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• fraction in those plots where they occurred. Shrubs were not clipped. Clipped samples <br />were oven dried at 100 degrees centigrade for 24 hours, and were then weighed to the <br />nearest one-hundredth of a gram. The data were summarized by calculating mean pro- <br />duction per square meter and the percent of total biomass for each species. <br />Shrub Density Data Collection. Shrub density data were collected in the reference <br />and affected areas using a belt transect method. All the shrubs occurring within ten Im <br />by 50m belt transects were counted and assigned to one of the following height classes: <br />Class I, 0.10-0.25 meters; Class II, 0.26-0.75 meters; and Class III, 0.76-1.50 meters. <br />None of the shrubs were taller than 1.5 meters. The shrub data were summarized by <br />calculating frequency and mean density for each species and mean total density for all <br />species. In The summary tables, density is expressed on the basis of number of individuals <br />per hectare and number per acre. <br />Species Lists. Separate species lists were prepared for the tie across haul road and <br />for the mixed sagebrush reference area. Observations on species composition were made <br />in early June and also in mid-July. <br />• <br />RESULTS <br />Tie Across Haul Road <br />The native vegetation studied along the realigned tie across haul road is dominated <br />by a mixed sagebrush shrubland vegetation type. The major species is big sagebrush <br />(Artemisia tridentata), however it occurs in the area as two relatively distinct sub- <br />species. Mountain big sagebrush (Artemisia tridentata ssp. vaseyana) and Rothrock big <br />sagebrush (Artemisia tridentata ssp. rothrockii) are both prevalent within the area. IT is <br />because of the mixture of these two species that the type is called a mixed sagebrush <br />shrubland. The most obvious difference between the two sagebrush subspecies is their <br />height. Rothrock big sagebrush Tends to be short and mat-like while mountain big sage- <br />brush tends to be somewhat taller and grows as an erect shrub. None of the shrubs on the <br />site are taller than 1.5 meters. <br />On the basis of the cover sampling data, the major species were Rothrock big <br />• sagebrush (10.8 percent mean cover; 70 percent frequency), mountain big sagebrush (3.7 <br />percent mean cover; 50 percent frequency), arrowleaf balsamroot (Balsamorhiza <br />