Study on Community Stucture and Species Diversity of Picea asperata Plantations at Different Altitudes

In this paper, the community stucture and species diversity of Picea asperata plantations at different altitudes in Jiuzhaigou county were studied by the field experiment method. The results showed that: (1) the species composition of the arbor layer of Picea asperata plantation was relatively single, and the understory was mainly dominated by Asteraceae, Ranunculaceae, Rosaceae, Lamiaceae and Apiaceae. The species richness was generally represented as herb layer > shrub layer > tree layer. Lonicera szechuanica and Rubus coreanus had great regeneration potential in shrub layer. Thalictrum aquilegifolium was a good companion grass species in the herb layer, and the higher the altitude, the more obvious of the advantage. (2) with the increase of altitude, the growth rate of Picea asperata significantly decreased. The average tree height of Picea asperata at low altitude (2500 m) was about three times higher than that at high altitude (3000 m). (3) at low altitude, the crown density of Picea asperata stands was as high as 0.9, and the coverage of shrub and grass was extremely low. At high altitude, the crown density was lower, but the coverage of understory shrub and grass, species richness and diversity were higher.