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land use subcomponent of rg azin lg and), herbaceous production of the revegetated area <br />will be considered adequate for final bond release if it is not less than 90% of the <br />herbaceous production, as determined from the reference areas with a 90% statistical <br />confidence utilizing a standard students statistical t-test comparison of the means. As <br />allowed under the rules promulgated on 9/14/05, these comparisons may utilize one of <br />three methods detailed under Rule 4.15.11 (2) [(a), (b) or (c)]. As allowed by Rule 4.15.7 <br />(4), either weighted-average or individual protocols will be followed. For grassland <br />testing the weighted average approach (Rule 4.15.7 (4) (b)) will be utilized where <br />reference area data and revegetated area data are "weighted" (each combined into single <br />values for comparison) based on the proportional acreage of pre-mine communities <br />within the disturbance area footprint. Testing will then follow procedures detailed under <br />Rule 4.15.11 (2) with preference being given first to subsection (a) [direct comparison], <br />second to subsection (c) [reverse-null testing], and third subsection (b) [classic t-test]. <br />For Post-2008 sagebrush steppe revegetation (targeting the rangeland land use <br />subcomponent of wildlife habitat), herbaceous production of the revegetated area will be <br />considered adequate for final bond release if it is not less than 70% of the herbaceous <br />production as determined from the reference areas with a 90% statistical confidence <br />utilizing a standard students statistical t-test comparison of the means. If necessary, a <br />reverse-null hypothesis testing procedure may be utilized in accordance with procedures <br />detailed in Rule 4.15.11 (2) (c). As inferred under Rule 4.15.8 (3) (ii), relaxation of the <br />herbaceous production standard for areas targeting wildlife habitat post-mining land uses <br />is designed to compensate for revegetation techniques (prescribed ecological reclamation <br />approach) that must discourage grasses to encourage shrubs in the post-revegetated <br />community. Justifications for reduction to 70% are identical to those presented for cover <br />in the previous section. <br />Woody Plant Density - Pre-2008 Reve etg_ation <br />Cedar Creek Associates, Inc.'s recent in-depth analysis of past "shrub conducive efforts" <br />(report dated April, 2007) attempted by Colowyo on older (pre-2008) reclamation has <br />resulted in the conclusion that such past efforts can largely be considered a failure and <br />techniques such as bare-root or containerized plantings should no longer be attempted. It <br />has become obvious to all parties concerned (including Colowyo, their consultants, the <br />researchers at Colorado State University, the CDRMS, and the CDOW) that reclamation <br />practices utilized historically were far more conducive to establishing herbaceous species <br />at the expense of woody species. (It is for this reason that post-2008 reclamation, using <br />different reclamation techniques will have a different success criterion.) <br />Furthermore, the continued existence of herbaceous species at elevated densities, along <br />with browsing by big game animals, continues to preclude opportunities for <br />establishment and/or growth of woody species populations. In effect, historic (and <br />expensive) attempts to establish shrub populations into these "dense herbaceous stands" <br />using the best technology available at the time have met with nearly complete failure. <br />Only a few remnant plants and "patches" of shrubs remain in the reclamation, and many <br />4.15-17 Revision Date: 3/14/08 <br />Revision No.: TR-72