ARCHIVED REPORTS_REPORTS - Laserfiche WebLink

Home Browse Search

• • • • SECTION 6.0 EVALUATION OF REMEDY PERFORMANCE • • Most trees with leaf necrosis are located in the northwestern portion of the site,in the area • where fly ash was reported previously. • The trees in the original test grove as of August 2011 are shown on Figure 6-1. • 6.1.3 Turnaround Area—Annual Review Since observations in August 2010,4 of the 60 remaining poplars in the turnaround area • have died. Many of the remaining poplars started exhibiting signs of severe infestation and • may die in the next few years.Since 2003,dead poplars in the turnaround area have been • replaced with sycamore,fruitless mulberry,and black locust. The tree species were intermixed during planting to increase localized species diversity.Approximately four • losses were observed between the 2010 and 2011 site visits for the sycamore,fruitless • mulberry,and black locust trees.The trees in the turnaround area as of August 2011 are shown on Figure 6-1. • • 6.1.4 North of Warehouse Planting Location —Annual Review • In the area north of the warehouse,trees nearest the warehouse continue to exhibit signs of leaf necrosis.The fruitless mulberry trees are exhibiting signs of leaf necrosis in addition to • the sycamore and Paulownia.Symptoms are similar to but more severe than those observed • on trees in the original test grove.The trees farther from the warehouse are performing • better than trees on the southern boundary of the grove,likely because they had less exposure to fly ash when the warehouse collapsed. Although leaf necrosis was observed in • this planting location,no Paulownia trees have been lost since August 2007. Approximately 55 sycamore trees and 12 mulberry trees are growing in the planting area.One sycamore • and one fruitless mulberry tree died between the 2010 and 2011 site visits,but no losses were observed between 2008 and 2010.The distribution of the Paulownia,sycamore,and • fruitless mulberry trees in the planting location north of the warehouse is shown on • Figure 6-2. Additional emitters or longer irrigation period in this area may improve tree performance at this planting location;this will be considered in 2012. • • 6.1.5 Former Bagging Plant—Annual Review • Approximately 16 poplar trees have died and 20 poplar trees have become severely infested since the 2010 site visit.Approximately 100 poplar trees have died since August 2008 and • tree mortality is expected to continue over the next few years. Approximately 40 trees were • replaced in the former bagging plant area between 2008 and 2010.The tree species were • intermixed (sycamore,black locust,and fruitless mulberry) to increase localized species diversity.Figure 6-3 shows the distribution of trees in this planting location. During the 2011 site visit,in general,the replacement fruitless mulberry trees were performing well. A few black locust trees showed symptoms of leaf chlorosis (yellowing), • which may have been caused by the presence of aphids.This was similar to what was • observed during the 2010 site visit,but the symptoms did not appear to be getting worse. • • • • • RDD1112370001(CAH5003.DOCx) 6-3 �riazroanoo • • •