A STUDY ON LONG TERM SOIL EROSION MONITORING IN NEWLY ESTABLISHED HIGH-YIELDING TIMBER PLANTATIONS OF MAIN SPECIES IN CHINA A COMPREHENSIVE ANALYSIS ON FIXED FOREST PEST AND DISEASES, MONITORING FINDINGS IN NEWLY ESTABLISHED HIGH-YIELDING TIMBER PLANATATIONS OF MAIN SPECIES A STUDY ON LONGTERM SOIL FERTILITY MONITORING FINDINGS IN NEWLY ESTABLISHED HIGHYIELD TIMBER PLANTATIONS OF MAIN SPECIES