Plant Association Information
Picea mariana/Eriophorum vaginatum plant association (Black spruce/tussock cottongrass)
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The Picea mariana/Eriophorum vaginatum plant association is dominated by Picea mariana and occasionally Picea glauca in the overstory with cover reaching 20% and a height ranging from 1.5 to 6.0 meters (Appendix 4). Tussocks of Eriophorum vaginatum dominate the understory with cover values reaching 80%, and tussock height averaging 20 centimeters. Ledum decumbens or L. groenlandicum also has significant cover (50%) in some sites. Additional species include Vaccinium uliginosum, Betula glandulosa, Betula nana and Salix bebbiana. Mosses, such as Hylocomium splendens and Sphagnum fuscum, exceed 30% cover on some sites.
This plant association is common on level (up to 2 degrees) slopes of floodplains, terraces and ice-core hills within the boreal forest predominantly on the north side of the Alaska Range. The elevation ranges from 339 to 700 meters. The tussocks average 20 centimeters tall and the hollows contain water during wet periods. Soils are mesic and have a layer of peat, averaging 25 centimeters deep, over a thin layer of mineral soil. Permafrost is reached at a depth of 25 to 50 centimeters. The one-pH value measures 7.0.Associated Plant Species: Betula nana
, Eriophorum vaginatum
, Hylocomium splendens
, Picea glauca
, Picea mariana
, Rhododendron groenlandicum
, Rhododendron tomentosum ssp. decumbens
, Salix bebbiana
, Vaccinium uliginosum