نتایج جستجو برای: and forest
تعداد نتایج: 16850233 فیلتر نتایج به سال:
At present, there is no conventional scientific method to evaluate the area of the burnt regions of forests and in this field, the related organizations use different methods and variables. Also, the speed in performing the processes of area computing and damage evaluation, especially in the extensive damaged forest regions is very slow; consequently, the expression of results takes more ti...
میکروآران ای ها یک کلاس از آران ای های کوچک غیرکدشونده تنظیمی هستند که اهمیت بسیار زیادی در خاموش کردن ژن های پست-ترنسکریپشنال دارند. آن ها اکثراً با چسبیدن به بخش 3’utr( three prime untranslated region) مسنجر آران ای های هدف، میزان ژن ها را به یکی از دو روش بریدن یا مهار کردن تنظیم می کنند. دانشمندان در ابتدا اهداف میکرو آر ان ای ها را با انجام آزمایش مشخص می کردند. با این وجود، به خاطر پرهزینه...
quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...
Assessment of forest structure and their spatial patterns are essential for managing and evaluation of forest ecosystems. This study was conducted at the Zagros forests in Kermanshah to evaluate the forest structural characteristics and their spatial distribution. Data was collected from 25 plots (400 m2) in a 100 m × 100 m systematic sampling grid. The spacing between plots was 50 m. In each p...
The aim of the present study was to evaluate the spatial and temporal changes of NPP in different biomes of Isfahan province from 2000 to 2014 and their response to climatic factors. For this purpose, the NPP data of the MODIS satellite were collected and the map of climatic variables was produced using various interpolation methods. The investigation of the spatial and temporal variations of N...
management of the forest resources and related activities has significant effects on the environment. applying the environmental impact assessment (eia) provides a basis for improving forest management plans. however, in the developing countries such as iran, there have been so far no serious endeavors and research to undertake the eia of the various practices affecting the forest resources, de...
Ephedra is a dioecious shrub belongs to the Ephedraceae family. Almost all commercial applications of Ephedra extracts is derived from the ephedrine alkaloids found in the evergreen stems. The purpose of this study was to investigate seed germination in green house condition and total alkaloid and ephedrine amounts measurement. The Ephedra seeds were collected from Bojnoord region and germinate...
canopy gaps are one of the most important structural features of forest ecosystems, and studying of them can have useful results and implications for forest management. the aim of this study is investigation of characteristics and regeneration within canopy gaps in an intact beech stand in the shastkalateh experimental forest of hyrcanian region, north of iran. all canopy gaps and related fores...
some soil physical and chemical characteristics were analyzed in order to reveal the relationship between forest soils and regeneration patches. gorazbon district of kheyrud was selected as a case study for the research area. all regeneration patches were recorded using gps device. to assess the spatial structure and to quantify the metrics of regeneration patches, analyzing of landscape metric...
Estimation and mapping of forest resources are preconditions for management, planning and research. In this study, we applied kriging interpolation of geostatistics for estimation and mapping of forest stock at-tributes in a natural, uneven-aged, unmanaged forest in the Caspian region of northern Iran. The site of the study has an area of 516 ha and an elevation that ranges from 1100 to 1450 m ...
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