Name:
Abies lasiocarpa - Picea engelmannii / Streptopus amplexifolius Swamp Forest
Reference:
NatureServe Biotics 2019
Description:
This is a very broadly distributed association occurring in the major ranges of northern Utah, Wyoming, Idaho, eastern Washington and Montana into at least west-central Alberta. In drier climates it is a small-patch type, but with higher precipitation regimes; it can expand to large patches in valley locations. Elevations range from 1250 m in the north to 3355 m at the highest in the south. In the southern portion of this type's distribution, parent materials are largely alluvium, soils are loamy to silty in texture, derived from the local country rock, which ranges from sandstone to basalt to granitics in the vicinity of major batholiths. In the north, sedimentary and metasediments are the rule with silty clay loams and loams predominating. Mottling and rust pockets are found in many soil pits, indicating high water tables or subirrigation for a portion of the year. Subirrigation is reflected by landscape positions on lower terraces and stringers of lower order streams, toeslopes and side-hill seeps. Most of the indicator forbs present are associated with the decidedly rich end of the soil-nutrient regime. The canopy for the most part is open, the modal cover ranging between 40-60%, dominated by <i>Abies lasiocarpa</i> and <i>Picea engelmannii</i>. <i>Pinus contorta</i> is the major seral species in the middle Rockies, whereas in the northern Rockies <i>Pseudotsuga menziesii, Larix occidentalis, Pinus monticola</i>, and <i>Abies grandis</i> are additional seral species. The dominant aspect of the undergrowth is an abundance of medium to tall forbs, though shrub cover can at times approach 50%; shrubs are a more important component in the northern distribution of the association. Shrubs with the highest constancy and cover include <i>Ribes lacustre, Vaccinium membranaceum, Alnus viridis ssp. sinuata, Lonicera utahensis, Cornus sericea</i>, and <i>Menziesia ferruginea</i>. The graminoid component is negligible. Of the forbs diagnostic for the association four, <i>Streptopus amplexifolius, Senecio triangularis, Heracleum maximum</i> and <i>Mitella pentandra</i>, are distributed across the breadth of the type, though there are numerous ancillary high-constancy forbs spanning the type's range including <i>Thalictrum occidentale, Geranium richardsonii, Osmorhiza berteroi, Maianthemum stellatum, Orthilia secunda</i>, and <i>Arnica cordifolia</i> (or <i>Arnica latifolia</i> at higher elevations). <i>Aconitum columbianum, Saxifraga odontoloma, Mertensia ciliata</i>, and <i>Mertensia arizonica</i> are wet-site taxa occurring with relatively high constancy in the southerly portion of the association. The forb component of diagnostic species is more diverse from central Idaho northward.
Accession Code:
urn:lsid:vegbank.org:commConcept:29245-{B8185F1E-40C1-4A4C-A05A-194933D6AFFD}
Plot-observations of this Community Concept:
18
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