestris var. mongholica face challenges such as declining productivity and weakened ecosystem services, largely due to insufficient theoretical foundations in traditional nutrient management. To clarify the adaptive divergence and driving factors of the dominant afforestation species from a nutrient-use perspective and to provide scientific guidance for tree species selection and ecosystem enhancement in semi-arid regions, we conducted this study in Saihanba.

Key words: Leaf stoichiometric traits, environmental factors, Larix gmelinii var. principis-rupprechtii, Pinus sylvestris var. mongholica, semi-arid region, altitudinal gradient