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transect. In 2006 there were 6 cottonwoods and 3 willows. The middle and northerly transects have <br />most of the cottonwoods and all of the willows. <br />In comparing the 2006 results with the 2007 and 2008 results it is apparent that there has <br />been an increase in the number of woody plants, except for the southern transect which showed a <br />decline due to a drier habitat. The number of cottonwoods nearly doubled and the number of <br />willows increased four times. Mean cottonwood height increased from about 2 feet to about 4 feet <br />with the tallest plant increasing from about three feet to about nine feet. Willows, however, on the <br />average did not change much, but the largest willow showed a change not unlike the change in the <br />largest cottonwood. <br />It is interesting though that the minimum height of both cottonwood and willow did not <br />change very much over the three years. This disparity between large increases in at least the larger <br />plants of both species and little change in the smallest plants can only be explained by looking at the <br />increase in the numbers of plants as well as considering local adversity in the habitat. In effect, new <br />plants are still arriving in the overall community composition. In some cases, previously small plants <br />are still small simply because growth resources are too limited to allow much growth beyond <br />survival levels. <br />Cover: Cover in Exclosure 2 has increased by about two times since 2007. It wasn't <br />measured in 2006 as cover then was negligible. Overall, the cover is about 12%. But here there is a <br />smaller difference between willow and cottonwood with cottonwood showing about 5% cover and <br />willow about 7% cover. These values are still quite low, but considering the size of the exclosure, the <br />wide distribution of the plants, and their comparatively small stature such low values are expected. It <br />is more important, at this point, to look at changes in numbers of plants and changes in the <br />dimensions of the plants. So long as those two elements increase, cover will also increase. <br />Change in Height: When examining the change in height, an interesting and significant <br />pattern emerges. Although there are fewer trees on the south side, the trees that are there are growing <br />much more rapidly than those in the middle of the exclosure and especially those on the north side of <br />the exclosure. Willow, on the other hand, somewhat exhibits the opposite pattern. Willow is stronger <br />on the north than the middle or south. On the south, the only willows are near the large wetland. <br />Although the data presented here does not show this, willow is more common on the west <br />side of the exclosure than the east side. This was shown in the 2006 report where plants along the <br />transect are plotted. In 2009, this kind of a longitudinal plot will be returned to so a comparison can <br />be made between 2006 and 2009 to identify any patterns of zonation. <br />Overall Conclusions: It appears that a similar pattern to that seen in Exclosure 1 is evident <br />on the north side of Exclosure 2. That is, willows and cottonwoods are competing here. In fact, that <br />2008 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 9