Abstract: Litter plays an important role in regulating the nutrient cycle between plants and soil, and maintaining C, N, and P balances in forest ecosystems. This research aimed to clarify the nutrient content of litter from various sources and the environmental factors influencing the different nutrient content in litter under different forest types (coniferous forest and broadleaf forest) in forest ecosystems in Qinghai Province. This study examined coniferous forest and broadleaf forest litter samples from 21 counties in Qinghai Province, and explored the changes in litter C, N, P stoichiometric characteristics in different forest types with altitudes, as well as the influencing factors. It was found that: 1) The contents of litter C and N, the ratio of C∶P and N∶P in the coniferous forests were higher than that in the broadleaf forests, while the litter P content was lower, across the altitude gradient; 2) The content of litter N, the ratio of C∶P and N∶P in the coniferous forests increased linearly with increasing altitude, while the litter P content and the ratio of C∶N decreased with altitude; 3) For both the coniferous and broadleaf forests, significant correlations were found among plant factors (litter biomass, nutrient content and the C, N, P stoichiometric characteristics) and longitude, latitude, gradient, canopy density, plant community height, shadow area (except the litter P content and the C∶P ratio in the broadleaf forests); 4) The above results showed that the litter C, N, and P contents were generally low in the coniferous and broadleaf forests, which were limited by the N content (N∶P<14). Meanwhile in the high-altitude areas the coniferous forests were also limited by P content (14<N∶P<16); 5) Environmental factors (latitude, altitude, gradient, etc.) directly affected the litter biomass, nutrient content and ecological stoichiometric characteristics. In summary, the nutrient content of litter is affected by the forest type, resulting in significant differences in ecological stoichiometry. At the same time, geographic factors (latitude, altitude, slope, among others) were also significantly correlated with nutrient content. Therefore, the changes in litter stoichiometry and factors affecting those changes should be taken into consideration in order to formulate ecologically sound forest management and utilization measures.

Key words: litter, ecological stoichiometry characteristics, nutrient, forest type, altitude