ARCHIVED REPORTS_YEAR SIX (2013) PHYTOREMEDIATION TREE MONITORING REPORT

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SECTION 4:TREE MONITORING RESULTS trees.The main stem of these uprooted trees was snapped, and the lateral surviving r branches will form a brushy growth habit. The three box elders that are counted as dead in Year 4 (2010) occur beneath a dense cottonwood canopy and it is possible that they are completely shade-suppressed but possess a live root-stock. If an opening in the tree canopy occurs in future years,it is possible that new lateral growth or stump-sprouts could form on these box elders. The average heath and vigor score for Area A is 2.5,which corresponds to a rank in between "high" and"medium' (Appendix A).This is the highest score recorded in any of the planting areas in Year 4 (2010). The health and vigor scores for this planting area have exhibited very little variation during Years 1 through 4,based on the similarity of scores recorded (Table 4-2). Year 5 (2011) As shown in Table 4-1,the Year 5 (2011) survivorship rate in Area A is 88 percent. This rate of survivorship is slightly lower than that observed in Year 4 (2010) (93 percent).Three box elders, one black willow,and one valley oak were counted as dead in Year 5 (2011) (Appendix A).The three box elders that are counted as dead occur beneath a dense cottonwood canopy and it is possible that they are completely shade-suppressed but possess a live root-stock.If an opening in the tree canopy occurs in future years, it is possible that new lateral growth or stump-sprouts could form on these box elders. In addition to the box elders,one black willow was recorded as dead. A small fire adjacent to Whiskey Slough Road during summer 2011 singed the foliage of a few trees in Area A in Year 5 (2011). One valley oak located a few feet away from the road was burned and recorded as dead in Year 5 (2011). The fire also burned the lower branches of a few other trees close to the road,and it is possible that these trees could die over the next few years,slightly increasing the average tree mortality in this planting area. The average heath and vigor score for Area A in Year 5 (2011) is 2.1,which is just slightly higher than a"medium' rank (Appendix A).This score is lower than the scores observed in previous monitoring years (Table 4-2).The drop in vigor score in Year 5 (2011) is due to the loss of tree foliage and branches that were burned in one small part of the planting sub area. Only a few trees were affected by the fire,and most of the vegetation will likely re-grow next season. However,it is possible that the burned trees could later succumb to insects or pathogens,and these trees will be re-examined during future site visits and system checks. Year 6 (2012) As shown in Table 4-1, the Year 6 (2012) survivorship rate in Area A is 90 percent. This rate of survivorship is slightly higher than that observed in Year 5 (2011) (88 percent). Survivorship rates in this planting sub area have been relatively consistent across all six monitoring years. Over the six-years of monitoring,the percent survivorship in this planting sub area has ranged from 86 to 93 percent(a variance of only 7 percent). Two box elders,one black willow,and one valley oak were counted as dead in Year 6 (2012) (Appendix A).The slight increase in survivorship in Year 6 (2012) compared with Year 5 (2011) is because one box elder that was recorded as dead in Year 5 (2011) had new growth this year.The two shade-suppressed box elders and one black willow were counted as dead a-a