Comparison of Natural Regeneration for Three Different Conifer Species on Zhanggutai Sandyland

Comparative experiments of natural regeneration for Pinus sylvestris var.mongolica,Pinus densiflora Sieb et Zucc.and Pinus tabulaeformis exist on Zhanggutai's sandyland in Zhangwu county of Liaoning province were conducted.Natural regeneration intensity of one-year-old three conifer species are separately 3 594-5 133,20 300-50 000 8 300-13 900 plants·hm-2;the intensity of natural regeneration of Pinus densiflora Sieb et Zucc.is optimal than that of Pinus tabulaeformis;the intensity of natural regeneration of Pinus tabulaeformis is optimal than that of Pinus sylvestris var.mongolica;natural regeneration of one-year-old Pinus sylvestris var.mongolica seedlings are difficult to live through winter.Survival rate of seedlings should increase by 66% after covering.One-year-old seedlings of Pinus densiflora Sieb et Zucc. Pinus tabulaeformis whose overwintering survival rate are 17.20% 20%,respectively,are relatively easy to live through winter;survival rate of seedlings are 54.94% 51.28% after covering.Therefore,artificial measures should be taken to promote the natural regeneration of Pinus sylvestris var.mongolica,Pinus densiflora Sieb et Zucc.,Pinus tabulaeformis.