该研究的目的是寻找松枝枯病在大连市经常发生的原因。选择松树枝枯病Cenangiumferruginosum不同发病程度的三块林分 :无病林 ,轻病林和重病林 ,分别测定其中不同年龄枝的相对含水量 ,并通过对松树枝枯病枯死枝条上子实体着生部位调查证明 ,在黑松的生长季节 ,相对含水量低的林分和相对含水量低的 3龄枝上枝枯病发病率高。从林分、树体和枝条的相对含水量测定 ,都证明水分亏缺是诱导松树枝枯病发生的重要原因之一 The purpose of this study is to find out why pine wilt occurs frequently in Dalian. Cenangiumferruginosum was selected to determine the relative water content of the branches of different ages at different stages of disease-free, light-disease and severe-disease. Health survey showed that in the growing season of Pinus thunbergii, the relatively low water content of the forest and the relative low water content of 3 branches of the high incidence of branch blight. From the stand, tree and branches of the relative water content determination, have proved that water deficit is one of the important reasons for the induction of pine shoot blight