نتایج جستجو برای: eg percentage of canopy cover
تعداد نتایج: 21181098 فیلتر نتایج به سال:
BACKGROUND Cryopreservation of mammalian ovaries has been reported with different levels of success. Cryopreservation of ovarian tissue may be a potential alternative for treatment of infertility and many attempts have been done to improve the efficiency of ovarian cryopreservation. The objective of the present study was to compare the direct cover vitrification (DCV) with ethylene glycol (EG),...
The present study eas aimed to evaluate the potential of ALS data in estimation of individual canopy cover area and tree heights for the part of Shast Kalate of Gorgan. In this study 117 tree that located in dominant forest story and without overlay with adjacent trees, were selected. Center coordinates of sample trees were determined using DGPS system. Individual canopy area and tree heights w...
Accurate estimates of forest canopy are essential for the characterization of forest ecosystems. Remotelysensed techniques provide a unique way to obtain estimates over spatially extensive areas, but their application is limited by the spectral and temporal resolution available from these systems, which is often not suited to meet regional or local objectives. The use of unmanned aerial vehicle...
Humans are rapidly altering natural systems, leading to changes in the distribution and abundance of species. However, so many changes are occurring simultaneously (e.g., climate change, habitat fragmentation) that it is difficult to determine the cause of population fluctuations from correlational studies. We used a manipulative field experiment to determine whether forest canopy cover directl...
The study of plant communities is the best way to learn about vegetation structure and distribution as well as various interactions among the plants in an ecosystem. Elevation factor plays a vital role in plant distribution that ultimately leads to specific phytogeographic regions. This study evaluated the changes in species composition, density, frequency, canopy cover and palatability of spec...
this research aimed to evaluate the effect of planting seasons (autumn and spring) on 10 accessions of two species of astragalus effusus and astragalus brachyodontus in the field condition (homand absard station, damavand). after preparing the seedbed, the plant species were planted on two lines in 2 m, where the spacing between the lines of each accession was 0.5 m, and the spacing between the...
The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require informatio...
Choosing management strategies are influencing the vegetation characteristics and plant diversity in rangelands. We have studied the effects of three management treatments including overgrazing, exclusure, and exclusure with restoration operations on vegetation characteristics of plant cover, composition, and diversity in Kiasar Chardange summer rangelands. In each management treatment, three r...
Remote sensing technology is widely used in environmental and agricultural research, and nowadays it has become a valuable and reliable source of information for the management of crop production and assessment of global supply and demands for these products. The objective of this study was to investigate the feasibility of using MODIS data and vegetation indices based on sugar beet growth moni...
We used a predictive model to map canopy cover of vegetation over seven feet in height (“tall woody vegetation”) at 30-meter resolution over nearly 29 million acres within and adjacent to the range of the greater sage-grouse in Oregon (Figure 1). Texture measures computed at various resolutions from colorinfrared aerial photography provided the main source of predictor data used to produce the ...
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