habitat. Early successional stages are of intermediate 

 value to wildlife. This value decreases as succession pro- 

 ceeds to conifer dominance. 



Although not identified by the same name, communi- 

 ties similar to this serai type can also be found in Idaho 

 and adjacent Wyoming. Some of the stands used to 

 describe the P. tremuloides-A. lasiocarpa/Thalictrum 

 fendleri type in southeastern Idaho (Mueggler and 

 Campbell 1982) resemble those in our Utah type, except 

 for fewer tall forbs. In Utah, the type is regarded as a 

 successional stage within the A. lasiocarpa/Osmorhiza 

 chilensis habitat type. Steele and others (1983) show 

 P. tremuloides as a major serai tree in this habitat type 

 in eastern Idaho and western Wyoming. 



Populus tremuloides-Abies lasiocarpa/ 

 Carex geyeri Community Type 

 (POTR-ABLA/CAGE c,t.) 



This community tv'pe is fairly common on the high 

 plateaus and mountains of central and southern Utah, 

 although it is found occasionally in northern Utah, prin- 

 cipally in the Uinta Mountains. It is a relatively high 

 elevation type. Over 80 percent of the 77 stands sampled 

 were at elevations over 9,000 ft (2 740 m). These stands 

 most frequently occupied rather gentle slopes, and 

 exposures of the slopes did not appear important. Over 

 three-fourths of the stands occurred on soils derived 

 from either volcanic or granitic parent material. 



The conspicuous presence of Abies lasiocarpa in the 

 tree stratum clearly reflects this type's successional sta- 

 tus. Picea engelmannii is also frequently present in the 

 tree layer. The undergrowth is chairacterized by the 

 absence of a distinct shrub layer and the lack of minimal 

 representation by the tall forb and tall grass group of 

 species. The shrubs Juniperus communis, Berberis 

 repens, and Symphoricarpos oreophilus occasionally may 

 be present but are never abundant. Consequently the 

 undergrowth consists primarily of low herbaceous 

 growth. This usually is composed of such graminoids as 

 Carex rossii, Stipa occidentalis, and Carex geyeri, and 



such forbs as Fragaria vesca. Astragalus miser, Achillea 

 millefolium, and Trifolium longipes. Even though 

 C. geyeri has low constancy, it is used in the type name 

 to reflect this particular herbaceous complex for nomen- 

 clature consistency. This undergrowth is similar to that 

 in the POTR/CAGE c.t. except for the constancy differ- 

 ences between C. geyeri and C. rossii, which are consid- 

 ered approximate ecological equivalents (see the 

 POTR/SYOR/CAGE c.t. section). Carex geyeri is encoun- 

 tered most frequently in northern Utah, whereas the 

 POTR-ABLA/CAGE type occurs most frequently in cen- 

 tral and southern Utah. 



The POTR-ABLA/CAGE c.t. is a seral stage within 

 the A. lasiocarpa forest series (fig. 14), probably within 

 the central and southern Utah A. lasiocarpa/C. rossii 

 habitat type (Youngblood and Mauk 1985), judging from 

 undergrowth similarities. The related habitat type for 

 stands in northern Utah is uncertain. 



Heavy grazing within the type leads to further sim- 

 plification of what is basically rather species-poor under- 

 growth composition. Grazing tends to favor the domi- 

 nance of such grazing-resistant species as A. miser, 

 F. vesca, and T. longipes. 



This is a good type for the production of trees and a 

 poor type for the production of undergrowth. Tree 

 growth was measured on 36 stands within the type. 

 Basal area ranged from 93 to 320 ft^/acre (21.3 to 

 73.4 m^/ha) and averaged 199 ft^/acre (45.6 m^/ha). This 

 was the highest average basal area for any of the com- 

 munity types we encountered. Conifers constituted 20 

 percent of the basal area. Aspen site index at 80 years 

 ranged from 25 to 64 ft (7.6 to 19.5 m) and averaged a 

 modest 48 ft (14.8 m). Aspen reproduction in these 

 stands averaged a moderate 1,300 suckers/acre 

 (3 300/ha), of which about a fourth were in the large 1- to 

 4.6-ft (0.3- to 1.4-m) size class. Conifer seedlings, 90 per- 

 cent of which were A. lasiocarpa, averaged approxi- 

 mately 1,400 stems/acre (3 400/ha). About half of these 

 were in the large size class. 



Production of undergrowth on 31 stands averaged a 

 low 271 lb/acre (304 kg/ha). Almost two-thirds of this 



Figure 14.— 7"/ie Populus 

 tremuloides-Abies 

 lasiocarpa/Carex geyeri c.t., 

 common on the high 

 plateaus of central and 

 southern Utah, is a seral 

 aspen type successional to 

 A. lasiocarpa or Picea 

 engelmannii forests, or both. 

 Herbaceous undergrowth is 

 usually sparse and consists 

 of such species as Carex 

 rossii, Astragalus miser, 

 Fragaria vesca, and 

 Trifolium longipes, as in this 

 stand on the Aquarius 

 Plateau, Dixie National 

 Forest. 



35 



