Laserfiche WebLink
Given the significant lack of precipitation during the spring and growing season of 2002, <br />• vegetation cover correspondingly decreased. Vegetation cover at the Osgood sand <br />reference azea decreased 53.7 percent from 2001, the largest decrease of the azeas <br />sampled. Decreases in vegetation cover at the reclamation areas ranged from 39.9 percent <br />(1997 reclamation areas) to 52.2 percent at the 1995 reclamation, with the 1998 <br />reclamation areas showing a 41.6 percent decrease. <br />Mean total vegetation cover was relatively consistent this season ranging from 22.60 <br />percent (Osgood sand reference azea) to 29.80 percent (1998 reseed/interseeded azeas). <br />This result is not unexpected given the fact that the 1998 areas had been previously seeded <br />to the permanent revegetation mix and some mature growth had already developed. <br />HERBACEOUS PRODUCTION <br />Total herbaceous production was more variable overall than vegetation cover during the <br />2002 growing season (Table 11). Mean herbaceous production ranged from 26.28 g/mZ <br />(Osgood sand reference area) to 79.08 g/m2 (1998 reseed/interseeded azeas). All azeas <br />showed a significant decrease in herbaceous production over 2001 production values, <br />ranging from 57.6 percent (1998 reseed/interseeded areas) to 78.0 percent in the Osgood <br />sand reference azea. With the exception of the 1998 reseed/interseeded areas the <br />percentage of decrease between azeas was consistent. <br />Perennial grasses dominated total herbaceous production in all azeas sampled this year <br />• accounting for between 54.2 percent (1997 reclamation azeas) and 85.2 percent (Osgood <br />sand reference azea) of the total herbaceous production. Annual grasses did not <br />contribute significantly to herbaceous production this year, lazgely due to the lack of eazly <br />season precipitation, retazding growth of Bromus tectorum. Annual and perennial forbs <br />contributed significantly also this yeaz, with total production of all forbs ranging from 10.9 <br />percent in the 1995 reclamation areas to 45.1 percent in the 1997 reclamation areas. Forb <br />representation was aided by the persistence and growth of Kochia scoparia in the adverse <br />conditions. <br />SPECIES COMPOSITION <br />The Colorado Division of Minerals and Geology considers species composition of the <br />revegetated and reclaimed azeas to be an indicator of successfiil vegetation establishment <br />and a diverse vegetation community. A standard has been set by CDMG for the <br />evaluation of species composition at the Keenesburg Mine. To be judged successful, at <br />final bond release, this standazd requires that, "the species composition on the reclaimed <br />area is such that there aze at least seven perennial species of which four aze warm season <br />grasses and one is a forb. No one component of the above species should comprise <br />greater than 40% relative importance nor less than 3% relative importance. Relative <br />importance will be measured by calculating relative cover of the revegetation species. <br />Vegetation species which may be used in the calculation of species composition may be <br />any plant species not defined as a noxious or prohibited plant species, and may be native <br />or introduced." <br />Coors Energy Company Page t7 <br />2002 Revegetation Monitoring Report <br />