نتایج جستجو برای: forest

تعداد نتایج: 106136  

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...

Journal: :محیط شناسی 0
حسن دارابی استادیار گروه مهندسی طراحی محیط، دانشکدة محیط زیست، دانشگاه تهران ایمان سعیدی مربی گروه مهندسی فضای سبز، دانشگاه ملایر

introduction urban landscape is experiencing rapid changes which put all urban domains under pressures. these processes revolutionize urban landscape into spaces without ecologic values. the sustainability of green patches and corridors has been scathed by lack of ecological approaches in planning and design. therefore, urban green spaces structures and functions have been damaged. green spaces...

Journal: :محیط شناسی 0
علی جعفری استادیار گروه علوم جنگل دانشکدۀ منابع طبیعی دانشگاه شهرکرد زهرا آرمان دانشجوی کارشناسی ارشد جنگل داری، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی سلطانی استادیار گروه علوم جنگل، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی لطفی هیات علمی دانشگاه صنعتی اصفهان

introduction forest ecosystems have continuously downgraded due to every environmental pressure including climate change, aerosols deposits, industrial pollutions and other degradation factors. the output soon or late would be a different forest. forest monitoring is a well-regulated and usually long running procedure, which has the ability to detect these phenomena and reactions based on aims ...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

the ecological potential assessment of forest sites introduces an index or indices that show the potential of forest site for fulfillment of special different roles of forest. khanikan forest at chalous needs precise investigation for assessment as indicator of lowland forests in forest ecosystems of northern iranwith considering its location position in caspian lowland and different values. th...

Journal: :journal of sciences, islamic republic of iran 2010
m. sabbaghan

a 1993 result of j. llibre, and m. misiurewicz, (theorem a [5]), states that if a continuous map f of a graph into itself has an s-horseshoe, then the topological entropy of f is greater than or equal to logs, that is h( f ) ? logs. also a 1980 result of l.s. block, j. guckenheimer, m. misiurewicz and l.s. young (lemma 1.5 [3]) states that if g is an a-graph of f then h(g) ? h( f ). in this pap...

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...

Information on the productivity, costs and applications of the logging system is a key component in the evaluation of management plans for the rehabilitation and utilization of Caspian forests. Skidding and road construction costs are expensive forest operations. Determining the optimum forest road network density is one of the most important factors in sustainable forest management. Logging me...

Esmaiel Khosropour Kamran Pourmoghadam Kimia Pourmoghadam, Maziar Haidari,

Physiological factors have effects on most forest parameters such as forest classification so that understanding knowledge about this subject is important to manage forests. The forests of Sorkhake-sanjabi village with area of 1645 ha located in Eslam Abad city, Kermanshah province, Iran were selected. 23 sample plots with rectangular shape (40m*50m) were selected and the species, origin of spe...

Journal: :جغرافیا و توسعه ناحیه ای 0
ولایتی ولایتی کدیور کدیور

the growth of industries during the industrialization and after the industrial revolution has caused environmental problems all around the world; specifically in industrial countries. in spite of having high technology, industrial countries have not been able to solve the problem of environmental pollution. even meetings and conferences such as those held in stockholm and johannesburg have not ...

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