Objective To understand the C, N, P stoichiometric ratio pattern of the components in the understory vegetation layer and litter layer of the typical forest ecosystem in Mopan Mountain area, and to observe the influence of tree species and organs on the C, N, P stoichiometric characteristics of the understory vegetation layer and litter layer, so as to provide reference for nutrient redistribution in the forest ecosystem.

Method Five typical forests were studied in subalpine forest in central Yunnan, the samples of understory vegetation and litters from different forests were collected in the field. The stoichiometric characteristics of C, N, and P in different organs of understory vegetation layer and components of litters layer were measured.

Result The results showed that the C contents in the understory vegetation layers (shrub leaves, stems and roots, above-ground and underground parts of herbs) and litter layers (undecomposed layer, semi-decomposed layer, fully decomposed layer) of the five forest types were 410.17-561.08 and 81.47-625.8 mg·g⁻¹, the N contents were 3.07-15.89 and 9.87-17.5 mg·g⁻¹, and the P contents were 0.35-0.9 and 0.37-0.93 mg·g⁻¹. In different organs and decomposition levels, the C, N, and P contents of the shrub layer ranked as leaf > root > stem, and the C and P contents of the herb layer ranked as aboveground > underground part, while and the N content was the opposite; N and P content of the litter layers ranked as completely decomposed layer > semi-decomposed layer > undecomposed layer, and the C content was the opposite.

Conclusion The growth of the understory vegetation layer of the five forest types in subalpine forest in central Yunnan is relatively slow, limited by both nitrogen and phosphorus. The decomposition rate of litters is slower, and the nutrient cycling capacity is low. Therefore, it is considered that appropriate protection of understory vegetation layer will improve the soil fertility and maintain long-term stable productivity of stand.