论文部分内容阅读
1建立固定标准地调查发生初期虫口密度1.1设立固定标准地早春在3月下旬选择落叶松纯林,林龄20—30年之间具有代表性做标准地,方法在所选地内做长方形标准地,标准地内落叶松株数要超过200株,标准地面积根据达到株数而定。标准地四角设标桩,边线有标志,四角标桩,标明方位角、距离,然后将标准地内落叶松依次编号,用铅油在视线高度写在树干上。写好以后再任选25株标准木为标准株,记好标准株编号,并把标准株在胸高位置缠上两道塑料环,塑料环宽10厘米,两环间距离10厘米。
1 establish a fixed standard to investigate the occurrence of early insect population density 1.1 set a fixed standard Early spring in late March to select pure larch forest, aged 20-30 years to do a representative standard between the method to do the selected rectangle , The standard number of larch plants to more than 200, the standard area according to reach the number of plants may be. The standard four corners of the standard pile, the edge of a sign, four corners of the pile, indicating the azimuth, distance, and then the standard number of larches in turn, with lead oil in sight height written in the trunk. Written after the election of 25 standard wood as a standard strain, remember the standard strain number, and the standard strain in the chest high position wrapped around two plastic rings, plastic ring width of 10 cm, the distance between the two rings 10 cm.