Created: 2014-02-03 13:52:35
Modified: 2014-02-03 13:57:18
DESCRIPTION OF AREA CONTAINING SITE:
Site description: Well-developed water-track complex, southeast-facing slope (4 degrees); moist and wet acidic shrublands.
Vegetation communities: (1) Interwater track areas: Moist Betula nana, Rubus chamaemorus, Hylocomium spendens low-shrub tundra. (2) Water tracks: Wet Salix pulchra, Eriophorum angustifolium, Sphagnum spp. low-shrub tundra. (3) Transitional areas to water tracks: Wet Salix pulchra, Betula nana, Rubus chamaemorus, Petasites frigidus, Carex bigelowii, Sphagnum spp. low-shrub tundra. Cover of top 5 species: Betula nana (27%), Hylocomium (20%), Salix pulchra (12%), Carex bigelowii (11%), Eriophorum vaginatum (5%)
Mean vegetation height: 13.8 +/- 14.0 cm
Mean live moss layer thickness: 3.2 +/- 1.1 cm
Organic layer thickness: 19 + 0.9 cm.
(Walker and Bockheim, 1995)
SAMPLING DESIGN AND METHOD:
Beginning in 1995, the active layer has been probed at least annually at the site. The procedure involves pushing a metal rod, calibrated in cm, to the point of refusal, interpreted in most cases to be the frost table. Thaw depth measurements at each site were obtained by probing at 5 m intervals along the plot’s two perpendicular and one diagonal transect, resulting in 71 points per plot per probing date.
In 1995 the site was instrumented with several OnsetTM portable data loggers connected to probe-type thermistors. Each logger/thermistor system has an effective temperature range of -50oC to +33oC and resolution of approximately 0.32oC. At each site, one thermistor was placed in a radiation shield approximately 2 m above the ground surface, and nine loggers were placed at the interface between mineral soil and organic material in various microtopographic positions within the site. Temperature measurements were collected at, 1 hr, and 2 hr intervals depending on season, and year. Details on methodology are provided in Klene et. al 2001.
CALM USA George Washington University
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