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The cottonwoods are generally concentrated on a slightly elevated and fairly dry shelf. But the willows are down in the thick rush and grass growth. As seen in the large wetland next to Exclosure 2, woody plants are very rare in the dense vegetative growth and those few are found on slightly elevated microsites. The vegetation of the lower elevation areas of Exclosure 2 is similar to the large wetland, although here there is a lot more grass and a bit less rush. In general the growth rate of the cottonwoods is good, but not great, except for a few individuals. The best growth, as has been seen elsewhere, is on locations that are slightly elevated. Growth in the wetter portions is less robust, but still making some gains. For cottonwood as well as willow, the dense carpet of grass and rush introduces intense competition for space and resources. The wetness of the soil is also limiting to cottonwood, but the fact that willow even has some difficulty might indicate that competition for space and rooting habitat is the most limiting factor. As the photographs show, the main advances in cottonwood growth occurred along the small embankments that identify former stream channel margins. Trees elsewhere are doing fine, but are not showing the same kind of growth advances. Cover: Overall cover in the exclosure is about 12.4% with 11.6% in cottonwood and 0.8% in willow. Cover in the woody vegetated areas where the cottonwoods are larger (mainly along the old streambank) is about 75% to 80%, but because there are large areas in the exclosure devoid of trees and inhabited by very dense herbaceous growth the overall woody plant cover is much reduced. Change in Height: Changes in the mean height of the plants, as has been seen elsewhere, was much greater between 2006 and 2007 than between 2007 and 2008. In part that rapid initial growth was a response to the removal of browsing. Once that response ended, then the trees put more energy into producing more leaves and short branches rather than gains in height. Furthermore, as many of the cottonwoods do not influence each other very much there is not much incentive to gain height when producing more leaves is more important. This pattern also appears to be true of the willows, although that is a bit harder to interpret as no willows were found in the 2007 sampling. No doubt the general dryness of the 2008 growing season had an effect on growth as well, but that may not have been much of a factor in this exclosure. One would expect that if water resources were limiting there would be some evidence of that in the thinning of the herbaceous growth. If anything, here the herbaceous growth became even thicker in 2008. So there might be some kind of complex competition occurring between the herbaceous and the woody growth that is limiting woody plant growth to some extent in moist to wet areas. Overall Conclusions: Exclosure 4 exhibits some of the same characteristics as Exclosure 2 and Exclosure 1 in a more advanced stage of development. That is, Exclosure 4 may be an indicator 2008 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 15