نتایج جستجو برای: leaf area index lai

تعداد نتایج: 1018301  

2006
Alfredo Huete Edward Glenn Allan Matthias Stuart Marsh Kurtis Thome Abdullah F. Rahman Ho Jin Kim Youngwook Kim Lisa Goins Judith Ellwanger Veronica Hirsch Alicia Velasquez

Vegetation indices (VI ) play an important role in studies of global climate and biogeochemical cycles, and are also positively related to many biophysical parameters and satellite products, such as leaf area index (LAI), gross primary production (GPP), land surface water index (LSWI) and land surface temperature (LST). In this study we found that VI’s had strong relationships with some biophys...

Journal: :Tree physiology 2004
Guillaume Simioni Jacques Gignoux Xavier Le Roux Raphaëlle Appé Daniele Benest

Foliage growth, mass- and area-based leaf nitrogen concentrations (Nm and N a) and specific leaf area (SLA) were surveyed during a complete vegetation cycle for two co-occurring savanna tree species: Crossopteryx febrifuga (Afzel. ex G. Don) Benth. and Cussonia arborea A. Rich. The study was conducted in the natural reserve of Lamto, Ivory Coast, on isolated and clumped trees. Leaf flush occurr...

2010
Jing M. Chen Jan Pisek Feng Deng Stephen Plummer

Leaf area index, defined as one half the total (all sided) leaf area per unit ground surface area [1], is a key vegetation structural parameter used in most ecological, hydrological and meteorological models to describe physical and biological processes associated with vegetated surfaces and their interaction with the atmosphere. The accuracy of existing global LAI parameters is not yet satisfa...

2008
C. SONG

Leaves are the primary interface where energy, water and carbon exchanges occur between the forest ecosystems and the atmosphere. Leaf area index (LAI) is a measure of the amount of leaf area in a stand, and the tree crown size characterizes how leaves are clumped in the canopy. Both LAI and tree crown size are of essential ecological and management value. There is a lot of interest in extracti...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2014
Holly Croft Jing M. Chen Yongqin Zhang

Spatial and temporal variations in canopy structure and leaf biochemistry have considerable influence on fluxes of CO2, water and energy and nutrient cycling in vegetation. Two vegetation indices (VI), NDVI and Macc01, were used to model the spatio-temporal variability of broadleaf chlorophyll content and leaf area index (LAI) across a growing season. Ground data including LAI, hyperspectral le...

2016
Tim G Reichenau Wolfgang Korres Carsten Montzka Peter Fiener Florian Wilken Anja Stadler Guido Waldhoff Karl Schneider

The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-veg...

2012
S. Khosravi M. Namiranian H. Ghazanfari A. Shirvani

The focus of the present study is the estimation of leaf area index (LAI) and the assessment of allometric equations for predicting the leaf area of Lebanon oaks (Quercus libani Oliv.) in Iran’s northern Zagros forests. To that end, 50 oak trees were randomly selected and their biophysical parameters were measured. Then, on the basis of destructive sampling of the oak trees, their specific leaf...

1999
M. Pospišil

Three-year field trials were set up on eutric brown soil in northwestern Croatia (Zagreb) with the objective to determine the effect of plant density and nitrogen rates on the formation and size of leaf area of seed sugar beet, and on the yield and seed quality in seed production without transplanting. Investigations should also reveal how much the yield and quality of sugar beet seed depend on...

2015
Gabriella Balacco Benedetto Figorito Eufemia Tarantino Andrea Gioia Vito Iacobellis

The vegetation space-time variability during 1999-2010 in the North of the Apulian region (Southern Italy) was analysed using SPOT VEGETATION (VGT) sensor data. Three bands of VEGETATION (RED, NIR and SWIR) were used to implement the vegetation index named reduced simple ratio (RSR) to derive leaf area index (LAI). The monthly average LAI is an indicator of biomass and canopy cover, while the d...

2003
Paul V. Bolstad James M. Vose

Leaf area index (LAI) is an important structural characteristic of forest ecosystems which has been shown to be strongly related to forest mass and energy cycles and forest productivity. LAI is more easily measured than forest productivity, and so a strong relationship between LAI and productivity would be a valuable tool in forest management. While a linear relationship has been observed betwe...

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