论文部分内容阅读
落叶松尺蛾Erαnnis αnkerαriα Steudinger是落叶松的重要食叶害虫,近几年在丰宁县北部落叶松人工林中大发生,虫口密度很大。5月下旬开始为害,到6月下旬往往把针叶食光,被害林分一片枯黄,如同火烧一般。7月下旬以后,被害林木又能发芽长叶,叶片黄嫩瘦弱。 为了搞清落叶松尺蛾为害对落叶松立木生长的影响,我们于1986年,对尺蛾的发生、为害情况进行了观察和树木解析。在观察样地内随机抽取15株活立木,测取害虫发生前四年和为害期间的胸径、树高、材积连年生长量,推算该虫害对林木胸径、树高、材积连年生长量
Larvae Larvae Erαnnis αnkerαriα Steudinger is an important leaf-eating pest of larch. In recent years, it has occurred in Larix gmelinii plantation in Fengning County, with a large population density. In late May began to harm, to the late June tend to light the leaves, the forest was a piece of yellow, as fire burning in general. After late July, the trees and leaves of the victims can sprout long leaves, yellow leaves thin and thin. In order to understand the larch moth damage on the growth of larch stand legislation, we in 1986, on the moth occurrence, damage were observed and tree analysis. Fifteen live standing woods were randomly selected in the observation plots. The DBH, tree height and volume annual growth of the pests were measured. The DBH, tree height,