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<br />maple (Ater p/abruml and gooseberry (Ribes inermel. As is typical of aspen in western
<br />• Colorado, the native perennial forbs lifeform is relatively abundant end diverse. The fifty-one
<br />species encountered comprised a total of 12.2 percent of total vegetation cover. Species
<br />contributing the largest amounts to total cover were western yarrow (Achi//ea /anu/osal,
<br />nettleleaf gainthyssop /Agastache urticifo/ial, white-flower peavine /Lathyrus /eucanthusl,
<br />chiming bells (Mertensia ci/fatal, western aniseroot (Osmorhiza occidenta/isl, black-eyed Susan
<br />/Rudbeckia amp/a1, meadow-rue (Tha/icfrum fend/eri/, edible valerian (Va/eriana edu/isl, and
<br />American vetch (Vicia americans). Native perennial cool season grasses comprised 8.0 percent
<br />of total vegetation cover. Introduced perennial forbs were very sparse, accounting for only 0.6
<br />percent of total vegetation cover. Of this total the bulk was comprised of elk sedge ICarex
<br />9eyeril, blue wildrye /E/ymus g/aucusl, and Agassiz bluegrass (Poo agassizensisl. Other
<br />common native perennial cool season grasses included onion-grass /Brome/ica spectabi/isl,
<br />Porter brome /Bromopsis porteril, slender wheatgrass IE/ymus irachycau/us ssp. irachycau/usl,
<br />and fowl bluegrass (Poo pa/ustris/. Introduced perennial cool season grasses were sparse,
<br />being mostly confined to a few stands where horses or other livestock may have been
<br />quartered and fed with hay from meadows planted to European species. Annual forbs were
<br />relatively sparse; introduced annual forbs accounted for 0.3 percent of total vegetation cover,
<br />while native annual forbs totaled 0.5 percent of total vegetation cover.
<br />Total vegetation cover in the portion of the Aspen Forest type to be affected by mining
<br />• (Appendix 10-tOA, Table 10A-11 was 88.5 percent, while standing dead, litter, bare soil, and
<br />rock were 1.2, 7.6, 2.5, and 0.1 percents, respectively. By comparison, in the unaffected
<br />(extended reference) area portion of the Aspen Forest vegetation type (Appendix 10-10A, Table
<br />t0A-21. total vegetation cover was 91.5 percent, while standing dead, litter, bare soil, and
<br />rock were 0.9, 4.6, 2.8, and 0.0 percents, respectively. Species density in the Aspen Forest
<br />effected areas was 35.1 species per 100 sq. m., while in the extended reference areas, it was
<br />40.1 species per 100 sq.m.
<br />Herbaceous biomass production averaged 837 pounds oven-dry per acre in the affected area
<br />(Appendix 10-1OA, Table 10A-31 and 771 pounds oven-dry per acre in the extended reference
<br />area (Appendix 10-10A, Table t0A-4). Although the moisture in 1997 was abundant, and
<br />aspen forest understory plants give the impression of verdancy and abundance, the limited
<br />amount of available light restrains the levels of biomass production possible under even the
<br />best conditions.
<br />Shrub density in the Aspen Forest vegetation type affected area averaged 9,251 stems per acre
<br />(Appendix 10A, Table 10A-51 with over half this directly attributable to mountain snowberry
<br />and most of the remainder to Saskatoon serviceberry and black chokecherry. These
<br />proportions were closely reflected in the data from the extended reference area where shrub
<br />• density averaged 9,818 stems per acre (Appendix 10A, Table 10A-61. Live tree stem density in
<br />this type averaged 317 stems per acre in the affected area (Appendix 10A, Table 10A-7) and
<br />53 Revised 9198
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