Table 3.— Vegetation key to aspen community types (c.t.) in Utah, where Populus tremuloides constitutes at least 50 percent of 

 the tree canopy 



Note: The "tall forb group" referred to in this key consists of the following species: 



Agastache urticifolia Polemonium foliosissimum 



Aster engelmannii Rudbeckia occidentalis 



Delphinium occidentale Scroptiularia tanceolata 



Mertensia arizonica Senecio serra 



Osmorliiza occidentalis Valeriana occidentalis 



Note: Adjective descriptors: 



trace = less than 1% cover 



scarce, present, readily apparent = 1% to 4% cover 

 conspicuous = 5% or greater cover 

 prominent = 10% or greater cover 



Key to cover types: 



I. Abies lasiocarpa and/or Picea engelmannii at least 5% 



canopy cover Populus tremuloides-Abies lasiocarpa (Go to B) 



I. A. lasiocarpa and/or P. engelmannii less than 5% 



cover II 



II. Abies concolor and/or Picea pungens at least 10% 



canopy cover Populus tremuloides-Abies concolor {Go to 0) 



II. A. concolor and/or P. pungens less than 10% 



cover Ill 



III. Pseudotsuga menziesii at least 10% canopy cover Populus tremuloides-Pseudotsuga menziesii (Go to 



D) 



III. P. menziesii less than 10% cover IV 



IV. Pinus ponderosa at least 5% canopy cover Populus tremuloides-Pinus ponderosa (Go to E) 



IV. P. ponderosa less than 5% cover V 



V. Pinus contorta at least 10% canopy cover Populus tremuloides-Pinus contorta (Go to F) 



V. P. contorta less than 10% cover VI 



VI. Some other coniferous trees at least 10% canopy cover Unclassified cover type 



VI. Not as above Populus tremuloides (Go to A) 



Key to community types: 



A. (Populus tremuloides cover type) 



1. Prunus virginiana, Amelanchier ainifolia. or Acer 



grandidentatum (alone or in combination) prominent, generally 



exceeding 10% canopy cover Tall shrub group (Go to AA) 



1. Above-named shrubs totaling less than 10% cover 2 



2. Symphoricaropos oreophilus prominent with at least 

 10% canopy cover, or Juniperus communis and/or 

 Artemisia tridentata conspicuous with at least 5% 

 combined cover, or Sambucus racemosa and/or 



Sambucus cerulea with at least 5% cover Low shrub group (Go to AB) 



2. Not as above Herb group (Go to AC) 



AA. (Tall shrub undergrowth type) 



1., Pteridium aquilinum conspicuous with at least 5% cover: 



usually dominates herbaceous layer Populus tremuloides/Acer grandidentatum/ 



Pteridium aquilinum c.t. (p. 13) 

 1. P. aquilinum absent, or present in only trace amounts 2 



2. One or more members of the tall forb group readily 

 apparent, or Bromus carinatus and/or Elymus glaucus. 

 alone or in combination usually forming a conspicuous part 



of herbaceous layer Populus tremuloides/Prunus virginiana/Senecio 



serra c.t. (p. 14 ) 



2. Neither tall forbs nor B. carinatus or E. glaucus 



conspicuous 3 



3. Carex geyeri, Carex rossii, and/or Stipa occidentalis 



conspicuous Populus tremuloides/Prunus virginiana/Carex geyeri 



c.t. (p. 15) 



3. Not as above Unclassified type 



(con.) 



9 



