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the first year after the removal of browsing which increased density up to near the holding capacity. <br />Woody plant growth however showed strong gains, in spite of the dry 2008 growing season. It <br />appears that these plants were tapping into the groundwater to a much higher degree. <br />Overall, woody species density here is obviously far less than in Exclosure 1. Here the woody <br />plants are widely distributed over the site, except for the very dry, sandy locations where only <br />scattered grasses are found. <br />Results of Sampling: The four graphs for this exclosure show the same analysis as for <br />Exclosure 1. However, the results differ in significant ways. <br />The first graph shows that the transects previously taken were not highly representative of the <br />exclosure as a whole. There is a strong change in the direction of the lines in the current year. <br />Average height for the exclosure as a whole is somewhat less than was found in the transects. Later it <br />will become evident why that is the case. The second graph also shows this same dramatic change in <br />the lines. From this it can be interpreted that there is a larger abundance of smaller plants than larger <br />plants in the exclosure as a whole than was found on the transects. In fact, that is actually not the <br />case. <br />The third graph shows the frequency distribution of heights for cottonwoods. The shape and <br />distribution of the data frequency is quite similar to the same graph for cottonwoods in Exclosure 1. <br />However, there is a very slight skewing of cottonwood height toward the lower end or smaller sizes. <br />There are much fewer big cottonwoods and the ones that are there are quite large, reaching up to 15 <br />feet. However, the mean height in Exclosure 2 is about 1.5 feet taller than the mean height in <br />Exclosure 1. <br />Looking at the fourth graph, the height distribution for the willows, shows a similar mean <br />height but most all of the willows are bunched down toward the smaller sizes. The tall willows <br />though are quite tall even though few. <br />As has been discussed before, this exclosure generally exhibits an open, non - contagious <br />distribution that results in reduced competition and steadier gains. If fact, from the standpoint of <br />height, Exclosure 2 is more successful than Exclosure 1. But density is considerably less. Thus, it <br />appears that for the exclosure as a whole, larger plants are produced with a lower density in the same <br />amount of time and that usually indicates that dense growth, although more desirable in some <br />respects, limits height due to competition for resources. <br />This exclosure is drier than Exclosure 1 and the impact of dry seasons is greater, but wet <br />seasons tend to induce a robust growth rate. Of course, without knowing exactly what the sub- <br />surface moisture structure is it is hard to determine whether the moisture factor is linked closely to <br />the stream corridor groundwater or is more linked to precipitation. One indicator that there is a link <br />to groundwater is the fact that the growth curves do not show pronounced humps and valleys that <br />would be associated with decreased moisture in dry years and increased moisture in wet years. <br />2011 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 10 <br />