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杨树蛀干害虫 (黄斑星天牛与光肩星天牛 )在林间水平格局为聚集型分布 ;垂直方向用 Weibull分布拟合。平均虫口密度与杨树树干的高度与直径都有密切的关系 ,其与树干高度的关系可用 y=3.481 5 + 0 .5 30 5 x - 0 .0 85 4x2表示 ,危害最严重部位在3.1 0 6 7m高处 ;其与树干直径的关系可用 y=- 4 .7896 + 1 .0 5 37x - 0 .0 36 9x2表示
Poplar borers pests (Phasianus colchicus and Anoplophora glabripennis) were clustered in the forest level, and fitted with Weibull distribution in the vertical direction. The average density of poplar trunks is closely related to the height and diameter of poplar trunks. The relationship between height and trunk height can be expressed as y = 3.481 5 +0 .5 30 5 x - 0 .0 85 4x2. The most serious part is 3.1 0 6 7m height; its relationship with the diameter of the trunk available y = - 4 .7896 + 1 .0 5 37x - 0 .0 36 9x2 said