22 percent graminoids. Of the undergrowth cover, 95 

 percent comprised species considered either desirable (55 

 percent) or intermediately desirable (40 percent) forage 

 plants. Thus, this type is relatively good livestock range 

 and provides good wildlife habitat because of its great 

 amount of structural diversity. 



Communities similar to the POTR/PRVI/SESE c.t. are 

 widely encountered in surrounding States. The 

 P. tremuloides/A. alnifolia-S. oreophilus c.t. described by 

 Mueggler and Campbell (1982) for southeastern Idaho 

 contains stands similar to our type. Hoffman and 

 Alexander (1980) described a P. tremuloides/S. oreophilus 

 habitat type in northwestern Colorado that apparently 

 includes stands similar to our POTR/PRVI/SESE c.t.; 

 about half of the stands within their type have a tall 

 shrub component of P. virginiana or A. alnifolia or both, 

 a low shrub stratum of S. oreophilus, and an herbaceous 

 layer fairly similar to that in our type. Bunin (1975) 

 described a P. tremuloides/Quercus gambelii— 

 A. alnifolia-Thalictrum fendleri association on the west 

 slope of the Park Range in Colorado that is similar 

 except for the absence of Q. gambelii in our stands. In 

 addition, a P. tremuloides/S. oreophilus community with 

 similar tall shrub, low shrub, and tall herbaceous species 

 was observed in northeastern Nevada (Lewis 1975). 



Populus tremuloides/Prunus 

 virginiana/Carex geyeri Community 

 Type (POTR/PRVI/CAGE c.t.) 



The POTR/PRVI/CAGE c.t. is a minor type that is 

 most prevalent in northern Utah. We sampled 12 stands 

 along the Bear River Mountains, southward along the 

 Wasatch Range, and intermittently eastward along the 

 south slope of the Uinta Mountains. A single stand was 

 in the Pine Valley Mountains in extreme southwestern 

 Utah and one in the Abajo Mountains of southeastern 

 Utah, which reflects its infrequent but wide distribution. 

 The stand in the Abajo Mountains was of questionable 

 placement in this community type. The sampled stands 

 occurred at elevations between 5,500 and 8,700 ft (1 680 

 and 2 650 m) and did not appear restricted by slope 

 exposure or soil parent material. 



The vegetation in this type reflects a somewhat drier 

 environment than either the POTR/PRVI/SESE or 

 POTR/ACGR/PTAQ c.t.'s, the other two tall shrub 

 undergrowth types within this cover type 

 group. Although a variety of conifers may be present, 

 none are abundant. The stands within this community 

 type are structurally diverse with multiple layers of 

 vegetation. Below the aspen overstory exists a tall shrub 

 component in which Amelanchier alnifolia or Prunus 

 virginiana or both usually predominate; occasionally 

 Acer grandidentatum is a major part of this layer. A low 

 shrub layer is usually conspicuous with an abundance of 

 Symphoricarpos oreophilus and often substantial 

 amounts of Berberis repens, Pachistima myrsinites, and 

 Rosa woodsii. The herbaceous layer is characterized by 

 an abundance of the graminoids Carex geyeri or Stipa 

 occidentalis or both. Species and amounts of forbs vary 

 appreciably but can include considerable amounts of 

 Thalictrum fendleri, Smilacina stellata, Geranium 



viscosissimum, Achillea millefolium, and occasionally 

 Lupinus argenteus. 



This is primarily a climax community type. In some 

 cases, however, with active invasion of Abies lasiocarpa, 

 stands classified in this type might represent serai com- 

 munities in the A. lasiocarpa/B. repens habitat type if in 

 northern Utah (Mauk and Henderson 1984) or in the 

 A. lasiocarpa/C. geyeri habitat type if in central or south- 

 ern Utah (Youngblood and Mauk 1985), judging from 

 species similarity in the undergrowth. Abusive livestock 

 grazing in this type may lead to composition changes 

 that favor Poa pratensis. Astragalus miser, A. millefolium, 

 and possibly Lathyrus spp. 



The potential for wood fiber production on this minor 

 type appears fairly low. Basal area of trees on seven 

 sampled stands ranged from 71 to 155 ft^/acre (16.2 to 

 35.7 m^/ha), and averaged 104 ft^/acre (23.8 m'-^/ha). 

 About 98 percent of this basal area was aspen, and 

 2 percent was conifers. Site index for the aspen at 80 

 years ranged from 34 to 62 ft (10.4 to 18.9 m) and aver- 

 aged 46 ft (14.1 m). Aspen reproduction in these mature 

 stands varied greatly, averaging 2,200/acre (5 500/ha). 

 About a third of these were suckers less than 12 inches 

 (3 dm) high and the remainder were in the 1- to 4.6-ft 

 (0.3- to 1.4-m) height class. 



The undergrowth appears somewhat better suited for 

 cattle than for sheep grazing. Overall productivity is 

 moderate, and forage suitability appears generally good. 

 Current annual growth ranged between 609 and 1,838 

 lb/acre (684 and 2 062 kg/ha) and averaged 975 lb/acre 

 (1 094 kg/ha). This growth consisted of 46 percent tall 

 and low shrubs, 25 percent forbs, and 29 percent grami- 

 noids. Over 95 percent of the undergrowth cover con- 

 sisted of plants with at least intermediate suitability as 

 livestock forage. Therefore, overall forage production is 

 fairly good. The type has relatively high value as wildlife 

 habitat because of the great amount of structural diver- 

 sity contributed by the abundant tall and low shrubs. 



Types similar to the POTR/PRVI/CAGE c.t. have been 

 noted in southeastern Idaho and in western Wyoming. 

 Mueggler and Campbell (1982) defined a P. tremuloides/ 

 A. alnifolia-Calamagrostis rubescens c.t. in Idaho, and 

 Youngblood and Mueggler (1981) a P. tremuloides/ 

 P. virginiana c.t. in Wyoming that structurally and com- 

 positionally resembles the Utah type. In both the Idaho 

 and Wyoming types, however, C. rubescens is abundant 

 in the herbaceous layer rather than the C. geyeri or 

 S. occidentalis or both that are present in the Utah type. 



Populus tremuloides/Samhucus racemosa 

 Community Type (POTR/SARA c.t.) 



Although this is a relatively minor community type, 

 it is fairly well distributed over the higher mountains of 

 Utah. The 16 stands sampled occurred primarily on the 

 Wasatch-Cache, Uinta, and Manti-LaSal National 

 Forests. The type appeared most frequently on midslope 

 to upper-slope positions on sedimentary soils. All but 

 one of the stands occurred at elevations exceeding 

 8,000 ft (2 440 m). Half the stands grew at elevations 

 over 9,000 ft (2 740 m). 



Abies lasiocarpa and Picea engelmannii occasionally 

 are found in this type but never in abundance. Sambucus 



15 



