نتایج جستجو برای: and forest
تعداد نتایج: 16850233 فیلتر نتایج به سال:
Extended abstract 1- Introduction Changing the forests and pasture landuses to agricultural lands is one of the major global concerns about environmental degradation and climate change. As a result of the rangeland and forest changes into agricultural land and also tillage operations, about 430 million hectares, representing 30% of the world's total plowed land, are annually eroded and leavin...
the damages due to dwarf mistletoes to the industrial forests encouraged the scientists to evaluate the infection intensity and illustrate the spatial distribution of mistletoes for forest management, wild life and biodiversity conservation. there are two current systems to evaluate infection intensity wich are easier, cheaper, more efficient and authoritative than others in all over the world,...
روابط بین مراحل زندگی (لاروی، گذر و بلوغ) شانه دار mnemiopsis leidyi و شاخصه های فیزیکوشیمیایی و زیستی با استفاده از مدل های مختلف بر اساس تغییرات زمانی (ماه) و مکانی (ترانسکت، ایستگاه و لایه) در امتداد سواحل مازندران طی سال 1391 ارزیابی شد. به منظور بالا بردن عملکرد مدل ها، از گونه های غالب پلانکتونی در هر فصل (90% تراکم کل) برای مدل سازی استفاده گردید. برای درک بهتر از وضعیت اکولوژیکی شانه ...
one of the most visible aspects of a forest stand structure is the spatial patterns of trees. competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. for this purpose, an unmanaged intact forest was selected with 26 hectares area. all chestnut leaf oak (quercus castaneifolia) trees with a ...
leaf size indices of the tree species in the peatland of agusan del sur in mindanao in philippines was examined to deduce the variation of forest structure and observed forest zonation. using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined. the species includes ternstroemia philipp...
Wildfires are of the forest-related disasters caused by inhumane factors. Spreading of these fires is due to the increase of the density of flammable plants. Two important approaches to prevent this occurrence are fuel treatment and fire suppression resources preparedness. In this paper, a mixed integer programming model is proposed based on the covering location and assignment problems which ...
Increasing urbanisation and industrialisation have led to a dramatic reduction in forest area, and now only culturally protected remnants of natural forests and some new plantations remain in most areas of the north of Iran. To investigate the status of the chemical and physical characteristics of soil under these remnant forests and assess the possible impacts of reforestation on soil properti...
An investigation was carried out in some areas of Golestan Province including: Loveh forest, Soosara, Daland forest park, Tooskestan; Gilan Province including Siahkal and Asalem forests; Arasbaran and landscape of urban trees during 1999–2007. In this investigation, based on some morphological, physiological and molecular characteristics and also comparison with standard isolates two species Op...
A lot of absorption lines are in the bluewards of Lyα emission line of quasar which is well-known as Lyαforest. Most of absorption lines in this forest belong to the Lyα absorption of the neutral hydrogen in the inter-galactic medium (IGM). For high redshift quasars and in the continuum with low and medium resolution, there are no many regions without absorption, so that, the quasar continuum i...
Land use change is one of the most important factors of global environmental change. So, understanding and predicting the causes, processes and consequences of land use and land cover has become a major challenge. The Remote Sensing and Geographic Information System (GIS) technologies can be used effectively to detect and quantify of land use changes and its effects on the environment. The pur...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید