Retrieving Leaf Area Index and Extinction Coefficient of Dominant Vegetation Canopy in Meijiang Watershed of China Using ETM+ Data

The leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.

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Estimation of vegetation canopy leaf area index and fraction of photosynthetically active radiation absorbed by vegetation from remotely sensed multi-angle and multi-spectral data

IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293) ◽

10.1109/igarss.1999.772123 ◽

2003 ◽

Author(s):

Y. Knyazikhin ◽

R.B. Myneni ◽

Y. Tian ◽

Y. Wang ◽

Y. Zhang

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Spectral Data ◽

Photosynthetically Active Radiation ◽

Remotely Sensed ◽

Vegetation Canopy ◽

Area Index ◽

Active Radiation

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Estimating leaf area index and light extinction coefficients in stands of Douglas-fir (Pseudotsugamenziesii)

Canadian Journal of Forest Research ◽

10.1139/x93-043 ◽

1993 ◽

Vol 23 (2) ◽

pp. 317-321 ◽

Cited By ~ 24

Author(s):

Nicholas J. Smith

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Extinction Coefficient ◽

Photosynthetically Active Radiation ◽

Douglas Fir ◽

Regression Equations ◽

Individual Tree ◽

Area Index ◽

Active Radiation ◽

Wide Range

Both photosynthetically active radiation penetrating the overstory canopy and overstory leaf area index were determined in forty-three 12 × 12 m plots in even-aged Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands. Stands were located on the east side of Vancouver Island, British Columbia, between 300 and 800 m on flat to south-facing slopes and were from a wide range of stem densities and stocking levels. In nine core plots total tree leaf area index was estimated using regression equations from individual-tree stem diameter and stand relative density. A single extinction coefficient did not govern the attenuation of photosynthetically active radiation with respect to leaf area index. For a given leaf area index, the extinction coefficient was smaller at low relative densities because of the presence of canopy gaps. Light attenuation models assuming a single extinction coefficient seriously underpredict stand leaf area index, especially at low stand densities. A modified Beer's Law model was used to predict light penetration, which implicitly accounted for foliage clumping.

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