نتایج جستجو برای: tree density

تعداد نتایج: 573480  

Gaps created by falling trees (tree-fall gaps) are a natural disturbance in forest ecosystems. Understanding scale, pattern and the effect of gaps on regeneration is important to current and future forest management. The aim of this study was to determine the size, shape and the spatial pattern of tree-fall gaps and of associated regeneration. This study was carried out in three parcels (No.15,...

Journal: :جنگل و فرآورده های چوب 0
ابراهیم لشکربلوکی دانشجوی دکتری تخصصی، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران کامبیز پورطهماسی استاد، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران رضا اولادی استادیار، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران محسن کلاگری استادیار، مؤسسة تحقیقات جنگل ها و مراتع کشور، تهران، ایران

wood farming and especially poplar plantation is a key answer to the increasing demand of raw materials in wood and cellulosic industries. according to the diversity of wood applications, taking into account the wood quality and grading by wood farmers/buyers as well as its quantity can lead to an optimal management of production and consumption. in this regard, it is necessary to introduce and...

Journal: :مرتع و آبخیزداری 0
محرم اشرف زاده دانشجوی کارشناسی ارشد رشتة مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس رضا عرفانزاده استادیار گروه مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس

this study was carried out to investigate the effect of crown canopy of ziziphus spina-christi on seed bank characteristics (density and similarity with above ground flora) in two sites with saline-alkaline and alkaline soils. in each soil, forty plots were established, half in and half outside of z. spina-christi cover. in each plot, soil sampling was done from 0-5 and 5-10 cm depths. paired a...

Journal: :Journal of Physics Communications 2018

ژورنال: علوم آب و خاک 2002
علیرضا هادیان, , حسین سیدالاسلامی, , عبدالمجید رضایی, ,

Color sticky board traps are used in pest management for capture of adult insect, to estimate and predict population densities in later stages. Yellow sticky board traps showed high attraction for pistachio psylla. It is important to study these relationships for the right placement of traps. For each of three repetition in one year, four pistachio trees were selected randomly in one orchard. E...

علیرضا هادیان, , حسین سیدالاسلامی, , عبدالمجید رضایی, ,

Color sticky board traps are used in pest management for capture of adult insect, to estimate and predict population densities in later stages. Yellow sticky board traps showed high attraction for pistachio psylla. It is important to study these relationships for the right placement of traps. For each of three repetition in one year, four pistachio trees were selected randomly in one orchard. E...

     This current research was investigated the long – term effects of fire on vegetation and regeneration of beech (Fagus orientalis L.) in the mountain forest in Lesakoti forests in Tonekabon city in north of Iran. In both of burnt and unburnt areas, 30 plots 1000m2 and in total 60 sampling plots were identified using random-systematic 100 m × 150 m grid and density and DBH of trees and densi...

2007
Werner Stuetzle Rebecca Nugent

The goal of clustering is to detect the presence of distinct groups in a data set and assign group labels to the observations. Nonparametric clustering is based on the premise that the observations may be regarded as a sample from some underlying density in feature space and that groups correspond to modes of this density. The goal then is to find the modes and assign each observation to the do...

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