تحليلي بر سه خشكيدگي زربين در جنگلكاري التپه (بهشهر)

Assimilation on cypress (Cupressussem peruirens var. horizentalis) death in the forestation of Behshar area.

During the recent years there were some reports about the death of cypress (C.sempervirens var.horizentalis) on various forestation in Mazandaran province . For this study the Altappeh area was choosen. The Ratio Estimation method was used on randomized systematic design in strips with of 10 meter and intervals 200 meter each other for selection of trees (statical severitg was 3%). The culture of infested pices on PDA the pestalotiopsis sp was isolated, pathogenicity of this fungus has been done on vase and nerseries seedlings. The resualt showed infestation severity on Altappeh area was % 4.17 and distrubiution of diameter and hight of infested trees showed same age curve. Percentage of destructive in different parts of trunk showed the death in 13 of the top of trees were maximum. It is showing this disease have propagated the later years. Management on this forstation should be on base of cutting and exitting infested trees and guidance the competation between the native trees and., (C.sempervirens var.horizontalis) in oder to stablishment of mixture forests of native hard woods and conifer(cypress).