نتایج جستجو برای: vegetation density

تعداد نتایج: 453936  

2005
E. Giusti S. Marsili-Libelli

This paper describes the evolution in time and space of the submerged vegetation in a lagoon. This model was developed for the Orbetello Lagoon Management Office to predict the development of both macroalgae and macrophytes and test the actions to favour the latter. Based on a previous model describing the interactions between nutrients and the submerged vegetation, this paper presents a furthe...

2011
Y. Liu R. de Jeu M. McCabe A. van Dijk

Vegetation density plays an important role in water and energy balance. Satellite-based optical and microwave sensors are expected to provide complementary vegetation information. Here we compared NDVI from AVHRR and vegetation optical depth (VOD) from SSM/I over Mongolia from 1988 through 2006. Both products show similar spatial distribution in annual average and are able to capture similar in...

Journal: :جنگل و فرآورده های چوب 0
جواد اسحاقی راد دانشیار گروه جنگل داری دانشکدۀ منابع طبیعی دانشگاه ارومیه، ارومیه، ایران آمنه خانعلیزاده دانشجوی دکتری جنگل داری، دانشکدۀ منابع طبیعی دانشگاه ارومیه، ارومیه، ایران

this study was performed in order to investigate the changes in vegetation and soil properties in compartment no.317 (managed forest) and no.318 (control forest) of jamand district of golband forest in mazandaran (noshahr). for this purpose, random-systematic sampling method with regular grid of 100×200 m was used to locate samples. the plot size was 400 m2 considering to tree and shrub species...

Journal: :مرتع و آبخیزداری 0
جابر شریفی عضو هیت علمی مرکز تحقیقات کشاورزی و منابع طبیعی استان اردبیل ایران. مرتضی اکبرزاده استادیار پژوهشی بخش تحقیقات مرتع مؤسسه تحقیقات جنگل ها ¬و مراتع کشور، ایران.

a major part of the rangelands of iran are located in arid and semi-arid regions. in this climate, rainfall fluctuation is an important factor which affects vegetation and forage production. in dry years that rainfall decreases, surface vegetation and forage production is damaged. this study was conducted on semi-steppic rangelands of ardebil over nine years (1999-2007), to study of vegetation ...

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

primary information about different methods of vegetation sampling is important to researchers to decide about their sampling. in this study we applied five distance methods (closest individual, nearest neighbor, random pairs, point-centered quarter and angle orderd) to estimate plant density in three vegetation types including artemisia sieberi, juncus littoralis and punica granatum in mazanda...

Mapungubwe Cultural Landscape (MCL) woody vegetation was characterized to establish structural and compositional attributes. Stratified random sampling based on major soil types was used and nine plant variables were measured in 137(20x30) m2 sampling plots; these being genera, species and family names; basal circumference; plant height; depth and diameter of tree canopy; number of s...

2011
Akira Yasutake Jin Ping Cheng Masako Kiyono Shimpei Uraguchi Xiaojie Liu Kyoko Miura Yoshiaki Yasuda Nikolay Mashyanov

A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated merc...

2003
Erkan Istanbulluoglu David G. Tarboton Robert T. Pack Charles H. Luce

[1] The controls of forest vegetation, wildfires, and harvest vegetation disturbances on the frequency and magnitude of sediment delivery from a small watershed ( 3.9 km) in the Idaho batholith are investigated through numerical modeling. The model simulates soil development based on continuous bedrock weathering and the divergence of diffusive sediment transport on hillslopes. Soil removal is ...

Journal: :Journal of economic entomology 2006
Mustafa Mirik Gerald J Michels Sabina Kassymzhanova-Mirik Norman C Elliott Roxanne Bowling

Although spectral remote sensing techniques have been used to study many ecological variables and biotic and abiotic stresses to agricultural crops over decades, the potential use of these techniques for greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae) infestations and damage to wheat, Triticum aestivum L., under field conditions is unknown. Hence, this research was conducted to i...

Journal: :Geospatial health 2014
Cristina Ballart Irene Guerrero Xavier Castells Sergio Barón Soledad Castillejo M Magdalena Alcover Montserrat Portús Montserrat Gállego

The aim of the present study was to determine the role of specific environmental and climatic factors affecting the distribution and density of Phlebotomus ariasi and P. perniciosus , the proven vectors for Leishmania infantum in Spain. An entomological study was carried out in July 2006 in the province of Lleida with sticky traps set in their diurnal resting places at altitudes ranging from 86...

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