Abstract: The vegetation composition and diversity in the process of natural restoration on the clear-cutting forestland of Pinus sylvestris var. mongolica plantations in Zhanggutai district of Liaoning Province were studied by sampling method. The results showed that in the naturally restored plant communities, there were 49 species, belonging to 26 families, and the composite family and grass family took up the most part of the whole. As for the one-year, two-year, three-year and five-year clear-cutting forestlands, the Simpson diversity index of plant communities was 0.681, 0.792, 0.845 and 0.870, respectively, and the Shannon-Wiener index and Pielou index had the similar changing trend as the Simpson index. The total biomass of the naturally restored vegetation increased from 1.351 t·hm^-2 in the first year to 9.745 t·hm^-2 in the fifth year. Litter production started from the second year, and increased from 0.824 t·hm^-2 to 1.403 t·hm^-2 after 5 years. The contents of organic matter, N, P and K in 0-15 cm soil layer increased markedly, in comparing with those prior to clear-cutting. Fallowing played an important role in the early litter production and nutrients accumulation on sandy land.

Key words: Land use change, Sediment production, Loss Plateau