Above ground plant and below ground stem biomass, percent nitrogen, and percent carbon were measured in the Arctic LTER dry heath tundra experimental plots. Treatments included control, and nitrogen and phosphorus amended plots for 10 years, and exclosure plots with and without added nitrogen and phosphorus.
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The LTER dry heath (DH) exclosure treatments were set up in 1996 on extra 5 x 20 meter plots within the three-block design of the 1989 LTER dry heath experimental site. On each plot, a 5 x 10 meter section was fenced with large mesh (4-inch square mesh) to exclude large mammals. Within this fence a 5 x 5 meter plot was fenced with a small mesh (1/2-inch square mesh) to exclude both large and small mammals. In each block two fenced plots were set up: a plot with no fertilizer and a plot with annual fertilization (NP) treatments added as 10g/m2 nitrogen (as NH4NO3) and 5 g/m2 phosphorus (as triple superphosphate). In this biomass harvest, only no fence, no fertilizer (NFCT); small mesh fence, no fertilizer (SFCT); no fence, N plus P (NFNP); and small mesh fence, N plus P (SFNP) treatments were sampled in 2006.
Shaver, G.R. and F.S. Chapin, III. 1991. Production/biomass relationships and element cycling in contrasting arctic vegetation types. Ecological Monographs 61: 1-31.
Calculations: Tissue mass data are expressed in g/quadrat (400 cm2). Multiply by 25 to get g/m2.
Biomass quadrats, size 20 x 20 cm, were taken from treatment. Four quadrats were randomly located along transect lines in each of the replicate blocks of each treatment. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. Quadrats were sorted within 24 hours into species and then into tissue type. The samples were dried at 50-70 degrees C in a drying oven and after several days weighed to the nearest milligram. Samples were lumped by block and subsequently ground in a Wiley Mill and analyzed for percent C and N using a Perkin-Elmer CHN analyzer (Series 2400).
If no samples were present in the biomass data, zeros are used. If no samples were analyzed for %C and %N, decimal points were used as place holders.
Version 2: Upadte LTERNET Data Access server proxy link for Excel and comma delimited data files. Changed from knb to das in url.
Version 3: Updated to eml 2.1; changed date format to dd-mon-yy and moved seedling information to commnets. Jim L 22May12
Version 4: Taxonomic coverage data updated. Updated metadata to newer form (with sites sheet). CH March 2013
Version 5: Checked keywords against the LTER network preferred list and replaced non-preferred terms. Jim L 27Jan14
Version 6: Changed Distribution URL since the LTER network DAS system is being discontinued. JimL 9Apr2015
Updated the treatment names to the all biomass file; recalculated the averages and std err. Jim L Oct2017