Common (Translated Scientific) Name: Subalpine Fir - Engelmann Spruce / Bride''s Bonnet Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association is broadly distributed across the inland northwest and northern Rocky Mountains, where it is associated with a maritime component of climate. It occurs as far east as the Continental Divide in northwestern Montana and Alberta, extending only a few air miles to the east of this strongest of topographic breaks. This community occupies relatively moist (mesic) and cool sites having free air drainage and lacking frost pocket conditions. Elevations range from 1066 to 1710 m (3500-5600 feet). It occurs on slopes of all degrees of steepness and aspect orientation, though it is more likely to occur from toeslope through midslope positions (predominantly collecting positions). At the dry extremes of its distribution it is more strongly associated with protected positions such as concave slopes, moist depressions in gently sloping plateaus, stringers along perennial stream bottoms, toeslopes and northeastern aspects. It occurs on a variety of parent materials, as varying as granite, limestone, glacial-fluvial material, and volcanic ash caps. Abies lasiocarpa and Picea engelmannii dominate the tree canopy. The most important seral species are Pseudotsuga menziesii, Larix occidentalis, and Pinus contorta, however, their cover seldom exceeds 10-15%. Total tree canopy cover is generally in excess of 55% ranging to 75%. Abies lasiocarpa dominates the tree regeneration layer, whereas Picea engelmannii reproduction is more sporadic. The shrub layer ranges from low diversity and cover to extremely diverse and high in cover; the shrubs present are judged largely seral. Those of highest constancy include Acer glabrum, Ribes lacustre, Lonicera utahensis, Rubus parviflorus, Symphoricarpos albus, and Vaccinium membranaceum. The low-shrub component is well-represented by Linnaea borealis, Spiraea betulifolia, Paxistima myrsinites, and, in the northern portion of the type''s range, Vaccinium myrtillus. The only graminoids consistently present are Bromus vulgaris and Calamagrostis rubescens; the latter species may be relatively abundant on early seral stands but with an increase in tree canopy cover it is less abundant. The forb component is relatively species-rich and abundant; cover of the diagnostic species Clintonia uniflora or Tiarella trifoliata generally does not exceed 20%. There are many other forbs with high constancy and the potential to have appreciable cover, including Maianthemum stellatum, Arnica cordifolia, Thalictrum occidentale, and Eucephalus engelmannii; forbs merely with high constancy include Orthilia secunda, Galium triflorum, Goodyera oblongifolia, Osmorhiza berteroi, and Viola orbiculata.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is essentially a renamed (including Picea engelmannii) subset of the Abies lasiocarpa / Clintonia uniflora Habitat Type, Clintonia uniflora Phase (Pfister et al. 1977, Cooper et al. 1987) or the similarly named climax plant association (Johnson and Simon 1987, Williams et al. 1995). It is a subset because previous authors have used Abies lasiocarpa as an indicator species (present and reproducing successfully or having some minimum amount of cover, e.g., 10% (Williams et al. 1995)) which creates a very broad category, capable of being dominated by any number of seral tree species. The type concept used here is that Picea engelmannii or Abies lasiocarpa must have a substantial presence (at least 10% canopy cover, one or both species) but need not be dominant. This interpretation then allows for recognition of stands dominated by seral tree species that occur within this moderate portion of the subalpine zone, as distinct plant associations. The undergrowth concept for the type was kept intact, recognizing the broadest interpretation of Cooper et al. (1987) that either Clintonia uniflora or Tiarella trifoliata need be present and not confined to microsites within the stand for type recognition. This approach essentially recognizes the Clintonia uniflora Phase of Abies lasiocarpa / Clintonia uniflora Habitat Type (Pfister et al. 1977, Cooper et al. 1987), but with other phases split off (note one exception below) as associations unto themselves (e.g., ~Abies lasiocarpa - Picea engelmannii / Menziesia ferruginea / Clintonia uniflora Forest (CEGL005893)$$), it would be redundant to append another Clintonia uniflora to the name. The Aralia nudicaulis Phase was combined with the Clintonia uniflora Phase because after examining data from many stands a considerable overlap was found between the two phases and the unique habitat (rich benchlands) once claimed for the Aralia nudicaulis Phase was not substantiated. Furthermore the Aralia nudicaulis Phase was absent from sites that appeared in all respects to be quintessential habitat, adding doubt to its consistency as an indicator. The existence of this type in the vicinity of the Cascade Crest needs exploration.

Similar NVC Types: No Data Available

note: No Data Available