نتایج جستجو برای: reduction of forest canopy

تعداد نتایج: 21203187  

2013
C. Joshi J. van Andel A. Skidmore J. de Leeuw I. V. Duren

In this paper, the researchers investigate the vegetative growth of Chromolaena odorata and the infl uence of light intensity on the understorey environment of Shorea robusta forest at Chitwan in south-central Terai, Nepal. C. odorata is a clonally growing shrub and typically consists of several clones with an underground “cormous organ” (a modifi ed stem to store food reserve; here after “corm...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Gregory P Asner Daniel Nepstad Gina Cardinot David Ray

Amazônia contains vast stores of carbon in high-diversity ecosystems, yet this region undergoes major changes in precipitation affecting land use, carbon dynamics, and climate. The extent and structural complexity of Amazon forests impedes ground studies of ecosystem functions such as net primary production (NPP), water cycling, and carbon sequestration. Traditional modeling and remote-sensing ...

Journal: :Ecology 2010
Molly A Cavaleri Steven F Oberbauer David B Clark Deborah A Clark Michael G Ryan

Both within and between species, leaf physiological parameters are strongly related to leaf dry mass per area (LMA, g/m2), which has been found to increase from forest floor to canopy top in every forest where it has been measured. Although vertical LMA gradients in forests have historically been attributed to a direct phenotypic response to light, an increasing number of recent studies have pr...

Journal: :Ecological applications : a publication of the Ecological Society of America 2015
Michael Toomey Mark A Friedl Steve Frolking Koen Hufkens Stephen Klosterman Oliver Sonnentag Dennis D Baldocchi Carl J Bernacchi Sebastien C Biraud Gil Bohrer Edward Brzostek Sean P Burns Carole Coursolle David Y Hollinger Hank A Margolis Harry Mccaughey Russell K Monson J William Munger Stephen Pallardy Richard P Phillips Margaret S Torn Sonia Wharton Marcelo Zeri Andrew D And Andrew D Richardson

The proliferation of digital cameras co-located with eddy covariance instrumentation provides new opportunities to better understand the relationship between canopy phenology and the seasonality of canopy photosynthesis. In this paper we analyze the abilities and limitations of canopy color metrics measured by digital repeat photography to track seasonal canopy development and photosynthesis, d...

2004
R F Keim A E Skaugset T E Link A Iroumé

Although it is well known that forest canopies reduce the amount and intensity of precipitation at the ground surface, little is known about how canopy interception modifies extreme events. This research investigated the effects of forest cover on intensity-duration-frequency relationships using a stochastic model to extrapolate measured rainfall and throughfall to throughfall expected during e...

2013
Arnold F. Sitompul Curtice R. Griffin Nathaniel D. Rayl Todd K. Fuller

Increasingly, habitat fragmentation caused by agricultural and human development has forced Sumatran elephants into relatively small areas, but there is little information on how elephants use these areas and thus, how habitats can be managed to sustain elephants in the future. Using a Global Positioning System (GPS) collar and a land cover map developed from TM imagery, we identified the habit...

2010
Juan Cuesta Patrick Chazette Tristan Allouis Pierre H. Flamant Sylvie Durrieu Joseph Sanak Pascal Genau Dominique Guyon Denis Loustau Cyrille Flamant

We have developed a new airborne UV lidar for the forest canopy and deployed it in the Landes forest (France). It is the first one that: (i) operates at 355 nm for emitting energetic pulses of 16 mJ at 20 Hz while fulfilling eye-safety regulations and (ii) is flown onboard an ultra-light airplane for enhanced flight flexibility. Laser footprints at ground level were 2.4 m wide for a flying alti...

2000
H. Voipio Smolander

Several radiative techniques have been developed for inverse estimation of the leaf area indes (LAI) using optical data measured below the canopy (e.g. hemispherical photography) or above the canopy (remote sensing). In the inversion, a model of the three-dimensional distribution of leaves in the canopy is used to define the required relation between LAI and canopy transmittance and reflectance...

Importance of probability distribution functions in natural resource studies is increasing due to their effective roles in better understanding of vegetation structure and providing conceptual models of quantitative indices of plant species. The present study was performed to model the distribution of height and canopy area of Cionura erecta L. shrub, using probability distribution functions in...

2013
Maria Baimas-George

Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient composition o...

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