The Occurrence of Shoot Dieback of Exotic Pines in Relation to Stand Growth and Site Conditions

Dinerent tree species,parent rock,soil,stand age,and snow injury are thefive factors that affect the occurrence rate of shoot dieback of exotic pines.The degree ofinfluence of these factors in terms of partial correlation coefficients follows the descending sequence respectively,Tree species,parent rock,soil,stand age and planting quality compre-hensively affect the damage degree of the shoot dieback in terms of partial correlation coefficients being in the descending sequence respectively The composite correlation coefficient ofeach factor with the occurrence rate is 0.838 209 8.The composite correlation coefficient ofeach factor with the severity degree is 0.8687435.