Name:
North American Northern Boreal Woodland Macrogroup
Reference:
NatureServe Biotics 2019
Description:
This macrogroup occurs through northern Manitoba, northeastern Saskatchewan, southern Nunavut, the Northwest Territories, northern Alberta, northeastern British Columbia, northern Yukon Territory and interior Alaska. It is characterized by the prevalence of open-canopied stands of short-statured <i>Picea mariana</i> and <i>Picea glauca</i>. The latter species is more common west of the Canadian Shield on the relatively nutrient-rich glacial deposits of northern Northwest Territories and Yukon Territory. Near the northern limit of the range, woodlands become even more sparse and are interspersed with tundra toward latitudinal and elevational treeline. Permafrost-affected terrain, developed in thick moss layers and dominated by stunted black spruce stands, is widespread on level landscapes and on northern aspects of upland slopes; active (i.e., freeze/thaw) permafrost layers are typically less than a meter deep. The understory is usually low in stature, sparse and shrubby, under which lichens often form nearly continuous carpets. Vascular understory species include dwarf <i>Salix</i> spp. and <i>Betula nana</i>, as well as ericaceous species such as <i>Ledum groenlandicum, Ledum palustre, Vaccinium uliginosum, Vaccinium vitis-idaea</i>, and <i>Empetrum nigrum</i>. Important terricolous lichens include <i>Cladonia</i> spp., <i>Stereocaulon</i> spp., <i>Nephroma arcticum, Peltigera</i> spp., and <i>Cetraria</i> spp. This macrogroup is influenced by continental and cordilleran climates with extremely cold winters and short cool summers that limit tree growth and understory development; less precipitation towards the north also reduces the extent and depth of organic terrain. The eastern portion of the described range (i.e., between Hudson Bay and Great Slave Lake) is underlain by the Canadian Shield; west of Great Slave Lake the lithology is sedimentary, providing greater nutrient status to soils. All portions of the range were glaciated, except a small Beringean area along the Yukon - Alaska border. This macrogroup is differentiated from ~West-Central North American Boreal Forest & Woodland Macrogroup (M496)$$ to the south by the lack of broad-leaved deciduous trees and the prevalence of spruce woodlands on well-drained sites, as well as the significant occurrence of diagnostic indicator species such as <i>Ledum palustre, Vaccinium uliginosum</i>, and <i>Nephroma arcticum</i>.
Accession Code:
urn:lsid:vegbank.org:commConcept:40538-{1DE3794B-7478-4B0B-800B-D01BA2E9CD20}
Plot-observations of this Community Concept:
0
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