ARCHIVED REPORTS_2010 YEAR 4 PHYTOREMEDIATION TREE MONITORING REPORT

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SECTION 4:YEAR 4 TREE MONITORING RESULTS I ` Year 1 (2007) Three Fremont cottonwood trees (or 20 percent) died in this planting area during Year 1 `. (2007). The average health and vigor score in 2007 was 1.6,which fell in between the"low' and"medium' ranks.This was the second lowest health and vigor score of all the planting areas during Year 1 (2007) monitoring. Year 2 (2008) Survivorship in Year 2 (2008) (80 percent)was the same as Year 1 (2007). This planting area contained the same three Fremont cottonwoods that died during 2007.These trees were replanted in late November,2008,subsequent to the Year 2(2008) annual tree monitoring. Survivorship of these replanted trees will be assessed in Year 3 (2009). V The average health and vigor score for 2008 was 1.3,slightly lower than the average calculated for 2007(1.6). Health and vigor scores of both species contributed to the decline. L, This health and vigor score was the lowest of all six sub areas. Year 3 (2009) i 6 The rate of survivorship in Planting Area C in Year 3 (2009) increased to 93 percent from 80 percent as recorded in.both monitoring Years 1 and 2 (Table 4-1). One Fremont cottonwood died in Year 3 (2009) (Appendix A) compared to three trees in Years 1 and 2 V. (2007 and 2008). The heath and vigor scores for trees within this planting area in Years 1,2,and 3 are below a irank of 2(or in between"low' and"medium" health and vigor ranks) (Table 4-2). The health and vigor scores calculated in Year 3 (2009) increased slightly compared to the scores in Year 1 (1.6) and Year 2 (1.3).The Year 3 (2009) score of 1.9 is only slightly between a "medium' rank (Table 4-2). The trees within this planting area are short for their age and it is likely that the roots are still confined to the engineered fill zone. Tree growth and health and vigor scores are expected to increase once tree roots extend beyond this compacted Llayer. Year 4 (2010) L, The rate of survivorship in Planting Area C in Year 4 (2010) is 93 percent(Table 4-1),the same value as reported in Year 3 (2009). The Fremont cottonwood that was recorded as dead in Year 3 (2009) did not resprout,as some cottonwoods did onsite,but no additional trees Ldied in Year 4 (2010). Lower survivorship rates (80 percent) were recorded for both Years 1 and 2 (2007 and 2008) (Table 4-1). In Year 4 (2010),the health and vigor score for this planting area (2.2) increased above a rank of 2 or"medium' for the first time (Appendix A). Previously, the heath and vigor scores for trees within this planting area in Years 1,2, and 3 were below a rank of 2 (or in between "low" and"medium' health and vigor ranks) (Table 4-2). The health and vigor scores calculated in Year 3 (2009) increased slightly compared to the scores in Year 1 (1.6) and Year 2 (1.3).The Year 3 (2009) score of 1.9 is slightly below a"medium' rank (Table 4-2). L Despite the small increase in the health and vigor score in 2010,the trees within this planting area remain short for their age and it is likely that the roots are still confined to the SAG1667491103500001(YEAR42010_HOLTTREE MONITORING_REPORT-FINAL.DOC%) 47