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• 0.8918 to 0.9431) for the reclamation areas and reference azea respectively. The form of <br />the predictive equations vaned from those predicting total vegetation cover. The <br />predictive equations for total herbaceous production were concave in appearance, <br />originating with a ]ow rate of biomass accumulation and accelerating through increasing <br />levels of precipitation. Additionally, the third order approximation for the reference area <br />revealed an inflection point at low levels of precipitation. While this phenomenon may be <br />related to unmeasured biomass production by woody plants, this was not observed in the <br />field nor corroborated by sampling. For this reason, the predictive equation for the <br />reference area for total herbaceous production was dismissed from firrther consideration <br />as a revegetation success criterion. <br />Table A2 (updated in the Amendmern for 2002-2004 data) was employed to evaluate the <br />significant species components (species composition) of both the Osgood Sand Reference <br />Area and the reclamation azeas. A review of species consistently contributing to total <br />cover at the Osgood Sand Reference Area revealed that one woody shrub (Artemesia <br />filifolia), three native warm season grasses (Artdropogon hallii, Bouteloua gracilis, and <br />Calamovilfa longifolia), and one cool season grass (Stipa viridula) were the only <br />consistent core contributors of three percent or more relative cover over the period of <br />record. <br />3.2 2002-2004 RESULTS <br />• 3.2.1 Osgood Sand Reference Area <br />3.2.1.1 Total Vegetation Cover <br />Figures AI through A3 present plots of Osgood Sand Reference Area total vegetation <br />cover and September-July precipitation for the yeazs subsequent to the data set contained <br />in the 2002 investigation. Each subsequent plot adds one year of cover and precipitation <br />data and portrays the accompanying best-fit curve with corresponding equation and <br />correlation coefficient. <br />In the case of total vegetation cover at the Osgood Sand Reference Area from 2002 to <br />2004 a quadratic equation (either second or third order) best represented the correlation <br />between total vegetation cover and September-July precipitation As was the case in the <br />2002, the best-fit form of the predictive equations for the reference azea with the inclusion <br />of the 2002-2004 data was that of a convex quadratic equation originating with a rapid <br />rate of growth, progressing to a decreasing rate of overall increase in cover, and ending <br />asymptotically (or with a slight decrease) at the highest level of precipitation encountered <br />in the data set. <br />With the addition of data from 2002 forwazd, a genera( decrease in the correlation <br />coefficient has been noted from 0.9279 in 2002 to 0.9039 in 2003 to 0.8116 in 2004. <br />u <br />Coors Energy Company Keeneaburg Mine Page 5 <br />2005 Addendum to Reviabn aF Revegetation Success Crkeria <br />