which tends to be dominated by tall forbs rather than 

 by grasses. The POTR/SYOR/BRCA c.t. is relatively 

 good range for cattle and somewhat less desirable for 

 sheep because of the prominence of grasses. The absence 

 of a tall shrub stratum and somewhat meager stratum of 

 low shrubs restricts the value of this type as wildlife 

 habitat. 



This specific serai community type has not been 

 reported elsewhere. However, it is believed to represent 

 a grazing-degraded type leading to a POTR/SYOR/SESE 

 climax community type, which appears rather wide- 

 spread. Communities similar to POTR/SYOR/SESE type 

 occur in southeastern Idaho (Mueggler and Campbell 

 1982), western Wyoming (Youngblood and Mueggler 

 1981), and western Colorado (Hoffman and Alexander 

 1980, 1983). 



Populus trem uloides/Sym ph oricarpos 

 oreophilus/Poa pratensis Community 

 Type (POTR/SYOR/POPR c.t.) 



We identified the POTR/SYOR/POPR c.t. on the basis 

 of 30 sampled stands widely scattered from the Bear 

 River Range in extreme northern Utah to the Abajo 

 Mountains in the southeast and the high plateaus in 

 southwestern Utah. The stands were at elevations as low 

 as 6,000 ft (1 830 m) in northern Utah, but were between 

 7,500 and 8,800 ft (2 290 and 2 680 m) in southern Utah. 

 These stands generally occupied shallow slopes, a wide 

 variety of exposures, and grew on all soils except those 

 derived from granitic parent material. 



The vegetation appears considerably degraded by abu- 

 sive grazing. Althcugh a wide variety of species may be 

 encountered in different stands within this type, few are 

 constant, much less prominent. The vegetation of the 

 type is characterized by the presence of a low shrub 

 layer dominated by Symphoricarpos oreophilus and an 

 herb layer comprised predominantly of Poa pratensis 

 and Taraxacum officinale. Most frequently associated 

 with these are Berberis repens, Agropyron trachycaulum, 

 Achillea millefolium, and Lupinus argenteus. 



The type is a result of a long history of intensive graz- 

 ing of what probably once were cUmax POTR/SYOR/ 

 CAGE or POTR/SYOR/SESE community types. 

 Although both P. pratensis and T. officinale are palata- 

 ble to cattle and sheep, their growth characteristics 

 enable them to withstand intensive grazing remarkably 

 well. These two species are able to increase under abu- 

 sive grazing because of reduced competition from the 

 more grazihg-sensitive species that are equally or even 

 less palatable to livestock. Continued abusive grazing 

 probably will cause depletion of S. oreophilus and con- 

 version to a POTR/POPR c.t. 



Overall productivity of both trees and undergrowth in 

 this type appears low to moderate. Tree basal area, all 

 aspen, ranged from 96 to 160 ft^/acre (22.0 to 36.7 m^/ha) 

 and averaged 117 ft^'/acre (26.9 m-/ha). Aspen site index 

 at 80 years ranged from 43 to 50 ft (13.1 to 15.2 m) and 

 averaged 47 ft (14.2 m). Aspen reproduction in the sam- 

 pled stands averaged a low 890 suckers/acre (2 200/ha); 

 two-thirds of these were in the 1- to 4.6-ft (0.3- to 1.4-m) 

 size class. 



Undergrowth production ranged from 426 to 1,240 

 lb/acre (479 to 1 391 kg/ha) and averaged a low to 

 moderate 929 lb/acre (1 042 kg/ha). This was equally dis- 

 tributed among shrubs, forbs, and graminoids. Only 30 

 percent of the undergrowth was rated as desirable; 65 

 percent was rated as intermediate forage suitability. 

 Presumably this community type, degraded by abusive 

 livestock grazing, was once considerably more produc- 

 tive of forage than at present. Both overall production 

 and species diversity have undoubtedly decreased. Value 

 of the type as wildlife habitat appears only moderate 

 because of limited structural and low species diversity. 



This grazing-induced type is similar to the 

 P. tremuloides/S. oreophilus-P. pratensis serai type in 

 southeastern Idaho reported by Mueggler and Campbell 

 (1982). 



Populus tremuloides/Juniperus communis/ 

 Astragalus miser Community Type 

 (POTR/JUCO/ASMI c.t.) 



The POTR/JUCO/ASMI c.t. is a minor and fairly local 

 type that was observed only in the Uinta Mountains of 

 northern Utah. We sampled 10 stands, primarily on 

 easterly and southerly exposures, at relatively high ele- 

 vations ranging from 8,300 to 9,300 ft (2 530 to 2 830 m). 

 The stands were restricted to sedimentary soils derived 

 from quartzite, sandstone, and limestone parent 

 material. 



The vegetation of this type can have considerable spe- 

 cies diversity. Occasional conifers may be present, par- 

 ticularly Pinus contorta, but they are never abundant. A 

 pronounced low shrub layer is present, usually consist- 

 ing of a mixture in which Juniperus communis is a con- 

 stant and usually dominant or codominant species. The 

 shrubs Symphoricarpos oreophilus and Berberis repens 

 frequently occur; in some stands Arctostaphylos uva-ursi 

 or Artemisia tridentata may be abundant. The herb stra- 

 tum is typified by the relative abundance of Astragalus 

 miser. Other frequently encountered forbs include 

 Achillea millefolium, Taraxacum officinale, and 

 Antennaria microphylla. Graminoids usually are fairly 

 scarce, with Agropyron trachycaulum, Leucopoa kingii, 

 and Bromus ciliatus most frequently present. 



Judging from the usual abundance of A. miser, 



A. millefolium, and T. officinale, this appears to be a 

 serai type created by overgrazing. Occupancy of rela- 

 tively dry sites and similarities in species composition 

 suggest that the type may be a degraded version of the 

 POTR/JUCO/CAGE c.t. Stands within the type suscepti- 

 ble to Abies lasiocarpa invasion may be serai and 

 grazing-altered communities within the A. lasiocarpa/ 



B. repens or A. lasiocarpa/J. communis habitat types 

 described by Mauk and Henderson (1984). 



This type was not sampled for production. However, 

 its successional relationship to the POTR/JUCO/CAGE 

 c.t. suggests that wood productivity is probably fairly 

 low with an aspen site index at 80 years less than 46 ft 

 (14 m). Average undergrowth productivity is also proba- 

 bly quite low, less than 580 lb/acre (650 kg/ha). This 

 undergrowth consists of a high proportion of species 

 that are intermediate to low in forage suitability. The 



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