DISTRIBUTION OF ECTOMYCORRHIZAL FUNGI UNDER SEVERAL CHIEF FOREST TYPES IN ALPINE CONIFEROU REGION OF NORTHWESTERN YUNNAN Seedling performance of Pinus densata and its parental population in the habitat of P. tabuliformis Responses of radial growth to fire disturbance in alpine pine (Pinus densata) of different age classes in Nang County, Xizang, China Relationship between rosin output of Pinus densata and air temperature and humidity at Zhamu region of Tibet Geographic Isolation between the Homoploid Hybrid Pinus densata and Its Parental Pinus yunnanensis Population Structure and Dynamic Characteristics of Pinus densata in Southeast Tibet A Preliminary Study on Genetic Variation and Relationships of Pinus yunnanensis and Its Closely Related Species