Ecological stoichiometry characteristics of the leaf–litter–soil continuum of Quercus acutissima Carr. and Pinus densiflora Sieb. in Northern China

To research the nutrient circulation laws of the pine-oak forest ecosystem, this paper studied the ecological stoichiometry characteristics of organic carbon (C), total nitrogen (N) and total phosphorus (P) in the two "leaf–litter–soil" continuums (QAC: Quercus acutissima Carr., PDS: Pinus densiflora Sieb.) in China and their intrinsic relationships. Results showed that (1) Contents of C, N and P in the two continuums were C > N > P, and total contents of the different components were leaf > litter > soil. (2) Ecological stoichiometry characteristics of C, N and P in the two continuums were C:P > C:N > N:P. For the different components, the C:N and C:P were litter > leaf > soil, and the N:P was leaf > litter > soil. (3) Content of C in leaves was higher than that of the global and Chinese values and indicated that their defense capabilities against outside environmental forces were very strong. While contents of N and P in soil were lower than that of the global and Chinese values. Therefore, attention should be paid to selecting nitrogen fixing species and strengthening the construction of a mixed forest in mountainous area of northern China and similar areas around the world.