Multivariate Analysis of the Ecological Factors and the Modular Structure of Gordonia acumenata Young Tree Population in Mountain Jinyun, Sichuan, China Analysis of the Relatedness of Dominant Populations and Ecological Factors in the Secondary Succession Forest Communities of Jinyun Mountain EFFECT OF SEEDLING DISK HEIGHT AND SEEDLING DENSITY ON TOBACCO SEEDLINGS GROWTH Discussion about research mode of Chinese materia medica based on grey system theory combined with multivariate analysis method