نتایج جستجو برای: forest trees

تعداد نتایج: 184211  

Oak decline is an eminent factor, which has a significant role in degradation and change in Zagros forests. The goal of present study was to assess the crown surface area of oak trees in Sarableh forests, Ilam province. For this purpose, permanent sample plots were used. Eighty sample plots with 10 Ar area were applied based on systematic-random method in a 150×200 survey network in 120 ha. The...

Pistachio trees (Pistacia) play combined roles in ecotourism, conservation of soil and water, flood control, forage production for domestic and wild animals and resin and seed production in arid and semi-arid areas. It is very important to protect this species but, in recent decades, several factors have caused damaged to these trees. One of the most important factors of Pistacia forest destruc...

Journal: :جنگل و فرآورده های چوب 0
سمیرا ساسانی فر دانشگاه ارومیه منوچهر نمیرانیان دانشگاه تهران نصرت الله ضرغام دانشگاه تهران

knowing and conducting studies on size characters of trees is essential for assessing the tree volumeand/or other statistical parameters and also forest management. the characteristics of 529 treesincluding diameter at breast height (dbh) and total height were measured in an even-aged fraxinusstand for two periods from 2005 to 2012 in chelir district, a part of experimental kheyrud forest.resul...

Journal: :محیط شناسی 0
داود کرتولی نژاد سید محسن حسینی سید خلاق میر نیا

the damages due to dwarf mistletoes to the industrial forests encouraged the scientists to evaluate the infection intensity and illustrate the spatial distribution of mistletoes for forest management, wild life and biodiversity conservation. there are two current systems to evaluate infection intensity wich are easier, cheaper, more efficient and authoritative than others in all over the world,...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

different ecologic factors influence on forming, development and sustaining of the plant communities, among which physiographic variables are the most important ones. the aim of this study was to identify forest types and effect of physiographical factors such as sea level height, slope and aspect of the site on quantitative characteristics of forest types in 2nd district of vaz forest with are...

سعیدی , زریر , سلطانی, علی, شریعتی نجف آبادی, حسین, گرجستانی‌زاده, شادی,

Forest trees demonstrate different distribution patterns, depend on their living condition (Such as pest infestations). Forest density and epidemic pest concentration are hypothetically among the most influential factors. The current study was carried out on distribution pattern of the orchard ermine (Yponomeuta padella) infested hawthorn trees (Crataegus monogyna) in Bazoft river watershed in ...

Journal: :نامه انجمن حشره شناسی ایران 0
مصطفی نیکدل اریش دایلر

during the study of natural enemies of insect pests of forest trees and shrubs in arasbaran forest of iranian province of east azarbaijan, a number of larvae of yponomeuta evonymella l. were collected on wild cherry trees. the specimens were reared in the laboratory, where parasitoid wasps of the family ichneumonidae emerged and later identified as agrypon canaliculatum (ratzeburg, 1844). the i...

Journal: :caspian journal of environmental sciences 2010
m. nikooy

in the shafaroud forest, logging operation is generally performed by using selective cutting methods. chainsaw and cable skidder are two main forest machines for harvesting of this forest. however, forest harvesting operations result in serious residual stand damage during felling, winching and skidding operations in this forest. residual stand damage resulting from selective cutting was assess...

Journal: :جنگل و فرآورده های چوب 0
وحید اعتماد استادیار گروه جنگلداری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران مرتضی مریدی دانشجوی کارشناسی ارشددانشگاه تهران کیومرث سفیدی استادیار دانشکده فناوری کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی

evaluating the forest stands structure in different development stages is one of the ways for better understanding the forest dynamics and its response to natural disturbances. this study was carried out in the compartment 319, kheiroud forest in order to quantify the structure properties of mixed beech stands in the stem exclusion phase. for this purpose, three one-hectare sample plots were se...

Journal: :environmental resources research 2014
mojtaba amiri ramin rahmani khosro sagheb-talebi hashem habashi

investigation on structure and dynamics of natural forest ecosystems is an important issue for silvicultural decisions. the aim of this study is to analysis dynamics and structure of a beech stand during 5-year period in the shast kalateh forest in the caspian region, north of iran. data were collected from a 16.9ha permanent research plot established in a natural unlogged stand in 2006. all li...

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