ARCHIVED REPORTS_YEAR SIX (2013) PHYTOREMEDIATION TREE MONITORING REPORT

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SECTION 4:TREE MONITORING RESULTS in tree survival is due to newg rowth recorded on trees previously assumed dead. In Year 4 (2010),one of the wind-damaged cottonwoods in this planting area that was recorded as dead in Year 3 (2009)formed new lateral branches next to the broken stem. Stump-sprouts (new growth arising from the ground) were noted in Year 4 (2010)next to the cottonwood that had been topped by beavers in Year 3 (2009). In Year 4 (2010),the average heath and vigor score was 2.3 (Appendix A). A score of 2.3 is ' slightly lower than in between"medium' and"high" ranks.Scores have varied little over the last four monitoring years. The Year 4 (2010)health and vigor score of 2.3 is slightly lower than the 2009 (2.5) and 2008 (2.4) scores,but is higher than the 2007 score of 2.2 (Table 4-2). Year 5 (2011) As shown in Appendix A,no trees were recorded as dead in this planting sub area in Year 5 (2011). The tree survivorship rate is 100 percent(Table 4-2).High tree survivorship (above 97%) was also noted in all previous monitoring years (Table 4-1). This planting sub area has the highest average survivorship rate of any of the six planting sub areas (Table 4-1). A small fire adjacent to Whiskey Slough Road during summer 2011 singed the foliage of a few trees in this planting sub area in Year 5 (2011).One trees was recorded as dead as a direct result of the fire,and the fire burned the lower branches of the trees located closest to the road. It is possible that these trees could die over the next few years, slightly increasing the overall tree mortality in this planting sub area. In Year 5 (2011),the average heath and vigor score was 2.0(Appendix A). A score of 2.0 corresponds to a medium rank. This vigor score is slightly lower than scores calculated in previous monitoring years (Table 4-2). The health and vigor score dropped slightly in Year 5 (2011) because one tree was recorded as dead and the lower branches of a few trees located next to the road were burned in the fire. Most of the vegetation is likely to re-grow next year.However,it is possible that the burned trees could later succumb to insects or pathogens,and these trees will be re-examined during future system checks or site visits. Year 6 (2012) The survivorship rate in this planting sub area in Year 6 (2012) is 98 percent(Table 4-1), slightly lower than that observed in Year 5 (100 percent) (Table 4-1).One cottonwood tree with a shade-suppressed growth form was recorded as dead this year;however,it is possible that the rootstock is still alive. If the canopy opens up, this tree may produce new lateral growth or might stump-sprout in future years. Over the 6-year monitoring period, the Addition to Area A planting sub area has had a very high survivorship rate (97 percent or higher) and survivorship varied only 3 percent across all 6 monitoring years (Table 4-1). In Year 6 (2012),the average heath and vigor score was 2.2(Appendix A),slightly higher than a"medium' rank. This vigor score is consistent with vigor scores calculated in all previous monitoring years except for a slight dip in the vigor ranks for this planting sub area in Year 5 (2011) (Table 4-2).The health and vigor score dropped slightly in Year 5 (2011) because foliage in one small part of the planting sub area was burned in the 2011 fire.The increase in the Year 6 (2012) vigor score compared with Year 5 (2011) is due primarily to the regrowth of burned tree foliage. 4-6