نتایج جستجو برای: canopy

تعداد نتایج: 14776  

2013
Leah Wasser Rick Day Laura Chasmer Alan Taylor

Estimates of canopy height (H) and fractional canopy cover (FC) derived from lidar data collected during leaf-on and leaf-off conditions are compared with field measurements from 80 forested riparian buffer plots. The purpose is to determine if existing lidar data flown in leaf-off conditions for applications such as terrain mapping can effectively estimate forested riparian buffer H and FC wit...

2012
John F. Weishampel Jessica N. Hightower Arlen F. Chase Diane Z. Chase

Tropical rainforest clearing and degradation significantly reduces carbon sequestration and increases the rate of biodiversity loss. There has been a concerted international effort to develop remote sensing techniques to monitor broad-scale patterns of forest canopy disturbance. In addition to loss of natural resources, recent deforestation in Mesoamerica threatens historic cultural resources t...

Journal: :Annals of botany 2010
Ian R Johnson John H M Thornley Jonathan M Frantz Bruce Bugbee

BACKGROUND AND AIMS The distribution of photosynthetic enzymes, or nitrogen, through the canopy affects canopy photosynthesis, as well as plant quality and nitrogen demand. Most canopy photosynthesis models assume an exponential distribution of nitrogen, or protein, through the canopy, although this is rarely consistent with experimental observation. Previous optimization schemes to derive the ...

Journal: :Annals of botany 2006
Koichi Takahashi Agus Rustandi

BACKGROUND AND AIMS Growth in trunk height in canopy openings is important for saplings. How saplings increase height growth in canopy openings may relate to crown architectural constraints. Responses of crown development to canopy openings in relation to trunk height growth were studied for saplings (0.2-2.5 m tall) of eight tropical submontane forest tree species in Indonesia. The results of ...

2003
R A DONALDSON

The primary role of a crop canopy is to capture sunlight that can be converted to biomass, including sucrose stored in stalks. Canopy development also has a bearing on the amount of water used by the crop and how soon weeds are shaded out. Cultivars are known to differ in the rate of canopy closure in the field, and also differ in traits that determine canopy development, such as leaf size and ...

Journal: :Applied optics 1995
J M Chen J Cihlar

Optical instruments currently available for measuring the leaf-area index (LAI) of a plant canopy all utilize only the canopy gap-fraction information. These instruments include the Li-Cor LAI-2000 Plant Canopy Analyzer, Decagon, and Demon. The advantages of utilizing both the canopy gap-fraction and gap-size information are shown. For the purpose of measuring the canopy gap size, a prototype s...

2006
Margaret D. Lowman

The forest canopy harbors a diverse assemblage of plants of many different growth habits. The reproductive parts of tall trees, many epiphytes, and lianas may exist only in the upper canopy. Access to these upper regions is essential to identify canopy plants and to collect and document voucher specimens for a particular forest region. The majority of botanists, however, have relied on collecti...

2017
Eduardo González-Ferreiro Stéfano Arellano-Pérez Fernando Castedo-Dorado Andrea Hevia José Antonio Vega Daniel Vega-Nieva Juan Gabriel Álvarez-González Ana Daría Ruiz-González

The fuel complex variables canopy bulk density and canopy base height are often used to predict crown fire initiation and spread. Direct measurement of these variables is impractical, and they are usually estimated indirectly by modelling. Recent advances in predicting crown fire behaviour require accurate estimates of the complete vertical distribution of canopy fuels. The objectives of the pr...

2006
Wei Wang Scott B. Franklin Yi Ren John R. Ouellette

Gap characteristics and effects of gaps on plasticity of Fargesia qinlingensis and tree regeneration were studied under canopy, and in small, medium, and large gaps in a mixed hardwood-conifer forest in the Qinling Mountains, China. Gap formation was mainly tree snapping (40%). Gapmakers were dominated by Betula albosinensis and Abies fargesii (85%). Gap area ranged from 23.8 to 594.2 m and ave...

2007
Silke Begiebing Heike Bach Wolfram Mauser

Spatially distributed information on canopy parameters is an important input to precision agriculture. Remote sensing data, and especially high-resolution hyperspectral data of sensors such as the multi-directional satellite-sensor CHRIS or the airborne spectrometer AVIS provide such information. In order to derive the canopy parameters leaf area index and fraction of mature material as well as...

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