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C1981019, TR84 Adequacy No. 2 response 2 April 8, 2011 <br />3. Page 4.15-13, bullet lc -It is stated "Approximately 48 inches of topsoil will be placed to <br />replicate common topsoil depth conditions..." Please change the topsoil replacement depth to <br />"at least 48 inches" which better replicates the conditions in the undisturbed areas, and to <br />incorporate the concept of significant variation in soil thickness that would be applied within the <br />South Taylor area. Also make the appropriate changes to Page 4.15-14, bullet 2c. <br />Colowyo's Response: <br />Text amended as requested. <br />4. Page 4.15-13, bullet le - Colowyo has committed to planting commercially available 2-3 foot <br />containerized aspen stock for planting purposes from the most similar source elevation available <br />in the area. Research indicates that the larger the containerized aspen and native shrubs are the <br />better their chances are for survival. The Division recommends that Colowyo use 1 gallon or <br />larger containerized aspen, with at least 10% being 5 gallon containerized trees. <br />Colowyo's Response: <br />Granted that larger transplants have a greater rate of survival, however, they have a <br />disproportionately higher cost. Seedlings that are 2-3 feet tall will average $8-10 each (just for <br />the stock, not the planting). ]-gallon stock will likely be in the $30 range, and 5-gallon stock <br />will likely be in the $80-120 range. Therefore, assuming a 50% mortality rate as found at <br />Peabody, a simple cost-benefit analysis indicates that it would be more economical to plant 3 X <br />as many 2-3 foot stock rather than 1-gallon stock, and IOX as many 2-3 foot stock as 5-gallon <br />stock. It would also be more economical to plant more of the smaller stock than anything larger <br />given the manual labor necessary for transplanting. Therefore, a modest improvement in <br />survival does not warrant the disproportionately high extra cost for larger stock. <br />Page 4.15-13, bullet le - It is stated "a number of (300) live aspen plants within the trial during <br />2016 will be considered a successful demonstration..." Please reference CDOW or DRMS <br />literature that supports the standard of 300 stems/acre as being an adequate density. Also include <br />the area units being measured, i.e. stems/acre. Also make the appropriate changes to page 4.15- <br />14, bullet 2e and page 4.15-16, bullet 3e. <br />Colowyo's Response: <br />The baseline surveys of aspen density in the Collom area(recent data) showed an average <br />density of 242.8 trees per acre. The Aspen reference area (at much higher elevation showed an <br />average density of 402 trees per acre. Therefore documentation of 300 surviving trees per acre <br />falls well within this range and therefore could be considered "successful ". The bullets have <br />been amended to include a supplemental planting threshold level of surviving plantings at less <br />than 350 stems/acre during 2012 monitoring. <br />6. Page 4.15-13, bullet le - It is stated "Supplemental planting of aspen should be initiated in year <br />2012 should survival of the 2011 plantings be very low." Please change first should to will. <br />Also, very low is a subjective phrase and needs clarification. Please reference CDOW literature, <br />applicable studies or DRMS rules documenting at what mortality rate supplemental aspen <br />planting will be initiated. Also make the appropriate changes to page 4.15-14, bullet 2e and page <br />4.15-16, bullet 3e.