نتایج جستجو برای: extent of area by forest type relative to total forest area

تعداد نتایج: 22688644  

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...

اسلامی, علیرضا, جعفری, فرهنگ, حسنی, مجید,

In the high forests which managing with close-to-nature silvicultural method, the future of forests depends on the stable establishment of saplings planted in the gaps; hence, the current study was done by selection sampling method with the aim of qualitative and quantitative investigation of natural regeneration based on the gap area in two different beech (Fagus orientalis Lipsky) forests: pu...

Journal: :محیط زیست طبیعی 0
سجاد عالی محمودی دانشجو کارشناسی ارشد جنگلداری، دانشکده منابع طبیعی، دانشگاه تهران جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران بهمن جباریان امیری استادیار گروه محیط زیست دانشکده منابع طبیعی دانشگاه تهران افشین دانه کار دانشیار گروه محیط زیست دانشکده منابع طبیعی دانشگاه تهران پدرام عطارد استادیار گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران

fire destroys major area of forests and rangelands in the world. izhe, located in khozestan province, is one of these area that was changed by this natural phenomena. the aim of this study is to determine the most important climatic factors on forest fire and its development by regression model analysis. numbers and area of the forest fire as well as weather data for a three years period (2009-...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اصفهان - دانشکده علوم 1389

this research concentrates on the lithostratigraphy, biostratigraphy, microfacies and sedimentary environment of the asmari and gachsaran formations at southwest firuzabad. the thickness of the studied section in all 608.95 meters that 220.8 meters belong to the asmari formation and 387.95 meters belong to the gachsaran formation (champe and mol members). in the study area, the asmari formation...

علی اصغر درویش صفت , , امید رفیعیان, , منوچهر نمیرانیان, ,

The aim of this study was to detect change of the forest area in the north of Iran between 1994 and 2001. The study area was covered by a 1:25000 topographic map (about 15000 ha) in Babol forests. The forest map of 1994 was extracted from 1:25000 topographic digital map. Landsat 7 ETM+ image dated July 30, 2001 was analyzed to produce the forest map for the end of the period. Since the evaluati...

ژورنال: علوم آب و خاک 2006
علی اصغر درویش صفت , , امید رفیعیان, , منوچهر نمیرانیان, ,

The aim of this study was to detect change of the forest area in the north of Iran between 1994 and 2001. The study area was covered by a 1:25000 topographic map (about 15000 ha) in Babol forests. The forest map of 1994 was extracted from 1:25000 topographic digital map. Landsat 7 ETM+ image dated July 30, 2001 was analyzed to produce the forest map for the end of the period. Since the evaluati...

Azadnejad , Saeed , Taefi Feijani , Masoud ,

Mapping of forest extent is a prerequisite to acquire quantitative and qualitative information about forests and to formulate management and conservation strategies. forest canopy density (FCD) model is one of the useful RS methods for forest mapping using satellite images. One of the most serious challenges in FCD model is the weakness in the calculation of canopy density in low density forest...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده زیست شناسی 1388

126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده برق و کامپیوتر 1391

in the area of automotive engineering there is a tendency to more electrification of power train. in this work control of an induction machine for the application of electric vehicle is investigated. through the changing operating point of the machine, adapting the rotor magnetization current seems to be useful to increase the machines efficiency. in the literature there are many approaches wh...

2014
Anne Sverdrup-Thygeson Gunnhild Søgaard Graciela M. Rusch David N. Barton

In order to safeguard biodiversity in forest we need to know how forest policy instruments work. Here we use a nationwide network of 9400 plots in productive forest to analyze to what extent large-scale policy instruments, individually and together, target forest of high conservation value in Norway. We studied both instruments working through direct regulation; Strict Protection and Landscape ...

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