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i <br /> SECTION 4:TREE MONITORING RESULTS <br /> The heath and vigor scores for trees within this plantingarea in Years 1 2 and d 3 are below a <br /> rank of 2 (or in between"low' and"medium' health and vigor ranks) (Table 4-2). The <br /> ' health and vigor scores calculated in Year 3 (2009) increased slightly compared to the scores <br /> in Year 1 (1.6) and Year 2 (1.3). The Year 3 (2009) score of 1.9 is only slightly between a <br /> "medium" rank(Table 4-2). The trees within this planting area are short for their age and it <br /> ' is likely that the roots are still confined to the engineered fill zone.Tree growth and health <br /> and vigor scores are expected to increase once tree roots extend beyond this compacted <br /> layer. <br /> ' Year 4 (2010) <br /> The rate of survivorship in Planting Area C in Year 4 (2010) is 93 percent(Table 4-1), the <br /> same value as reported in Year 3 (2009). The Fremont cottonwood that was recorded as dead <br /> in Year 3 (2009) did not resprout,as some cottonwoods did onsite,but no additional trees <br /> died in Year 4 (2010). Lower survivorship rates (80 percent) were recorded for both Years 1 <br /> and 2 (2007 and 2008) (Table 4-1). <br /> In Year 4 (2010), the health and vigor score for this planting area (2.2) increased above a rank <br /> of 2 or"medium" for the first time (Appendix A). Previously,the heath and vigor scores for <br /> trees within this planting area in Years 1,2,and 3 were below a rank of 2 (or in between <br /> "low" and "medium" health and vigor ranks) (Table 4-2). The health and vigor scores <br /> i calculated in Year 3 (2009) increased slightly compared to the scores in Year 1 (1.6) and <br /> Year 2 (1.3). The Year 3 (2009) score of 1.9 is slightly below a"medium" rank (Table 4-2). <br /> Despite the small increase in the health and vigor score in 2010,the trees within this <br /> planting area remain short for their age and it is likely that the roots are still confined to the <br /> engineered fill zone. Tree growth and health and vigor scores may increase once tree roots <br /> extend beyond this compacted layer. <br /> Year 5 (2011) <br /> The rate of survivorship in Area C in Year 5 (2011) is 87 percent(Table 4-1),slightly lower <br /> than the rate calculated in Year 4 (2010). Two Fremont cottonwood trees were recorded as <br /> dead in Year 5 (2011). These trees potentially could re-sprout from the root-stock and this <br /> will be checked during future system checks and site visits. <br /> In Year 5 (2011),the health and vigor score for Area C was 1.9 (Table 4-2).This is a slight <br /> decrease compared with the Year 4 (2010) score of 2.2 (Appendix A).A score of 1.9 is <br /> between"low" and "medium'. The heath and vigor scores for trees within this planting sub <br /> area in Years 1 (2007),2 (2008),and 3 (2009)were also below a rank of 2 (Table 4-2). <br /> The rate of tree growth in Area C is much slower than that observed in trees in Areas A, <br /> Addition to A,Area AA,and Area B. In Area C, the trees are short for their age, and it is <br /> likely that the roots are still confined to the engineered fill zone. Tree growth and health and <br /> vigor scores may increase once tree roots extend beyond this compacted layer and reach the <br /> native soil and groundwater. <br /> Year 6 (2012) <br /> The rate of survivorship in Area C in Year 6 (2012) is 87 percent(Table 4-1),the same rate as <br /> recorded in Year 5 (2011). Similar to Year 5 (2011),two Fremont cottonwood trees were <br /> ' 411 <br />