Population Characteristics of Malus sieversii in the West Part of Tianshan Mountains,Xinjiang Relationship between decline disease of exotic pines(Pinus taeda and Peliottii) and forest stand and environmental factors Stand Factors of Picea schrenkiana var. tianschanica alongthe Altitudinal Gradient in Different Longitudes Application of Fuzzy Distribution Functions to Stand Diameter Distribution of Cunninghamia lanceolata Plantations Study on the Relationship between Water Conservation Function and Stand Factors in Dawujia Watershed, Inner Mongolia Relationships of Pinus koraiensis Cone Production with Stand and Climate Factors