Document Type : Research Paper
Authors
1
Ph.D Student of Silviculture and Forest Ecology, Faculty of Natural Resources, University of Tehran, I. R. Iran
2
Associate Prof., Faculty of Natural Resources, University of Tehran, I. R. Iran
3
Prof., Biological Control Research Department, Iranian Research Institute of Plant Protection, Agricultural Research,
4
Associate Prof., Faculty of Agricultural, University of Tehran, I. R. Iran
5
Assistant Prof., Insect Taxonomy Research Department, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), I. R. Iran
6
Ph.D Student of Silviculture and Forest Ecology, Moscow Forest State University, Moscow, Russia
Abstract
In order to study the beech scale and some of the effective environmental factors on beech scale density on eastern beech trees, after field inspection, 10 hectare of infected beech stands were specified in low-, mid- and high lands of Kheyrud forest. At each studied area, 12 scale infected beech stands were randomly determined and their characteristics were recorded in special papers. Effect of bark roughness and direction of trunk of beech trees and height from the ground on beech scale density and period of infestation in three studied areas were investigated by using non-parametric Kruskal-Wallis and Friedman tests. Completely rough barks having deep cracks were assigned highest density of beech scale by 5.5 average. Beech scale density at north and east sides of trunk was significantly more than south and west sides. Also, density of this scale at 2.5 m height of trunk was the greatest by 4.4 average. With increasing elevation from sea level, infected stands initially increased from 23.8 to 28.3 percent and then decreased to 15.4 percent. Beech scale density was most in high land by 30 percent high density and also beech trees infection length was highest in middle land and high land by 5.35 and 7.5 m, respectively diameter class 40-60 cm was recognized as the best diameter for colony formation of beech scale by 36 percentage infection frequency and 38 percentage high density.
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