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Revegetation Success Criteria <br />Separate reference areas of approximately 3 acres in size were established for the two <br />vegetation communities: piiion juniper and grassland. However, these reference areas <br />cannot be located currently and were unable to be utilized for comparison purposes <br />during the 2002 sampling period. Therefore, the data collected in 2002 will be compazed <br />to the average of the data collected at the reference areas in 1981, obtained from the <br />revegetation plan from the permit submitted October 16, 1981. <br />According to the data collected in 1981: <br />- Total cover on the grassland reference area was 35.5 percent. The standard deviation <br />was 8.91. Average stem density was 4955 stems per acre (or 1.22 stems per mz), and <br />production was 49.11 pounds per acre (or 1.375 grams per quarter mz). <br />- Total cover on the Piiion-Juniper reference area was 10.1 percent. The standazd <br />deviation was 2.92. Average stem density was 2546 stems per acre (or 6.29 stems per <br />mz), and production was 8.82 pounds per acre (or .247 grams per quazter mz). <br />- Therefore, the new vegetation standazds will be: <br />- 22.8 percent average total vegetation cover <br />- 3750.5 stems per acre (or .926 stems per mz) <br />- and 28.97 pounds of production per acre (or 3.24 grams per mz) <br />These revegetation standazds are based on weighted averages between grassland and <br />Piiion-Juniper reference aeeas. However, given the inability to locate these reference <br />areas, success standards have been revised to a technical standazd that has also taken the <br />baseline data collected in 1981 into consideration. <br />Sample Numbers/Sample Adequacy <br />Sample adequacy calculations were made for vegetative cover of the sampled reclaimed <br />azea. The following formula, accepted by the CDMG, was used for these calculations: <br />z z <br />nmin ' t S <br />(d Xnar)z <br />where <br />n,„;° =minimum sample size <br />t =the "T" distribution value at the 90% confidence level <br />s =sample standazd deviation <br />sz =sample variance <br />d =percent acceptable deviation from the mean (10%) <br />X~ =sample mean <br />