2010-12-29_REPORT - M1988044 - Laserfiche WebLink

Home Browse Search

good moisture conditions and could send suckers up through the dry overlying material to produce a new clone tree where a seedling would never survive. Overall Conclusions: Exclosures 3, 4, and 5 appear to be maintaining a high degree of stability and consistency in the vegetation growth. As all three of these exclosures contain a more mature, but dense growth of trees and some shrubs, the current condition is probably in that in- between time that links the initial establishment and the competitive thinning stages in the forest development. The trees here are large, basically of the same age, and more or less the same size. In places they are quite dense. Although it would be difficult to determine, it is likely the woody vegetation biomass in these areas is probably approaching a maximum for the available resources. That is, total woody vegetation biomass will likely not increase a great deal for many years, if ever. However, the distribution of that biomass will shift from many smaller plants to fewer and larger plants while maintaining high utilization rates of the growth resources. This process that takes many years to complete has probably begun but is still in such an early stage that indications are extremely subtle and, without careful monitoring of individual plant groups for several years, clear identification of the process would be next to impossible. Otherwise, impressions of change is about all that can be relied on to observe the shift in biomass. CONCLUSIONS OF EXCLOSURE STUDIES FOR 2010 - All five exclosures have now reached a condition of reasonable developmental stability, with Exclosure 1 still showing the least. But even there both the woody and herbaceous growth is showing clear signs of maturation and reaching a plateau in the development. As was determined last year, Exclosures 3, 4, and 5 have reached the growth goals stated in the amendment. Some individual plants in Exclosures 1 and 2 have also reached that goal, but the rest of the cottonwoods are still a bit short of the goal. Willow growth in these two exclosures though has clearly reached a point of stability and there is high confidence they are established well enough to be considered capable of long term survival and persistence. Perhaps in 2010 the two younger exclosures will fully achieve the goals. As discussed in prior annual reports, there is clearly a wide range of conditions included in the exclosures that are supporting the redevelopment of the riparian corridor vegetation. These variations result in a cottonwood density range from very high to low, but all showing similar growth patterns. At the low density end is Exclosure 2 with widely spaced trees that generally grow without influencing each other. In this exclosure, plant sizes are amazingly uniform with only a few trees diverging from the norm. In contrast, Exclosure 1 is quite wet and here there is a stiff competition between the willows and cottonwoods but sufficient resources that both are showing signs of 2010 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 17