نتایج جستجو برای: forest structure

تعداد نتایج: 1663160  

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: :محیط زیست طبیعی 0
زهرا نوری دانش آموختۀ دکتری جنگل داری، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران محمود زبیری استاد گروه جنگل داری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگل داری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران محمدرضا مروی مهاجر استاد گروه جنگل داری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران

beech forests in midland areas of hyrcanian forests of iran are the most important forests having the highest degree of naturalness. these forests are the valuable source of wood production and other forest products. one of the most important characteristics of plant communities is the spatial pattern of trees. ecological process in forest ecosystems are directly influenced by the spatial patte...

نادری, مصطفی, جعفرزاده, علی‌اکبر , حیدری, مهدی, کریمی‌کیا, حمدیه,

The key factor in understanding the forest ecosystems is forest structure. Spatial arrangement and location of trees are both one of the main components of forest stand structure. This study was carried out in Manesht protected area, Ilam province. In order to determine the ecological groups and spatial patterns of indicator species, we used fixed-area plots method. For data collection, 125 squ...

A. Amirteimoori J. Malaei Boosari S. Mohammadi Limaei

The aim of this research was to measure the relative efficiency of forest management plans in north of Iran. In order to fulfill the research, data of 12 forest management plans were collected from the financial balance sheets of Shafaroud Forest Company during a ten years period. First of all, basic Data Envelopment Analysis (DEA) models (BCC and CCR) were used to determine the efficiency. The...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده جنگلداری و مهندسی چوب و کاغذ 1386

چکیده ندارد.

Abstract Todaychr('39')s forest structure issue has converted to one of the main ecological debates in forest science. Determination of forest structure characteristics is necessary to investigate stands changing process, for silviculture interventions and revival operations planning. In order to investigate structure of the part of Ghale-Gol forests in Khorramabad, a set of indices such as Cla...

In large regions of the world, biomass is a very important source of energy. The global bioenergy market based on forest biomass is growing rapidly. About 92 % of the bioenergy in Sweden comes from forests. Biomass from forests is not homogenous. The locations, transport distances, and transport methods, can differ very much and the industries that need biomass as input prefer raw materials wit...

Journal: :جنگل و فرآورده های چوب 0
فریده امیدوار حسینی دانشجوی کارشناسی ارشد رشتۀ جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، تهران، ایران رضا اخوان استادیار پژوهش، مؤسسۀ تحقیقات جنگل ها و مراتع کشور، تهران، ایران هادی کیادلیری استادیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران اسداله متاجی دانشیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران

one of the most visible aspects of a forest stand structure is the spatial patterns of trees. competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. for this purpose, an unmanaged intact forest was selected with 26 hectares area. all chestnut leaf oak (quercus castaneifolia) trees with a ...

Journal: :caspian journal of environmental sciences 2007
m. tabari

composition and structure of a three-storied fagus orientalis-dominated forest was investigated in the caspian forests, north of iran. circular sampling plots of 1000 m2 occupied by advance growth and natural regeneration were randomly chosen where the initial cuttings (with shelterwood aim) were performed. abundance of species at different growth stages and quality of seedlings and saplings we...

Leaf size indices of the tree species in the peatland of Agusan del Sur in Mindanao in Philippines was examined to deduce the variation of forest structure and observed forest zonation.  Using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined.  The species includes Ternstroemia phi...

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