从 1 970年后 ,云南省连片华山松人工纯林内 ,陆续出现生长势衰弱 ,生长量下降 ,病虫害种类增多 ,发生频率加大 ,甚至不明原因死树的现象。随着树龄的增长 ,上述情况在面积和发生率上还有不断扩大的趋势。事实证明 ,长期以来单纯从森林病害或虫害的角度进行研究 ,虽然也取得不 From 1970 onwards, in the artificial pure forests of Pinus armandii in Yunnan Province, the phenomena of weaker growth potential, decreased growth, increased types of pests and diseases, increased frequency of occurrence, and even unexplained dead trees were observed one after another. As the tree grows, the above situation still has the trend of expanding in area and incidence. Facts have proved that for a long time simply from the perspective of forest diseases or insect pests, although also made