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C1981019, TR84 Adequacy No. 2 response <br />April 8, 2011 <br />Colowyo's Response: <br />Roy Karo (Peabody/Seneca/Yoast/etc.) was contacted prior to the last submittal. He has recent <br />and local experience with planting young aspen saplings. His experience has been that you <br />should expect about 50% mortality of the planted saplings within two years. This is why <br />Colowyo volunteered to do supplemental planting in year two of the trail to try to account for <br />this. The text has been amended to change "should" to "will" as requested. <br />7. Page 4.15-13, bullet lg - The planting configuration of one aspen row (five feet wide) followed <br />by a Sagebrush Steppe mix (17 feet wide) follows the format of aspen studies at Seneca Coal <br />Company Yoast and IIW mines. These studies examined the effects of landscape fabric and <br />irrigation in the survival of aspen and serviceberry but do not address the goal of these field <br />trials, which is creating wildlife habitat. Aspens tend to grow in stands or groves rather than <br />rows. The Division suggests that the planting interval be changed to 4 rows of aspen plantings <br />(4*5' band = 20' aspen band) followed by 4 bands of Sagebrush Steppe mix (4* 17' band = 68' <br />band Sagebrush Steppe mix). This new pattern does not require additional materials or labor but <br />can increase moisture retention in the aspen band by having a larger contiguous surface area <br />covered by Weedguard, reduce edge effects of weed competition and better mimics the pattern <br />of an actual aspen grove. The weed barrier will need to be removed in the third year to allow the <br />growth of aspen shoots. After the Weedguard is removed, a seed mix containing native grasses <br />and forbs (no shrubs) needs to be planted to hinder the invasion of annual invasive species. This <br />seed mix needs to be designed and consist of species that are common to the understory of the <br />aspen grove reference areas. <br />Colowyo's Response: <br />Colowyo is attempting to lay the groundwork for the evolution of these field trials into a <br />beneficial area for wildlife. Utilizing a single strip of weedguard fabric has been shown to <br />increase surviveabilty of plantings, which is the first step to creating this type of specialized <br />habitat. Colowyo has not been made aware of any documented benefit of multiple strip vs. <br />single strip application of weedguard fabric in Northwest Colorado. The practical rationale for <br />not incorporating the Division's suggested changes to the trial configuration is tied mainly to <br />hydrologic stability if/when these practices are applied to much steeper slopes. Aspen is a <br />clonal species that spreads mainly through suckering, and most stands are essentially comprised <br />of one individual. The grass species chosen for inclusion in the mix are appropriate and <br />compatible with the purposes of these trials, and for the most part are species that have a track <br />record of being successful at Coloywo. Removal of the weedguard fabric has not been discussed <br />prior to this communication and additional discussions need to occur before Colowyo will <br />commit to this additional step, as it would create renewed disturbance, an avenue for <br />competition for the plantings, and potential implications for bond release within the 10 year <br />liability period. In addition, as the pre-mine lithology no longer exists in this location or any <br />other mined previously at Colowyo, it may be prudent to leave the fabric in place as a means to <br />ensure somewhat elevated levels ofplant available water in the soil. <br />8. Page 4.15-13, bullet li -It is stated "that the requirement for 50% of the required 375 shrubs in <br />this area be big sagebrush." Please reference where in the Colowyo permit (CO-1981-019) that