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2.2.2 Vegetation Cover <br />• Vegetation cover was estimated by the use of the point-intercept method. An ocular point <br />frame (ESCO Associates) was used to minimize instrument error and maximize precision <br />and observer accuracy. Cover transects were 25 meters in length, with two sample data <br />points collected at 1.0 meter intervals along the transect on opposite sides of the transect <br />centerline, 1.5m apart. Transect direction was established randomly through the use of <br />computer generated random directions (0-360°). In no event were transects allowed to <br />extend within ten feet of reference or revegetated area boundaries to minimize impacts from <br />"edge effect." <br />For statistical purposes, each cover transect (comprising 50 data points) served as a sample <br />unit. Data points recorded the first vertical "hit" on vegetation (above or below the <br />instrument), soil (bare ground), rock, litter, or cryptogamic crust. Subsequent "hits" on <br />vegetation were also recorded. Cover data were recorded and reported by individual plant <br />species. The first interception was used to calculate total vegetation cover values. Additional <br />interceptions were used to calculate relative cover of individual plant species and lifeforms. <br />The quantitative cover data also provided the basis for calculation of species composition and <br />relative importance. <br />2.2.3 Herbaceous Production <br />Herbaceous production was estimated by the harvest method. One herbaceous production <br />• plot was located and randomly oriented at the origin of each cover transect. Additional <br />production plots were randomly located. Herbaceous production plots were 0.50 square <br />meters in area. All current year above ground live herbaceous plant biomass was clipped <br />within the 0.50 square meter quadrat. Production material was air dried until weights varied <br />by no more than 0.1 g. <br />2.2.4 Species Composition <br />Species composition information was derived from quantitative vegetation cover data. <br />Relative cover information provided a basis for evaluation of the importance of each <br />encountered plant species and lifeform and for comparison to the final revegetation success <br />criterion. The tables presenting data summaries for total vegetation cover for each area <br />sampled also contain the relative cover by species, and a column depicting the numerical <br />ranking of each species by relative cover within the area. <br />2.3 SAMPLE NUMBERS/SAMPLE ADEQUACY <br />For the purposes of this study, total vegetation cover and total herbaceous production <br />sampling were undertaken to sample adequacy for each sampling unit. Parameter testing <br />occurred at the one-sided 90% confidence level. Comparisons between sample mean <br />parameter values and the revegetation success standard assume that the sample mean value <br />• accurately represents the population mean in all cases. <br />Coors Energy Company Keenesburg Mine Page 7 <br />2007 Phase 111 Vegetation Study