scholarly journals The relationship between leaf area index and microclimate in tropical forest and oil palm plantation: Forest disturbance drives changes in microclimate

2015 ◽  
Vol 201 ◽  
pp. 187-195 ◽  
Author(s):  
Stephen R. Hardwick ◽  
Ralf Toumi ◽  
Marion Pfeifer ◽  
Edgar C. Turner ◽  
Reuben Nilus ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Oil Palm ◽  
Forest Disturbance ◽  
Plantation Forest ◽  
Area Index ◽  
Oil Palm Plantation ◽  
The Relationship

On the relationship of NDVI with leaf area index in a deciduous forest site

2005 ◽  
Vol 94 (2) ◽  
pp. 244-255 ◽  
Author(s):  
Quan Wang ◽  
Samuel Adiku ◽  
John Tenhunen ◽  
André Granier
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Deciduous Forest ◽  
Forest Site ◽  
Area Index ◽  
Relationship Of ◽  
The Relationship

Relationship between tillering and leaf area index: quantifying critical leaf area index for tillering in rice

2002 ◽  
Vol 138 (3) ◽  
pp. 269-279 ◽  
Author(s):  
X. ZHONG ◽  
S. PENG ◽  
J. E. SHEEHY ◽  
R. M. VISPERAS ◽  
H. LIU
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Planting Density ◽  
Coefficient Of Determination ◽  
Area Index ◽  
N Input ◽  
Major Factors ◽  
The Relationship ◽  
Changing Light ◽  
Input Level

A field study was conducted at the International Rice Research Institute (IRRI), Philippines during the dry seasons of 1997 and 1998 under irrigated conditions. The objectives of this study were to quantify the critical leaf area index (LAIc) at which tillering stops based on the relationship between tillering rate and LAI, and to determine the effect of nitrogen (N) on LAIc in irrigated rice (Oryza sativa L.) crop. Results showed that the relative tillering rate (RTR) decreased exponentially as LAI increased at a given N input level. The coefficient of determination for the equation quantifying the RTR-LAI relationship ranged from 0·87 to 0·99. The relationship between RTR and LAI was affected by N input level, but not by planting density. The N input level had a significant effect on LAIc with a high N input level causing an increase in LAIc. Tillering stopped at LAI of 3·36 to 4·11 when N was not limiting. Under N limited conditions LAIc reduced to as low as 0·98. Transplanting spacing and number of seedlings per hill had little effect on LAIc. Results from this study suggest that LAI and plant N status are two major factors that influence tiller production in rice crops. The possibility that LAI influences tillering by changing light intensity and/or light quality at the base of the canopy where tiller buds and young tillers are located is discussed.

scholarly journals Seasonal patterns of tropical forest leaf area index and CO2exchange

2008 ◽  
Vol 113 (G1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Christopher E. Doughty ◽  
Michael L. Goulden
Keyword(s):  
Tropical Forest ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Seasonal Patterns ◽  
Area Index

CANOPY CHARACTERISTICS OF CONTRASTING CLONES OF CACAO (THEOBROMA CACAO)

2002 ◽  
Vol 38 (3) ◽  
pp. 359-367 ◽  
Author(s):  
A. J. Daymond ◽  
P. Hadley ◽  
R. C. R. Machado ◽  
E. Ng
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Theobroma Cacao ◽  
Light Interception ◽  
Canopy Architecture ◽  
Mature Trees ◽  
Area Index ◽  
Mean Values ◽  
Extinction Coefficients ◽  
The Relationship

Canopy characteristics (leaf area index, fractional light interception, extinction coefficient) of mature trees of ten clonally propagated cacao cultivars were measured over a period of 14 months at an experiment site in Bahia, Brazil. Differences in leaf area index between clones became more pronounced over time. When an approximately constant leaf area index was reached (after about nine months), the leaf area index varied between clones from 2.8 to 4.5. Clonal differences in the relationship between leaf area index and fractional light interception implied differences in canopy architecture, as reflected by the range of extinction coefficients (mean values ranged from 0.63 for the clone TSH-565 to 0.82 for CC-10). The results demonstrate the potential for breeding more photosynthetically efficient cacao canopies.

scholarly journals Monitoring leaf area index at watershed level through NDVI from Landsat-7/ETM+ data

2004 ◽  
Vol 61 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Alexandre Cândido Xavier ◽  
Carlos Alberto Vettorazzi
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Index ◽  
Hydrological Cycle ◽  
Riparian Forest ◽  
Empirical Relationships ◽  
Area Index ◽  
Landsat 7 ◽  
The Mean ◽  
The Relationship

Leaf area index (LAI) is an important parameter of the vegetation canopy, and is used, for instance, to estimate evapotranspiration, an important component of the hydrological cycle. This work analyzed the relationship between LAI, measured in field, and NDVI from four dates (derived from Landsat-7/ETM+ data), and with such vegetation index, to generate and analyze LAI maps of the study area for the diverse dates. LAI data were collected monthly in the field with LAI-2000 equipment in stands of sugar cane, pasture, corn, eucalypt, and riparian forest. The relationships between LAI and NDVI were adjusted by a potential model; 57% to 72% of the NDVI variance were explained by the LAI. LAI maps generated by empirical relationships between LAI and NDVI showed reasonable precision (standard error of LAI estimate ranged from 0.42 to 0.87 m² m-2). The mean LAI value of each monthly LAI map was shown to be related to the total precipitation in the three previous months.

scholarly journals Leaf area index mapping with optical methods and allometric models in SMEAR flux tower footprint at Järvselja, Estonia

2015 ◽  
Vol 63 (1) ◽  
pp. 85-99
Author(s):  
Marta Mõistus ◽  
Mait Lang
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Point Cloud ◽  
Forest Growth ◽  
Height Distribution ◽  
Area Index ◽  
Flux Tower ◽  
Gap Fraction ◽  
Plant Area Index ◽  
The Relationship

AbstractLeaf area index (LAI) characterizes the amount of photosynthetically active tissue in plant canopies. LAI is one of the key factors determining ecosystem net primary production and gas and energy exchange between the canopy and the atmosphere. The aim of the present study was to test different methods for LAI and effective plant area index (PAIe) estimation in mixed hemiboreal forests in Järvselja SMEAR Estonia (Station for Measuring Ecosystem-Atmosphere Relations) flux tower footprint. We used digital hemispherical images from sample plots, forest management inventory data, allometric foliage mass models, airborne discrete-return recording laser scanner (ALS) data and multispectral satellite images. The free ware program HemiSpherical Project Manager (HSP) was used to calculate canopy gap fraction from digital hemispherical photographs taken in 25 sample plots. PAIewas calculated from the gap fraction for up-scaling based on ALS point cloud metrics. The all ALS pulse returns-based canopy transmission was found to be the most suitable lidar metric to estimate PAIein Järvselja forests. The 95-percentile (H95) of lidar point cloud height distribution correlates very well with allometric regression models based LAI and in birch stands the relationship was fitted with 0.7 m2m−2residual error. However, the relationship was specific to each allometric foliage mass model and systematic discrepancies were detected at large LAI values between the models. Relationships between the spectral reflectance and allometric LAI were not good enough to be used for LAI mapping. Therefore, airborne laser scanning data-based PAIemap was created for areas near SMEAR tower. We recommend to establish a network of permanent sample plots for forest growth and gap fraction measurements into the flux footprint of SMEAR Estonia flux tower in Järvselja to provide consistent up to date data for interpretation of the flux measurements.

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