Four to five quadrats (20cm x 20cm squares) located randomly along a line near each of four blocks of 15N plots were destructively measured for species biomass (g/m2) and net primary production (g m-2 yr-1). Harvest times, June 26-28 1992, August 8-13 1992 and 2-6 July 1993, coincided with the times of 15N plant and soil harvests (see McKane, et al).

Calculations: Units; Tissue mass data are expressed in g/quadrat (400 cm2). Multiply by 25 to get g/m2.

Reference Citations: McKane, R. B., L. C. Johnson, G. R. Shaver, K. J. Nadelhoffer , E. B. Rastetter, B. Fry. A. E. Giblin, K. Kielland, B. L. Kwiatkowski, J. A. Laundre, and G. Murray. 2002. Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra. Nature, 415:68-71 .
Shaver, G. R., and F. S. Chapin. 1991. Production biomass relationships and element cycling in contrasting arctic vegetation types. Ecological Monographs 61:1-31.

Sampling Description.

Quadrats, 20x20 cm, were collected and sorted into species and then into tissue type. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. 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, belowground rhizomes, etc. In most cases only the only belowground tissues measured are rhizomes and stems. The samples are dried at 50-70 degrees C and weighed to the nearest milligram. Samples are returned to Woods Hole for nutrient analysis. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.)