نتایج جستجو برای: number of snags

تعداد نتایج: 21177911  

1999
KEITH A. HOBSON JIM SCHIECK

A current paradigm in conservation biology is that forest harvest practices that better approximate natural disturbance processes are more likely to conserve biodiversity. We contrasted bird communities in three replicate stands in each of 1, 13–15, and 22–28 yr old forests following wildfire and harvest in north-central Alberta, Canada. Stands were chosen from old (.120 yr) boreal mixedwood fo...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1392

تحلیل پوششی داده ها به عنوان یک علم نوپا به ابزاری برای اندازه گیری کارایی در آمده است. تحلیل پوششی داده ها به بررسی و ارزیابی واحدهای تصمیم گیرنده که یک یا چند ورودی را برای تولید یک یا چند خروجی مصرف می کنند می پردازد. از مشخصه های اصلی تحلیل پوششی داده ها حساس بودن آن نسبت به داده ها می باشد بدین معنی که عدم دقت در جمع آوری داده ها باعث به دست آمدن نتایج نادرستی می گردد. از جمله کاربردهای ان...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1389

armenias geopolitics and its historical experience have had a determining impact on the character of its foreign policy .present-day armenia is a small, landlocked country with _11,620 square miles area armenias landlocked nature makes it dependent on the benevolence of its neighbors for access to the outside world a fact that gives it a sense of isolation and vulnerability. as it was indic...

Journal: :Forests 2022

Throughout the Midwest United States, agricultural and urban development have fragmented natural areas, with a disproportionate effect on forests wetlands. The resulting habitat loss, compounded spread of white-nose syndrome (WNS), has caused precipitous population declines in several forest-obligate bat species. In 2019, we discovered remnant northern long-eared (Myotis septentrionalis Trouess...

Journal: :international journal of advanced biological and biomedical research 2014
ali salehi sardoei sadegh shahmoradzadeh fahraji hadi ghasemi

zinnia elegans, an annual flowering plant of the genus zinnia, is one of the best known zinnias. present study was conducted to evaluate the effect of different growing media on the growth and flowering of zinnia elegans. seven different growth media including coconut compost, silt, soil loam, leaf manure, (leaf manure + silt; 2:1), (coconut compost + soil loam; 1:1) and (leaf manure + soil loa...

Journal: :journal of rangeland science 2015
seyyed morteza abtahi karim bagherzadeh ehsan zandi esfahan

tragacanth gum is one of the most important medicinal and industrial productsof rangelands and is obtained from the incision of gum tragacanth-producing astragalusincluding astragalus keyserlingii. the conservation of astragalus species in rangelandshas a special place in terms of economic profit and soil conservation. the increase in priceof gum tragacanth in recent years and more attention of...

2006
Therese Johansson

Johansson, T. 2006. The conservation of saproxylic beetles in boreal forest: importance of forest management and dead wood characteristics Doctoral dissertation ISSN 1652-6880, ISBN 91-576-7115-X Forest management has altered the age structure, tree species composition and dead wood availability of Swedish boreal forests. As a consequence, many saproxylic (wood living) insect species have decre...

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