and on the steep, northerly slopes below the crest. It occurs 

 above the elevational limits of Pseudotsuqa roenziesii . Adjacent 

 warmer sites generally support either Abies las iocarpa / Clematis 

 Columbiana or Abies las iocarpa / Arnica cordif olia . At the crest 

 of the Pryors, ABILAS/RIBMON groves alternate with more exposed 

 sites supporting Festuca idahoensis grasslands. 



Vegetation- Abies lasiocarpa and Picea enqelmannii co-dominate 

 the overstory. Pinus contorta and Pseudotsuqa menziesii are 

 absent. In addition to Ribes montiqenum , characteristic 

 undergrowth species include Arnica cordif olia , Galium boreale, 

 Pyrola secunda , and Clematis columbiana (the later in stands 

 intergrading to Abies las iocarpa / Clematis columbiana ) . Bryophyte 

 cover may exceed 30% of the ground surface and soil lichen cover 

 may exceed 3%. 



Soils- Soils underlying the ABILAS/RIBMON type are derived from a 

 variety of parent materials. Ground surfaces generally have 

 little bare soil and rock cover of 10% or less. The soil 

 subgroup at our single soil characterization site was a Typic 

 Cryoboroll. The single pH measurement was 6.2, and conductivity 

 was 142 uhmos/cm- (1 stand). 



Other Studies- This type has been previously described in the 

 Pryor Mountains, the Centennial Mountains, and the Gravelly Range 

 of Montana by Pfister et al, (1977) . Similar communities occur 

 in Colorado, Idaho, Utah, and Wyoming (Bourgeron and Engelking 

 1992) . 



Natural Heritage Program Rank- G5/S4 



4. Abies las iocarpa / Vaccinium scoparium c.t. 



(ABILAS/VACSCO; subalpine fir/grouse whortleberry) 



(1 Stand) 



Environment- This is one of the most abundant forest vegetation 

 types in Montana but is relatively uncommon within the study 

 area. It was found on cold, gentle slopes and ridges above 8,000 

 feet. Adjacent sites on calcareous parent materials that are 

 topographically similar often support Abies las iocarpa / Arnica 

 cordif olia . 



Vegetation- Abies lasiocarpa and Picea enqelmannii co-dominate 

 the overstory. Pinus contorta is usually present. The 

 undergrowth is dominated by a low shrub layer of Vaccinium 

 scoparium . Most other species in the undergrowth have less than 

 2% cover. Arnica cordif olia cover sometime equals or exceeds 

 20%. Bryophyte cover often exceeds 20% of the ground surface. 



Soils- Soils underlying the ABILAS/VACSCO type are usually 

 derived from non-calcareous parent materials. Ground surfaces 



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