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EXCLOSURE 1 - <br />General Description for 2011: This exclosure is located on the west side of the last area <br />to be mined north of the road crossing. The exclosure is long and narrow, paralleling the currently <br />indefinite stream channel through this area. The exclosure can be divided into three rather vague <br />zones. The most northerly third is the wettest and has dense growths of baltic rush (Juncus balticus) <br />as well as other wetland species. Woody growth here is mostly willow with some cottonwood, <br />mainly around the edges in drier soils. This grades to the south end which is dominated by <br />cottonwood in drier more elevated soils. The two graphs for this exclosure are shown on the <br />following pages. The graphs are followed by the photographs for this exclosure. <br />Good gains in growth of both woody and herbaceous vegetation continue. The first graph <br />shows data from a combination of all transects combined for the entire duration of the study. The <br />current year (far right of the graph) shows a large increase in average tallest plant height, but average <br />height and smallest plant height remain on essentially a straight line extension dating back to 2008. <br />The tallest plant height increase should not be interpreted to mean the tallest plant on the transects <br />increased that much, but rather that elsewhere in the exclosure there are plants taller than the <br />previously tallest plant on the transects. To judge increases overall, the average height line is most <br />representative. All things considered, the graph shows that the transects for exclosure 1 were highly <br />representative of the entire exclosure which leads one to a conclusion that the trends seen on the <br />transects are reasonably true elsewhere. <br />The second graph shows the percent change from the previous year for all data combined. <br />Once again, the trends and comparison of the current year data with transect data taken in prior years <br />remains consistent. This adds to a interpretation that the transect data taken in prior years is <br />reasonably representative of the exclosure as a whole. <br />The last two graphs specifically apply to only the current year data. These are frequency <br />distributions of the height data. The first graph shows data for cottonwood. The mean height lies <br />almost exactly between the two tallest bars and the number of plants that are taller and shorter than <br />the mean height are quite close to being equal. Looking closer, it is apparent that the curve is slightly <br />skewed toward the greater heights than the lower heights. This tends to support the conclusion made <br />previously that this exclosure is either density limited or becoming density limited. There is a <br />tendency to have more plants that are taller than the mean than shorter than the mean. This is <br />interpreted to indicate that new arrivals of cottonwood are somewhat less common now and the <br />plants that arrived earlier are beginning to dominate the cottonwood population. However, the skew <br />in the curve is not prominent and therefore this bias toward older, larger plants is still not very <br />strong. There is still a good deal of dynamic age distribution in the population. <br />The final graph is just like the similar graph for cottonwood, but this is for willow. The <br />interesting feature here is that the height curve shows a double peak. There is a lower peak for Salix <br />2011 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 6 <br />