Biomass was harvested from six vegetation types along a toposequence on a floodplain terrace of the Sagavanirktok River in the northern foothills of the Brooks Range , Alaska (68degrees 46' N, 148 degrees 51' W 50m). The vegetation sites are; upland tussock tundra, "hilltop heath", a "hillslope shrub-lupine", a "footslope Equisetum", a wet sedge tundra, and a "riverside willow".
Data set ID:
EML revision ID:
Field: Samples are obtained by collecting all aboveground biomass and belowground stems and rhizomes in 20 x 20 cm quadrats, located randomly along line transects within the site. Normally, 4 or 5 quadrats are collected along each of 4 transects at each site or treatment. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.)
Lab: Each quadrat is first sorted into species and then into tissue type. Depending on the harvest, tissue types can be broad categories, i.e. above and below, or more detailed, i.e. inflorescences, new growth, old growth, etc. The separated samples are dried for several days at approximately 65 ºC and then weighed. The dry weight for each quadrat, species and tissue type is recorded. Finally the samples from all quadrats in a transect are combined according to tissue type. Samples are then returned to Woods Hole for nutrient analysis.
Notes: Error Handling
In the original data file there existed three types of errors
-888 Indicates missing data
-999 Indicates missing a value which was probably included
in another tissue type.
-777 Indicates that leaves and stems were not separated,
weights were entered as leaf wt. This occurs
only for Cassiope.
In order to calculate totals, averages, etc., the above errors were treated as listed below.
-888 Converted to a blank which is treated as a missing value.
Quadrats with missing values are excluded from
-999 This value is converted to a 0.These quadrats are included
in subsequent analysis.
-777 This value is also converted to a 0. These quadrats
are included in subsequent analysis.
Note: For the Willow site there are four values which result from the sum of a -999 error and a measured value.
Log of changes:
17Mar95. Added comma delimited data and document to database. Original file is in excel 5, 88gssabm.xls. Jim L.
10Nov2004. Updated the variable names and site names. Added title to metadata. JL
Version 2: Created Excel metadata form. Changed title, filename to full year and added attribut table. 10Jan06 Jim L
Version 3: Added LTERNET Data Access server proxy for Excel and comma delimited data files.
Version 4: Update LTERNET Data Access server proxy link for Excel and comma delimited data files. Changed from knb to das in url.
Version 5: Updated the metadata sheet to the new form and eml to 2.1 Jim L 9Jul2012
Version 6: Taxonomic coverage data updated. Updated to newer metadata form (with sites sheet). CH March 2013.
Version 7: Checked keywords against the LTER network preferred list and replaced non-preferred terms. Jim L 27Jan14
Version 8: Changed Distribution URL since the LTER network DAS system is being discontinued. Jim L 9Apr2015
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