نتایج جستجو برای: mixed and natural stands

تعداد نتایج: 16917246  

2006
M. M. Amoroso E. C. Turnblom

We studied pure and 50/50 mixtures of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) plantations to compare attained total yields between mixed-species stands as opposed to monocultures of equal densities. Whether overall stand density influences this outcome has not been adequately investigated, and to address this we included three den...

2013
Qing Zhao Ermias T. Azeria Mélanie-Louise Le Blanc Jérôme Lemaître Daniel Fortin

Ecosystem-based forest management strives to develop silvicultural practices that best emulate natural disturbances such as wildfire to conserve biodiversity representative of natural forest ecosystems. Yet, current logging practices alter forest structure and reduce the proportion of old-growth forest and, consequently, can exert long-term effects on the dynamics of forest biota. The stand- an...

2014
Xitian Yang Dongfeng Yan Canran Liu Lalit Kumar

Natural regeneration is the natural process by which plants replace themselves. It is a cost-effective way to re-establish vegetation, and it helps to preserve genetic identity and diversity. In this study, we investigated the natural regeneration of trees in three types of afforested stands in the Taihang Mountains, China, which were dominated by Robinia pseudoacacia (black locust), Quercus va...

Journal: :Fungal Biology 2021

Soil sampling is a critical step affecting perceived fungal diversity, however optimization for high-throughput-DNA sequencing studies have never been tested in Mediterranean forest ecosystems. We identified the minimum number of pooled samples needed to obtain reliable description communities terms diversity and composition three different forests (pine, oak, mixed-pine-oak). Twenty soil were ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهرکرد - دانشکده ادبیات و علوم انسانی 1389

current studies in second language (l2) learning have revealed the positive role of corrective feedback (cf) in both oral and written forms in different language features. the present study was an attempt to investigate the effect of both direct and indirect written corrective feedback (wcf) on the use of grammatical collocations in l2 writing. the study also sought to examine whether the effec...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده مهندسی علوم آب 1393

drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...

Journal: :ecopersia 2015
einollah rouhi-moghaddam ebrahim sargazy ahmad gholamalizadeh

the purpose of the present research was to study the properties of natural habitats and growth status of the genus tamarix in miankangi, sistan province, south-eastern iran. selective sampling was used to examine the natural stands structure. then, the one ha-rectangular sample plots were stablished in the stands and surrounding bare lands as control plots. quantitative variables of stands viz....

Journal: :جنگل و فرآورده های چوب 0
محمود بیات دکتری جنگل داری، دانشکدۀ منابع طبیعی دانشگاه تهران، کرج، ایران منوچهر نمیرانیان استاد، دانشکدۀ منابع طبیعی دانشگاه تهران، کرج، ایران محمود زبیری استاد، دانشکدۀ منابع طبیعی دانشگاه تهران، کرج، ایران تیمو پوکالا استاد گروه جنگل داری، دانشگاه شرقی فنلاند، جوئنزو، فنلاند

hyrcanian forests are the most valuable forests in the north of iran and industrial harvesting occurs only in this area. it is a productive region near the southern coast of caspian sea. in these forests mixed beech stands mostly shown uneven-aged structure that is managed under selection system. in order to determine the priority of uneven aged method not only from an ecological view, but also...

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