A STUDY ON THE DIVISION OF GEOGRAPHICAL PRODUCTING AREA OF POPULUS BOLLEANA IN KASHEN DISTRICT OF XINJIANG VYGUR AUTONOMUS REGION Relationship Between Canker Outbreak and Individual Crown Structure of Populus bolleana Forest in Qingtongxia A STUDY ON NUTRIENT CONTENT AND BIOMASS OF POPULUS BOLLEANA Impacts of water stored in sapwood Populus bolleana on its sap flux Variation in Transpiration of Populus bolleana and the Influence Factors in Maowusu Sandy Area Effects of Mixed Forest of Ailanthus altissima and Populus bolleana on Host Choice of Anoplophora glabripennis Difference of Sap Flow Rate of Populus bolleana Lauche along Trunk Axial Direction