Plant biomass in arctic heath experimental plots. Plots set up in 1989 with nitrogen, phosphorus, nitrogen plus phosphorus and a shade treatment were harvested for above ground biomass. Root mass was also measured on a smaller subsample.
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The Arctic LTER heath plots are located in a dry dwarf-shrub, fruticose-lichen tundra near the north end of Toolik Lake. They are laid out in three blocks of randomized 5x20 m plots. Each block contains the following treatments: control (CT), nitrogen plus phosphorus (NP), nitrogen (N) and phosphorus (P). Shade (SH) and shade plus nitrogen and phosphorus (SHNP) are replicated in only 2 blocks (SHNP was not harvested). The plots were established in June 1998. Nitrogen and/or phosphorus plots receive an annual treatment of 10 g/m2 nitrogen (as NH4NO3) and/or 5 g/m2 phosphorous (as triple superphosphate). Shade houses, simple 'A' frames covered with 50% light reducing shade cloth, are covered annually in late May or early June and uncovered at the end of August or early September.
Calculations: Units; Tissue mass data are expressed in g/quadrat (400 cm2). Multiply by 25 to get g/m2.
Reference Citations: Shaver, G. R., and F. S. Chapin. 1991. Production biomass relationships and element cycling in contrasting arctic vegetation types. Ecological Monographs 61:1-31.
In N, P, NP, and CT plots, five quadrats (20 cm x 20 cm) were located at random along a 10 m transect that was about 40 cm from the south edge of the east end. In the shade plots, quadrats were located haphazardly in the eastern third of each shade frame by tossing a knife, spinning, into the plot and taking a quadrat at the point of the knife. Each quadrat was harvested to a depth of about 10 to 15 cm, which included most roots. Aboveground biomass was considered "within" the quadrat if it was associated with a meristem that was within the quadrat. All vascular plants were sorted to species while mosses and lichens were lumped. Categories included: new above, old above, and below ground stems/rhizomes. Leaves and stems for the new or old category were not separated. Only the green mass of the mosses and the total live mass of the lichens were sorted. Coarse roots (greater than 1 mm in diameter) were separated in all quadrats. To estimate fine root mass, a 50-100 g sample of homogenized loose soil from each quadrat in block 1 was taken and all the fine roots were separated, dried and weighed. Weights of the total soil, the subsample and the dried roots were recorded.
All samples were dried at 50-70 degrees C for several days and weighed to nearest milligram. Samples were then returned to Woods Hole for archiving and future nutrient analysis. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.)
Log of changes:
5Mar00 Separated comma delimited data from Excel file. JL
27Oct04 completed the variable description and update the file name to 1996. JL
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DATE RECEIVED: Sept 1996
DATA FILE ENTERED BY: Jim Laundre
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NAME: Jim Laundre, Gus Shaver
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