combination of low productivity and low suitability 

 makes this type poor livestock range. For similar rea- 

 sons, plus limited structural diversity, the type probably 

 provides relatively poor wildlife habitat. 



Aspen communities with a low shrub layer dominated 

 by J. communis have been reported for Wyoming 

 (Youngblood and Mueggler 1981; Wirsing and Alexander 

 1975), but none have herbaceous undergrowth similar to 

 this Utah type. 



Populus trem uloides/Vera trum 

 californicum Community Type 

 (POTR/VECA c.t.) 



This is a scarce yet identifiably unique community 

 type. We sampled only two stands, one on the north 

 slope of the Uintas in the upper Bear River drainage and 

 the other in the San Pitch Mountains east of Santaquin. 

 These stands occupied moist sites on heavy, deep soils 

 with poor moisture drainage. 



The type is readily recognized by an undergrowth 

 dominated by Veratrum californicum. a tall, coarse forb. 

 Shrubs are either absent or occur in only trace amounts, 

 thus the vegetation is structurally simple. Associated 

 herbaceous species are those that grow well under fairly 

 moist site conditions, such as Carex hoodii, Phleum 

 alpinum, and Rudbeckia occidentalis. 



This appears to represent a climax community type or 

 habitat type. Heavy grazing probably results in an 

 increase in V. californicum and i?. occidentalis at the 

 expense of the more palatable graminoids. 



The single stand sampled for productivity within this 

 type suggests that although tree basal area may be low, 

 aspen growth is rapid on these moist sites. Tree basal 

 area in the stand was 71 ft-/acre (16.4 m^/ha) and aspen 

 site index at 80 years was 70 ft (21.3 m). Aspen 

 reproduction was a moderate 2,300 suckers/acre 

 (5 700/ha), two-thirds of which were in the 1- to 4.6-ft 

 (0.3- to 1.4-m) size class. 



Undergrowth production can be high because lack of 

 soil moisture seldom restricts plant growth. The sampled 

 stand produced 1,582 lb/acre (1 775 kg/ha). Forbs 

 accounted for 34 percent of this, graminoids 65 percent, 

 and shrubs only 1 percent. The type is not very good for 

 livestock grazing because of species composition. 

 Although our sample indicates that 59 percent of the 

 undergrowth consists of vegetation in the desirable and 

 intermediate forage suitability classes, this can be mis- 

 leading when applied to all stands within the type. 

 Veratrum californicum has the potential to exclusively 

 dominate the undergrowth on some sites. When this 

 occurs, the undergrowth has little value as livestock for- 

 age. Lack of structural and species diversity limits the 

 value of this type as wildlife habitat. 



Although scarce, this type is fairly widespread. Hoffman 

 and Alexander (1980) described a P. tremuloides/ 

 Veratrum tenuipetalum habitat type on the Routt 

 National Forest in northwestern Colorado, which is also 

 restricted to wet sites. According to Harrington (1954), 

 V. tenuipetalum and V. californicum are synonymous. 



Populus tremuloides/Heracleum lanatum 

 Community Type (POTR/HELA c.t.) 



Although not encountered frequently, representatives 

 of the POTR/HELA c.t. were found from the Bear River 

 Range in extreme northern Utah southward to the 

 Fishlake Plateau in central Utah. We sampled 14 stands 

 that generally occupied fairly shallow slopes on northerly 

 and easterly exposures. The type was primarily on soils 

 derived from sandstone, but it also occurred on hme- 

 stone, quartzite, and volcanics. Elevations ranged from 

 approximately 7,000 to 9,300 ft (2 130 to 2 830 m). These 

 sites were fairly moist but not as moist as those 

 occupied by the POTR/VECA c.t. 



The vegetation in this type consists of only two dis- 

 tinct strata: the aspen overstory and a diverse herba- 

 ceous undergrowth. Occasional shrubs, primarily 

 Symphoricarpos oreophilus and Sambucus racemosa, 

 may be present but are never abundant. The under- 

 growth usually is dominated by a mixture of tall- 

 growing forbs of which Heracleum lanatum is a conspic- 

 uous constant and usually abundant typifying species 

 (fig. 5). Other forbs frequently prominent in this type 

 include Rudbeckia occidentalis, Senecio serra, 

 Polemonium folio si ssimum, Mertensia arizonica, 

 Valeriana occidentalis. and Delphinium occidentale. Fre- 

 quent and sometimes abundant grasses include Bromus 

 carinatus and Elymus glaucus. 



This appears to represent a fairly moist, climax com- 

 munity type. Many of the tall forbs found in the type, 

 and especially H. lanatum. are palatable to both sheep 

 and cattle. Abusive grazing by either class of hvestock 

 probably will result in a decrease of H. lanatum and 

 other palatable forbs with an accompanying increase in 

 R. occidentalis, Vicia americana, Lathyrus spp.. and pos- 

 sibly S. serra. Continued abuse would tend to eliminate 

 the palatable perennials and encourage occupancy by 

 such annuals as Nemophila breviflora and Galium 

 bi folium. 



Tree productivity on this relatively moist site varies 

 widely but is usually high. Basal area ranged from 87 

 to 283 ft-/acre (19.9 to 65.1 m'/ha|, and averaged 

 183 ft-/acre (42 m^/ha). This consisted almost entirely of 

 aspen. Site index for aspen at 80 years ranged from 45 

 to 78 ft (13.7 to 23.8 m) and averaged 65 ft (19.9 m). 

 Aspen reproduction within these mature stands varied 

 widely but was generally high, averaging almost 5,600 

 suckers/acre (13 900/ha), three-fourths of which were in 

 the 1- to 4.6-ft (0.3- to 1.4-m) height class. 



Undergrowth production generally is high and domi- 

 nated by forbs, many of which are palatable to livestock. 

 Production ranged from 956 to 1,692 lb/acre (1 083 to 

 1 899 kg/ha) and averaged 1,228 lb/acre (1 378 kg/ha). 

 Over three-fourths of this production consisted of forbs 

 and the remainder was divided between graminoids and 

 shrubs. Of the undergrowth, 85 percent fell into the 

 desirable and intermediate forage suitability classes. The 

 type is considered good summer range for livestock, par- 

 ticularly for sheep, but of only moderate value as wild- 

 hfe habitat because of relatively low structural diversity. 



22 



