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Noxious Weeds <br />• Of plant species observed during 1996 sampling, none are listed state-wide as a noxious weed <br />(Thornton et al., 1974). Pennycress (Thlasoi arvense) is a restricted noxious weed in <br />Colorado (Thornton et al., 1974). Pennycress is a common species in the youngest reclaimed <br />areas, and disappears within a few years. <br />Climatic Conditions <br />Precipitation data by month from the nearby Seneca II Mine for 1991, 1992, 1993, 1994, <br />1995, and 1996, as well as the 10-year average for the mine are shown in Figures is and tb. <br />As can be seen in those graphs, 1996 precipitation declined from above normal conditions of <br />1995 to closer to normal. January and February were above average with below average <br />amounts in March and July of 1996. <br />When examined from the standpoint of what climatic indices seemed to have correlated most <br />closely with vegetation response at the nearby Seneca II Mine, it has appeared that the Total <br />Precipitation for the Previous 6 months (Figure 3) or the Total Precipitation for the Previous <br />4 Months (Figure 4) were better predictors than the Total Precipitation for the Previous 12 <br />Months (Figure 2). Both Figures 3 and 4 showed that 1995 was greatly superior to other years <br />• in suggested moisture availability and this corresponds to the extremely high levels of <br />vegetation growth that were observed in 1995. 1996 shows up as somewhat less favorable <br />(previous 6 months, Figure 3) or considerably less favorable (previous 4 months, Figure 4). <br />Figure 5 indicates that 1996 was a warmer year than 1995, with total degree days about as <br />much above average as 1995 was below average. This additional warmth would have tended to <br />exaggerate any deficiency in moisture. <br /> <br />8 <br />