Arboriculture & Urban Forestry 41(3): May 2015 peak emergence of EAB, researchers used their assessment scheme to rate ash trees, and selected ap- proximately equal numbers of Good, Fair, and Poor trees at each site. One hundred fiſty-nine trees were rated in Lafayette and were comprised of 71 Good, 52 Fair, and 36 Poor trees at four locations (Table 2). In Indianapolis, 151 trees comprised of 45 Good, 58 Fair, and 48 Poor trees at four locations (Table 2). Trees were rated using the researchers’ assessment scheme, and their growth measured each year in June for four years through 2013 (Table 2) to track the health of the urban forest at each site. DBH of each tree was measured to determine the extent to which size influenced EAB attack (Marshall et al. 2009; McCullough et al. 2009a; McCullough et al. 2009b). Trees were between 14 and 40 cm DBH, which rep- resents the median class of street trees at the two study sites (Peper et al. 2008; Shaw pers. comm.). The abundance of common wood borers was quantified in each of the 310 trees. The number of insect emergence holes on the basal two meters of each tree were counted to monitor insect attack over the course of the study. A similar method has been used to rapidly estimate the density of the ceramby- cid Enaphalodes rufulus, the red oak borer (Fierke et al. 2005). Each year, researchers marked holes with a different color of enamel paint (The Testor Table 1. EAB-specific assessment scheme. Category Good Biotic factors Crown condition Structural problems No significant damage Full, balanced, <10% thinning None Fair Damage is evident but from a non-fatal causal agent Imbalance is evident, 10%–30% thinning Minor, or if tree appears to have been topped 127 Corporation, Rockford, Illinois, U.S.) to track the annual emergence of borers from 2010 to 2013. Specifically, researchers monitored for emergence holes created by the redheaded ash borer (Neoclytus acuminatus), eastern ash bark beetles (Coleoptera: Curculionidae, Hylesinus spp.), clearwing moths (Lepidoptera: Sessidae, Podesia spp.), carpenter worms (Lepidoptera: Cossidae, Prionoxystus spp.), and EAB. Each borer creates an emergence hole of diagnostic shape and size, which allowed the quantifying of emergence holes by insect taxon. Statistical Analysis All statistical analyses were conducted in Statis- tica Version 10 (StatSoſt Inc. 2011). To determine the rate of ash decline, the vigor class of all trees at each site and in each year was compared using Friedman ANOVA. Kaplan-Meier survival curves were calculated using June 2010 as the beginning of the study and June 2013 as the end (Kaplan and Meier 1958). Trees that declined to the Criti- cal vigor class were considered censored data in the analysis because they were physically removed for safety reasons. A log-rank test was performed to compare the rate of decline between the two sites. To determine the extent to which vigor class affects first detectable colonization of a tree by EAB, Vigor class Poor Damage is significant and by a potentially fatal agent Imbalance is significant, 30%–80% thinning Significant Critical Damage is probably fatal; tree is unsalvageable Crownless, >80% thinning Major Table 2. List of sites and locations of trees, and dates each year when evaluations were performed. Site Coordinates Lafayette, Indiana, U.S. Sagamore Parkway Greenbush Street Downtown Tippecanoe Mall Indianapolis, Indiana, U.S. Sahm Park Sahm Golf Course Holland Park Flowing Well Park 40°27’11.2”N, 86°54’39.3”W 40°25’48.8”N, 86°53’23.1”W 40°25’12.0”N, 86°53’36.2”W 40°23’31.0”N, 86°51’05.9”W June 24 39°55’01.7”N, 86°03’27.8”W 39°54’58.0”N, 86°03’12.8”W 39°57’56.5”N, 86°01’14.6”W 39°57’24.4”N, 86°05’01.8”W June 16 June 12 June 13 2010 June 23 2011 June 22 2012 June 13 2013 June 14 ©2015 International Society of Arboriculture
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