GLBRC Sustainability Data Catalog

Leaf Area Index (LAI) — GLBRC Biofuel Cropping System Experiment

Data in the KBS LTER core database may not be published without written permission of the lead investigator or project director Full terms of use

Leaf Area Index data from the KBS GLBRC Intensive Site (BCSE) from 2009 to 2017. From 2009 to 2013 the data was collected with a Licor LAI-2000 meter and since 2013 we have used an AccuPar LP-80 Ceptometer.

This datatable is part of the GLBRC Annual Net Primary Productivity dataset. This dataset contains the aboveground biomass data. Annual net primary production (ANPP) data is measured at peak biomass for a given treatment. Additional ANPP measurements are made where appropriate such as occasional destructive harvests for poplar. See the ANPP protocols for descriptions of the sampling and measurement methods for each of the treatments. Below ground net primary production (BNPP) are available for these same sites.


Experiment: GLBRC Biofuel Cropping System Experiment
Data available from: June 2009 to October 2017
Dataset: GLBRC082
Datatable ID: GLBRC082-007.160
Repository link:
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Last Updated 2023-05-23
Variate Description Units
sample date date and time of measurement, the plus sign indicates the time relative to Universal Coordinated Time (UCT).
local time the time in the eastern time zone either standard time or daylight saving time depending on the date.
treatment experimental treatment
replicate replicate nested within treatment
direction direction and plant number
lai leaf area index m^2/m^2
sel standard error of lai m^2/m^2
difn fraction of sky visible number
mta mean tilt angle degree
sem standard error of MTA degree
smp number of sample pairs used number
comments notes about the data row
instrument the instrument used to measure LAI
mean above par mean PAR above the canopy in micromoles/(m^2 s)
mean below par mean PAR below the canopy in micromoles/(m^2 s)
tau ratio between the above and below canopy PAR dimensionless
chi (leaf distribution parameter): ratio of the projected area of an average canopy element (a leaf, for example) on a horizontal plane to its projection on a vertical plane; the default value for χ is 1.0, which assumes the canopy angle distribution to be spherical.
fb (fractional beam radiation): ratio of direct beam radiation coming from the sun to radiation gathered from all ambient sources, like the atmosphere, or reflected from other surfaces
zenith angle angle between the point in the sky directly overhead vertical, called the zenith (0°), and the position of the sun. The angle is calculated based on the global position, time of day, and location degree

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Data Excerpt

sample_date local_time treatment replicate direction lai sel difn mta sem smp comments instrument mean_above_par mean_below_par tau chi fb zenith_angle
2017-10-27 12:52:00 +0000 2017-10-27 08:52:00 UTC G8 R1 EP3 0.39 LAI AccuPAR LP-80 Ceptometer 11.2 8.1 0.719 1.0 0.02 83.0
2017-10-27 12:51:00 +0000 2017-10-27 08:51:00 UTC G8 R1 EP1 0.67 LAI AccuPAR LP-80 Ceptometer 10.9 6.1 0.56 1.0 0.02 83.0
2017-10-27 12:51:00 +0000 2017-10-27 08:51:00 UTC G8 R1 EP2 0.72 LAI AccuPAR LP-80 Ceptometer 11.0 6.0 0.542 1.0 0.02 83.0
2017-10-27 12:50:00 +0000 2017-10-27 08:50:00 UTC G8 R1 WP3 0.79 LAI AccuPAR LP-80 Ceptometer 11.3 5.7 0.505 1.0 0.02 83.0
2017-10-27 12:48:00 +0000 2017-10-27 08:48:00 UTC G8 R1 WP2 0.79 LAI AccuPAR LP-80 Ceptometer 12.1 6.2 0.51 1.0 0.02 84.0
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