50 Sydnor et al.: Economic Impact of Emerald Ash Borer categories. Size categories were determined as natural breaks by the arborist contacted. Total costs include removing both the tree and the stump. Arborists were told to assume that the tree was readily accessible and not encumbered by proximity to buildings or utilities. Actual prices for a given site might be two to three times higher as a result of encumbrances. Median prices are reported because this represents an actual bid and follows the precedent set by the national tree valuation guide- lines (Council of Tree and Landscape Appraisers 2000). Calculations of the landscape values of the trees were made using the trunk formula method procedures set forth in Guide for Plant Appraisal (Council of Tree and Landscape Apprais- ers 2000). Location and condition values were determined as suggested by the national guide in that the first author visited a number of communities to develop an average value for location (60%) and condition (70%). Park trees were, in gen- eral, farther from structures or human activity and more likely to be in groups thus location values for park trees were esti- mated at 50%. The national guide remands basic prices, spe- cies values, and the size of the largest transplantable tree to the states or regions. The state guide used was Guide to Appraisal of Trees and Other Plants in Ohio (Sydnor et al. 2002). Simplistically speaking, the landscape value of a tree is its basic value as determined by the state guide multiplied by the species, condition, and location percentages expressed as decimal fractions. RESULTS AND DISCUSSION Sample Description A total of 67 communities of the 200 contacted responded to the request for information for a response rate of 33%. Com- munities responding represented 2,815,945 citizens or 25% of Ohio’s 2000 census population of 11,353,140 individuals (United States Census Bureau 2005). The average household income of responding communities was $43,909 and the me- dian of responding communities was $38,000. These values are consistent with Ohio’s median income of $40,956 (United States Census Bureau 2005). Numbers of Ash Trees in Ohio Communities Fifty-four communities reported the size of ash street trees in their communities. The average size reported by the commu- nities was 34 cm (13.6 in) dbh. To adjust for variations in size as reported by different communities, normalized dbh was calculated as 31 cm (12.4 in) dbh. Normalized dbh will be used for future calculations. Sixty-three communities reported the number of street trees in their community as well as the percentage of all ash trees such that the number of ash street trees per 1000 resi- dents could be calculated. Considerable variation was seen with an average of 20.5 ash trees per 1000 residents, but a median of only 8.3 trees per 1000 residents (Table 2). This kind of spread between mean and median is believed to rep- ©2007 International Society of Arboriculture Table 2. Numbers of ash trees as street, park, and private trees per 1000 residents are given as reported by the responding communitiesz . Item Median/1000 residents Mean/1000 residents Number of responses Ohio tree totalsy (median-based) Ohio tree totalsx (mean-based) Street ash 8.71 20.50 63 98,885 232,739 Park ash 2.89 38.28 58 32,811 438,598 Private ash 76.92 320.92 47 873,284 3,643,450 zTotal numbers of ash street, park, and private trees in Ohio adjusted for Ohio’s total population are given. xMean-based totalsmean trees per 1000 residents/(Ohio population/1000 residents). yMedian-based totals median trees per 1000 residents/(Ohio population/ 1000 residents). resent different kinds of communities and is discussed later. When the mean and median numbers are adjusted to account for Ohio’s total population, the number of ash street trees is between 98,885 (median) and 232,739 (mean). Fewer communities (n 58) reported the number and percentage of ash trees in their parks. Tree boards represent- ing Tree Cities are often charged with responsibility for street trees but not park trees and have even less responsibility for private trees. The communities reporting identified an aver- age of 38.3 ash trees per 1000 residents and a median of 2.9 ash trees per 1000 residents (Table 2). The amount of park land varies greatly among Ohio’s communities as does the relative amounts of active and passive parks. Adjusting the mean and median to account for Ohio’s total population, the number of ash park trees is between 32,811 (median) and 438,598 (mean). Still fewer (n 47) communities gave a complete re- sponse as to the number of trees on private property and an estimate of the percent of ash on private property but within community boundaries. Several communities informed us that they were less comfortable in reporting on private trees as they did not keep records on private trees. As a result, a number of communities did not report all of the requested data for park or private trees. Estimates from the 47 commu- nities reporting had an average of 320.9 private ash trees per 1000 residents and a median of 76.9 ash trees per 1000 resi- dents. Several calls were made regarding this category. We found that reporting communities we contacted were com- fortable with their estimates and could normally explain their original estimates and why their estimates might vary from statewide averages. As expected, even more private trees were reported compared with street and park trees. When the mean and median numbers for private ash trees per 1000 are adjusted upward to account for Ohio’s total population, the
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