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<br />Of!211H <br /> <br />ENVIRONMENTAL CONSEQUENCES <br />In order to assess the potential impacts on vegetation resources, the SUP area was sub-divided into numerous <br />polygons, and required treatment prescriptions (if any) were determined for each polygon. In addition, to quantify <br />potentially increasing degrees of change to the forest habitat resulting from tree removal in affected polygons, <br />clearing (glading) of forested vegetation types was categorized as low (5-15 percmt clearing), medium (16-40 <br />percent clearing), or high (>40 percent clearing) levels of tree removal. <br /> <br />Swmmary <br /> <br />For the No Action Alternative, construction of previously approved developments would not involve large areas <br />of vegetation disturbance since it would consist mainly of the removal or replacement of existing lifts. No known <br />populations of brownie lady slipper or other species of concern would be impacted. <br /> <br />Under Alternative B, about 925 acres (16 percent of the analysis area) would be affected, but 90 percent of this <br />would be either skied over (no alteration of existing vegetation), receive low intensity giading (less than 15 <br />pen;ent tree removal), or avalanche damaged trees would be removed. Medium or high intensity giading would <br />affect about 76 acres while construction of lifts and catwalks/access roads would affect another 33 acres. The <br />main impacts 00 each vegetation type would consist of the following (proportion of medium/high intensity and <br />line clearing is shown in parentheses): Mixed conifer, 399 acres (21 percmt); potential spruce/fir and lodgepole <br />recruitment old growth, 104 acres (43 per~nt); and aspen, 72 acres (15 perceot). In addition, 74 acres of <br />sensitive alpine tundra (80 pen;ent of the tola! area of this type) could be affected during times of low snow cover. <br />Eighty acres of mountain brush and 17 acres of montane willow could be affected by low intensity giading. No <br />known populations of brownie lady slipper would be impacted although rather extensive areas of potential <br />habitats do occur on north and north-east facing slopes. Proposed use of existing fall-lines and natural sid <br />corridors decreases the probability of causing adverse impacts on potential habitats. <br /> <br />Impacts to vegetation under Alternative C would approximate those under Alternative B except that impacts to <br />vegetation in Maroon Bowl would be eliminated and those due to the Ridge Surface Lift would be added. A total <br />of 683 acres of vegetation would be affected. Total effects by vegetation type are as follows (percent of <br />mediwn/high intensity and line clearing is shown in parentheses): Mixed conifer, 358 acres (24 percent); poteotial <br />recruitment old growth, 104 acres (43 percent); aspen, 76 acres (20 percent); mountain brush, 27 acres; and <br />montane willow. 5 acres. While the affected area of alpine tundra would be 21 acres less than under Alternative <br />B, where this habitat is affected, the impact would be greater due to grading requirements along part of the <br />ridgeline for the installation of the Ridge Surface Lift. The impact on brownie lady slipper habitat would likely <br />be similar under both Alternatives B and C although exclusion of the Steeplechase Catwalk under Alternative <br />C could somewhat reduce the impact on potential habitat for this species. <br /> <br />POTENTIAL MITIGATION MEASURES <br />A vegetation management plan specifically designed for Aspen Highlands conditions will be developed prior to <br />commencement of any construction or developmeot activities. In particular, clearing of vegetation and soil <br />disturbance should be limited along catwalks and lift lines and terminals and Forest Service BMPs will be adhered <br />to where clearing is necessary. In addition, guidelines for tree removal in avalanche starting zones specified under <br />the Human Health and Safety section below will be adhered to. Only native species, obtained from certified <br />weed-free seed sources, will be used to revegelate disturbed areas, disturbance will be minimized to limit the risk <br />of introducing non-native species, and new populations of noxious or invasive plant species will be aggressively <br />targeted. <br /> <br />For sensitive alpine vegetation, surface disturbance will be avoided as much as possible, snow feoces will be <br />constructed to retain snow cover on high ridges or, alternatively, skiing and trail grooming during shallow snow <br />periods (< 8 inches in depth or as detennined during monitoring) will be prohibited. In addition, clearly marked <br />trails will be established for sununer visitors, and interpretative signs infonning hikers of the sensitive nature of <br />alpine tundra vegetation will be erected. <br /> <br />Section J/I <br />Vegelalion <br /> <br />19 <br />