Copass_Council_LeafAreaI_readme Data set name: Copass_Council_LeafAreaI.xls Worksheets: LAI, Summary Investigator Names: Catharine Copass Terry Chapin A. Dave McGuire Jason Beringer Contact for data questions: Catharine Copass ftcdc@uaf.edu Dept. Biology and Wildlife University of Alaska Fairbanks 99775-6100 907.474.7929 Grant: OPP 9732126 Data Set Overview: These are point based measurements of Leaf Area Index (LAI) from the Council Grids. The LAI data were collected with the Licor LAI-2000 Canopy Analyzer on multiple dates, including approximately peak season biomass during the 1999 field season. Averages and standard deviations have been calculated.The location and name of the grids is as follows: C1 Forest N64deg54.456' W163deg40.469' C2 Tundra N64deg50.499' W163deg41.591' C6 Low Shrub N64deg53.47' W163deg38.61' C3 Tall Shrub N64deg56.141' W164deg44.142' C4 Woodland N64deg53.997' W163deg39.863' Instrument Description: The LAI-2000 calculates LAI and other attributes from radiation measurements made with a "fish-eye" optical sensor (148° field-of-view). Measurements made above and below the canopy are used to determine canopy light interceptionat 5 angles, from which LAI is computed using a model of radiative transfer in vegetative canopies. See http://env.licor.com/Products/AreaMeters/lai2000/2000.htm for more information. Data Collection: Sampling Dates were as follows for the sites: C2 (Tundra): 6/23 and 8/13 C6 (Low Shrub): 6/22 and 7/21 C3 (Tall Shrub): 6/25 C4 (Woodland): 6/24 and 8/24 C1 (Forest): 6/22 We used the 90 degree field of view restrictor. Best effort was made to take measurements under stable, overcast conditions. The data were processed using the Licor- LAI software, which calculates LAI based on paired above and below canopy measurements nearest in time. Data Format: The data is in an Excel file, with cases referenced by the grid point number and variables listed by site number and date of sampling. Missing data are indicated by "---" Data Remarks: It is unlikely that zero values represent true zero leaf index, as the sensor head is approximately 1cm. Prostrate vegetation, moss and lichen are underrepresented in this method.