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<br />Total estimated shrub density on this sample unit was .72 stems/50 m2 (Table I). Densi- <br />ties on a per acre and per hectare basis were 59 and 144 respectively. Species contribut- <br />ing the highest densities were rubber rabbitbrush (Chrysothamnus nauseosus) at 54.1 <br />percent and big sagebrush at 25 percent of all shrubs sampled. Other shrubs present <br />include skunkbrush sumac (Rhus irilobata) (9.7 percent), Gambel oak (5.6 percent), and <br />mountain snowberry (5.6 percent}. Shrub heights ranged from a mean low of 10.0 cm for <br />skunkbush sumac to a mean high of 63.6 cm for rubber rabbitbrush. The skunkbrush <br />sumac establishment may have been the result of an early shrub planting program since it <br />is not a commonly occurring shrub in the area. Records were unavailable to confirm this. <br />Graded Spoils/Direct Haul Topsoil (Area D) <br />Approximately 304 acres were sampled in this unit, the largest of the three units <br />sampled. This included areas that have had direct haul topsoil replaced on graded spoils <br />from 1977 to the present. Many areas of this unit received upper lifts of topsoil that <br />contained seed, roots, and plant residues. These areas are generally in the southern part <br />(i.e., most recently reclaimed) of the sample unit. <br />Fifty iransects were located and sampled in this unit. One sample site in the original <br />study plan was found to be in a disturbed area when field sampling took place. An addi- <br />tional transect had been selected during study design and was subsequently sampled <br />during the field season. <br />Shrub density estimated in the sample unit (Table I) was 8.70 stems/50 m2 or 1756 <br />stems/hectare (706 stems/acre). Highest densities were contributed by big sagebrush <br />(55.2 percent) and mountain snowberry (35.6 percent). Other shrubs present were com- <br />mon chokecherry (4.8 percent), Woods rose (2.1 percent), Saskatoon serviceberry (1.4 <br />percent), Douglas rabbitbrush at 0.7 percent, and Gambel oak at 0.2 percent. Shrub <br />heights ranged from a mean low of 9.9 centimeters for mountain snowberry to a mean <br />high of 41.0 centimeters for Saskatoon serviceberry. <br />Graded Spoils/Topsoil From Stockpiles (Area T) <br />This unit of the study area included those areas of graded spoils that were reclaimed <br />during the period of 1972 to 1981. Topsoil placed on these graded spoil areas came from <br />topsoil stockpiles. Verification as to the actual length of time topsoil remained in these <br />-5- <br />