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area covered by a particular constituent rather than cover classes or close-fitting polygons, to obtain an <br />estimate of absolute or foliar cover. The estimated mean cover for a particular constituent in the type <br />was derived by summing the cover estimates in each plot and dividing by the total number of plots <br />sampled. <br />The remainder of the Swale/drainage type consists of a scrub/shrub component dominated by virtually <br />inpenetrable thickets of willow. The thickets comprise approximately 20 percent of the Swale/drainage <br />type, existing as islands or stringers of vegetation within the graminoid component. The majority of the <br />islands and stringers of willow range in size from approximately 0.1 to 0.25 acres. One stand, located in <br />Swale/drainage vegetation on the west side of the proposed permit area is larger (approximately 2.5 <br />acres In size). Only qualitative estimates of herbaceous and shrub cover were made in this component <br />due to its inherent immeasurability and the lack of pertinent information that would be achieved from <br />quantitative sampling attempts. <br />Peabody originally intended to use the point-intercept technique to measure cover in the Swale/drainage <br />type. However, after utilizing the method in the field it became apparent that the technique was <br />inappropriate for use in the Swale/drainage vegetation. The reasons for this are related to the type of <br />vegetation, the morphology of the plants, and the structural complexity of the herbaceous foliage. <br />• Primarily, the predominance of a rather tall and densely intermingled stand of graminoids with long <br />narrow stems, and a very heavy litter component in the foliage contributed to the problem. The end <br />result was that the observors were unable to accurately determine the identity of the vegetation being <br />contacted, or In cases where vegetation was encountered deep within the canopy, whether a hit was <br />indeed registered. Shadowing within the canopy very nearly precluded any accurate observations even <br />during mid-day. When a hit could be registered, it usually required a thorough investigation through the <br />foliage to ascertain the species intercepted. The sorting through the canopy tended to disturb the <br />surrounding vegetation, thereby biasing adjacent point projections. With these problems noted, alternate <br />sampling methodology was selected (ocular estimates) which proved more satisfactory. Concurrence <br />with the change was obtained from the OMLR via letter correspondence dated September 3, 1987 from <br />Mr. Peter O'Connor to J. Lunan of Peabody. <br />Plant species frequency or presence was derived by dividing the number of plots or transects at which a <br />species occurred by the total number of plots or transects sampled in each of the three vegetation types <br />for which cover samples were obtained. Products were multiplied by 100 to express frequency as a <br />percentage. <br />(REVISED 8775100) 2.04.10 - 15 <br />