نتایج جستجو برای: canopy cover and 20 vegetative

تعداد نتایج: 16924356  

2016
Luke Wallace Arko Lucieer Darren Turner Juha Hyyppä Xinlian Liang

This study investigates the potential of unmanned aerial vehicles (UAVs) to measure and monitor structural properties of forests. Two remote sensing techniques, airborne laser scanning (ALS) and structure from motion (SfM) were tested to capture three-dimensional structural information from a small multi-rotor UAV platform. A case study is presented through the analysis of data collected from a...

2014
Oumer S. Ahmed Steven E. Franklin Michael A. Wulder

Disclaimer: The PDF document is a copy of the final version of this manuscript that was subsequently accepted by the journal for publication. The paper has been through peer review, but it has not been subject to any additional copy-editing or journal specific formatting (so will look different from the final version of record, which may be accessed following the DOI above depending on your acc...

2011
Christopher H. R. Goatley David R. Bellwood

Canopies are common among autotrophs, increasing their access to light and thereby increasing competitive abilities. If viewed from above canopies may conceal objects beneath them creating a 'canopy effect'. Due to complexities in collecting 3-dimensional data, most ecosystem monitoring programmes reduce dimensionality when sampling, resorting to planar views. The resultant 'canopy effects' may...

Journal: :مرتع و آبخیزداری 0
لیلا فاضل دهکردی دانش آموخته دکترای مرتع داری، دانشکده منابع طبیعی، دانشگاه تهران، ایران حسین آذرنیوند استاد، دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد علی زارع چاهوکی دانشیار، دانشکده منابع طبیعی، دانشگاه تهران، ایران فرهاد محمودی کهن دانش آموخته کارشناسی ارشد سنجش از دور، دانشگاه کرمان، ایران شهرام خلیقی سیگارودی استادیار، دانشکده منابع طبیعی، دانشگاه تهران، ایران

to identify an appropriate index for monitoring and evaluation of drought, rainfall data obtained from meteorological stations of ilam province from 2000 to 2011 and modis satellite images with 16-day intervals were collected and processed. the standardized precipitation index (spi) was calculated based on rainfall data; therefore, the rainfall data were used for measuring spi and satellite ima...

Journal: :Remote Sensing 2010
Malika Baghzouz Dale A. Devitt Lynn F. Fenstermaker Michael H. Young

In semi-arid environmental settings with sparse canopy covers, obtaining remotely sensed information on soil and vegetative growth characteristics at finer spatial and temporal scales than most satellite platforms is crucial for validating and interpreting satellite data sets. In this study, we used a ground-based NDVI system to provide continuous time series analysis of individual shrub specie...

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2016
A C M Queiroz C R Ribas

We tested the hypothesis of a negative relationship between vegetation characteristics and ant species richness in a Brazilian open vegetation habitat, called candeial. We set up arboreal pitfalls to sample arboreal ants and measured the following environmental variables, which were used as surrogate of environmental heterogeneity: tree richness, tree density, tree height, circumference at the ...

Journal: :Revista de biologia tropical 2013
Eric J Fuchs Tatiana Robles James L Hamrick

The spatial distribution of individuals is a fundamental property of most species and constitutes essential information for the development of restoration and conservation strategies, especially for endangered plant species. In this paper we describe the spatial distribution of different size classes of the endangered tropical tree Guaiacum sanctum and the effect of canopy cover on spatial aggr...

2014
David M J S Bowman Harry J MacDermott Scott C Nichols Brett P Murphy

A grass-fire cycle in Australian tropical savannas has been postulated as driving the regional decline of the obligate-seeding conifer Callitris intratropica and other fire-sensitive components of the regional flora and fauna, due to proliferation of flammable native grasses. We tested the hypothesis that a high-biomass invasive savanna grass drives a positive feedback process where intense fir...

2005
Malcolm L. Bryant Shirish Bhat Jennifer M. Jacobs

The temporal variability of interception losses was measured for contrasting forest communities in the southeastern United States. Throughfall was measured simultaneously at Fort Benning in western Georgia for the five forest communities that are characteristic of the region. The measured interception losses over the study period were 22.3, 18.6, 17.7, 17.6, and 17.4% of the total precipitation...

Journal: :caspian journal of environmental sciences 2013
i. bagheri r. naghdi* a. moradmand jalali

water erosion causes severe soil damage in northern forests of iran which is associated with different rut depths in skid trails. the aim of this study was to assess rutting and soil displacement on skid trails to mitigate water erosion. therefore the research was carried out in eight parcels of district no 3 of shafarood forest in the north of iran. in order to evaluate the amount of erosion i...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید