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• <br /> 4.0 SAMPLE SURVEY RESULTS <br /> Street tree and planting site information was collected <br /> by VPB personnel on a ten percent statistical sample comprised <br /> of 170 points 0.8 kilometers long. All ten tree maintenance <br /> areas were represented in the sample. The results of the ten <br /> percent sample survey are summarized in Table 1 and Figures <br /> 1 and 2. <br /> Table 1. Street Tree Survey Results <br /> • A total of 8,045 trees and 3,668 planting sites were surveyed. This indicates <br /> an a of 60 trees and 27 planting sites per kilometer. <br /> • <br /> • Sample survey data projects approximately 76,828 trees (4/- 11,400) and 34,935 <br /> (•/- 6,080) planting sites at a 90 percent confidence interval. The high end <br /> of the confidence range, 65,O0O.trees, was used to calculate service Levels <br /> and tree care budgets. - <br /> • . The average Vancouver tree is 10.6 inches in diameter (Figure 1) and has an <br /> estiaiated.Yatue of 6911 using.,the International Society of Arboriculture's <br /> • . _ tree valuation facade. The tots( vsUi of all trees was. estimated at 570 <br /> . wiltion. : e i : ' ....: it . S.. - <br /> • Kuansan cherry: was the-most: comma? .species representing 13.4 percent' of <br /> population. This was,.followcd.by .T undereloud plum at 11.3 percent. Prunus <br /> us <br /> genera (flowering chenies collectively constitute 36 percent of <br /> the street tree population (Figure 2). . - <br /> �,, . <br /> • . Sore than two.thirds.(69- percent) : of the •triee - population was .less than 12 <br /> • <br /> me <br /> • inches in diater. ippcoxiaately 15 percent were medium size trees 12 to <br /> 18 inches in diameter and the remaining 16 percent were larger tha n 18 inches. <br /> . . .. . <br /> • Approximately 74 percent of trees were:less than 30 feet in height; 25 percent <br /> were between 30 and 60 .feet and only 1 percent were taller than 60 feet. <br /> • Based on the sample survey, approximately 945 trees or 1.2 percent need <br /> removet and percent of those were smaller than 6 inches 08K. Another <br /> 2,125 trees (3 percent) were classed as requiring safety trims because they <br /> had dead or hanging branches two inches in diameter or over. Of these <br /> approximately 25 percent had branches larger than 4 inches and were immediate <br /> priority. <br /> • <br /> • Overall the condition of Vancouver's street trees is good with 63 percent of <br /> samples rated in good or better condition. Japanese flowering cherry (other <br /> than Kwenzan) had the lowest percentage (43.8 percent) of trees in good or <br /> better condition of all species surveyed. <br /> The appraised value of the- street tree population based <br /> on the International Society of Arboriculture's tree valuation <br /> formula is $70,000,000 or an average of $911 per tree. <br /> -3- <br />