Stoichiometric Characteristics of Pinus armandii and Quercus aliena var. acuteserrata Stands in the Qinling Mountains

To understand how species and stand age affects stoichiometric characteristics of plant leaves, litter andsoil, and the limiting status of N, P nutrients, Pinus armandi and Quercus aliena var. acuteserrata natural forests with 4 stand age groups located in the Qinling Mountains, were selected to test C, N and P stoichiometric characteristics. The results showed that the C, N and P concentrations in each age group of 2 forests were the highest in tree leaves and the lowest in soil. The C concentration in P.armandi leaves was higher than that in Q.aliena var. acuteserrata, while N and P concentrations were lower. Species have extremely significant effects on the stoichiometric characteristics of plant leaves, C content, N content, C : N and C : P of litters and P content and N : P in the soil. Stand age significantly effected on C content of leaves and litters. Also, it has extremely significant affect on P content, C : P, N : P ratio in the soil. The N : P ranges from 7.47 to 12.50, and the N played the dominant role in normal growth of plants.