Common (Translated Scientific) Name: Sitka Alder / Common Ladyfern - Drooping Woodreed Wet Shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association is found in cool and moist mountainous regions between about 1022-1837 m (3350-6012 feet) elevation, ranging from northern California, along the eastern slope of the Cascades to southern British Columbia, through northeastern Oregon, Washington and Montana and north into the Canadian Rockies. It usually occurs as narrow stringers in moderate to steep, V-shaped valleys in areas of deep or long-lasting snowpacks. Such habitats include floodplains and streambanks of small streams (orders 1 and 2), avalanche chutes, and occasionally springs. These areas often flood during snowmelt and remain wet throughout the summer. Soils vary, but are typically thin silt or sandy loams over alluvial cobble and gravel. Alnus viridis ssp. sinuata forms dense, 3- to 5-m tall thickets with 60 to nearly 100% cover, but less dense stands are also known. Conifers, especially Abies grandis and Picea engelmannii, are sometimes present and may indicate a successional trend toward conifer-dominated associations. Periodic severe flood or avalanche disturbance may be necessary for maintaining the long-term dominance of Alnus viridis ssp. sinuata. The only understory shrubs with greater than 50% constancy (but usually low cover), are Ribes spp. (Ribes hudsonianum or Ribes lacustre), Salix drummondiana, and Rubus parviflorus. Athyrium filix-femina, 30-90 cm tall, is always present in the understory, typically with 20-80% cover, while another fern, Gymnocarpium dryopteris, is sometimes subdominant. Cinna latifolia is often present, but averages only 5% cover (and less than Athyrium filix-femina). Tall forbs, most commonly Maianthemum stellatum, Senecio triangularis, Chamerion angustifolium, Prosartes spp., and Streptopus amplexifolius, have high constancy but usually have less than 10% cover, although they can occasionally be quite abundant, with as much as 50% canopy cover. A lush ground layer composed of species including, but not limited to, Boykinia major, Circaea alpina, Claytonia cordifolia, Galium triflorum, and Mitella spp., is often present beneath the taller Athyrium filix-femina canopy.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is defined as a PNV vegetation type. If it were renamed as a dominance type, the species would include Alnus viridis ssp. sinuata and Ribes hudsonianum (RIHU). This association is a well-documented type known from 64 quantitative plots: 14 plots sampled in northeastern Oregon (Crowe and Clausnitzer 1997, Crowe et al. 2002), approximately 38 plots from eastern Washington (Wooten and Morrison 1995, Kovalchik 2001, WNHP 2002), and 12 plots in central and northern Idaho (IDCDC 2002). Several plots included in the more general Alnus viridis ssp. sinuata community type sampled by Hansen et al. (1995) in northwestern Montana are likely synonymous with this association. Stands are known from Glacier National Park, Montana, but the total number of occurrences is not known (MTNHP 2002a). Cinna latifolia is not present in this community in Montana and rarely has over 10% cover in stands throughout its range. In stands with sparsely vegetated understories, Athyrium filix-femina can have low cover, but it remains the dominant understory species. The following three associations are similar but have yet to be incorporated into the National Vegetation Classification. The related, but distinct Alnus viridis ssp. sinuata / Cinna latifolia (Crowe and Clausnitzer 1997, Crowe et al. 2002) and Alnus viridis ssp. sinuata / Gymnocarpium dryopteris (Kovalchik 2001), which are distinguished by having 100% constancy and moderate cover of their respective diagnostic understory species, but only trace to low cover of Athyrium filix-femina. The Alnus viridis ssp. sinuata / Rubus spectabilis / Athyrium filix-femina association (Diaz and Mellon 1996, Murray 2000, Kovalchik 2001) apparently ranges from the eastern slope of the Cascades west to the Pacific coast and is distinguished by having moderate to high cover and constancy of Rubus spectabilis. If Oplopanax horridus is present with moderate cover, the stand is classified as ~Alnus viridis ssp. sinuata / Oplopanax horridus Shrub Swamp (CEGL001157)$$ (Kovalchik 2001). [SVC sees very little, if any, environmental distinction between ALNVIR/ATHFIL and ALNVIR/MESIC and only the slightest compositional distinction, mostly ATHFIL present with modest cover or not; this may be the case for trying to adopt a type defined elsewhere to local circumstances; recognizing both types does no real "harm," but it is probably an inconsequential distinction.]

Similar NVC Types: No Data Available

note: No Data Available