نتایج جستجو برای: leaf area index lai

تعداد نتایج: 1018301  

Journal: :Remote Sensing 2017
Shihua Li Leiyu Dai Hongshu Wang Yong Wang Ze He Sen Lin

The leaf area density (LAD) within a tree canopy is very important for the understanding and modeling of photosynthetic studies of the tree. Terrestrial light detection and ranging (LiDAR) has been applied to obtain the three-dimensional structural properties of vegetation and estimate the LAD. However, there is concern about the efficiency of available approaches. Thus, the objective of this s...

2014
Jan SABOL Tomáš MIKITA

Leaf area index (LAI) can be measured either directly, using destructive methods, or indirectly using optical methods that are based on the tight relationship between LAI and canopy light transmittance. Third, innovative approach for LAI measuring is usage of remote sensing data, especially airborne laser scanning (ALS) data shows itself as a advisable source for purposes of LAI modelling in la...

Journal: :Journal of environmental biology 2007
A Almodares R Taheri S Adeli

The carbohydrate contents of sweet sorghum (Sorghum bicolor L. Moench) is an important industrial factor for crystal sugar or bioethanol production. In this study the relationship between growth analysis and carbohydrate contents were studied to recognize the best growth stages for sweet sorghum harvesting. Five sweet sorghum cultivars and four sweet sorghum lines were evaluated for leaf area i...

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...

Journal: :Tree physiology 1995
N Bréda A Granier G Aussenac

To quantify the effects of crown thinning on the water balance and growth of the stand and to analyze the ecophysiological modifications induced by canopy opening on individual tree water relations, we conducted a thinning experiment in a 43-year-old Quercus petraea stand by removing trees from the upper canopy level. Soil water content, rainfall interception, sap flow, leaf water potential and...

Journal: :Proceedings. Biological sciences 2012
Peter B Reich

Quantifying the mechanistic links between carbon fluxes and forest canopy attributes will advance understanding of leaf-to-ecosystem scaling and its potential application to assessing terrestrial ecosystem metabolism. Important advances have been made, but prior studies that related carbon fluxes to multiple canopy traits are scarce. Herein, presenting data for 128 cold temperate and boreal for...

Journal: :Remote Sensing 2015
Yuechan Shi Jindi Wang Jun Qin Yonghua Qu

Upscaling in situ leaf area index (LAI) measurements to the footprint scale is important for the validation of medium resolution remote sensing products. However, surface heterogeneity and temporal variation of vegetation make this difficult. In this study, a two-step upscaling algorithm was developed to obtain the representative ground truth of LAI time series in heterogeneous surfaces based o...

2010
Shuai Gao Liang Guo Jie Wu Lu Yu Chaoyang Wu Yu Meng Ting Mei Liping Zhou

One method of estimating vegetation Leaf Area Index (LAI) using ENVISAT-ASAR data was presented based on the ground experiment data in Heihe district, northwest China. Firstly, the vegetation species was analyzed and classified in this area and the category covered the cultural vegetation, shrub, grass, desert, needle forests, and broadleaf forests. With support of experiment data and other mat...

2003
Kenan Diker Walter C. Bausch

Estimating the spatial variability of various plant parameters during the growing season can assist in timely correction of stress conditions within a field. This research illustrates that the nitrogen reflectance index (NRI) developed to estimate plant nitrogen status can be used to estimate plant parameters and yield potential. The study was conducted on two experimental maize sites. Selected...

2009
Adrian V. Rocha Gaius R. Shaver

A two band Enhanced Vegetation Index (EVI2) without the blue band reflectance has recently been developed as a proxy for the phenology, quantity, and activity of vegetation. We compared the ability of EVI2 and the more commonly used Normalized Difference Vegetation Index (NDVI) to resolve differences in surface greenness and Leaf Area Index (LAI) among three sites located along a burn severity ...

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