PHENOTYPIC DIVERSITY IN NATURAL POPULATIONS OF PICEA BALFOURIANA IN SICHUAN, CHINA Studies on root biomass and productivity in dominant plantation populations in the mountainous land in western Scihuan Macronutrients and their allocations in non-photosynthetic organs in the Picea balfouriana in western Sichuan CONCENTRATION,STORAGE AND ALLOCATION OF NUTRIENT ELEMENT IN PICEA BALFOURIANA PLANTATION OF WEST SICHUAN