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IX. Potential Pest Impacts <br />Various insects and diseases can infest urban forests, potentially killing trees and reducing the health, replacement <br />value and sustainability of the urban forest. As pests tend to have differing tree hosts, the potential damage or risk of <br />each pest will differ among cities. Fifty-three pests were analyzed for their potential impact and compared with pest <br />range maps (Forest Health Technology Enterprise Team 2014) for the conterminous United States to determine their <br />proximity to Alameda County. Six of the fifty-three pests analyzed are located within the county. For a complete <br />analysis of all pests, see Appendix VII. <br />5500 <br />5000 <br />4500 <br />4000 <br />3500 <br />0 3000 <br />2500 <br />� <br />2000 <br />z 1500 <br />1000 <br />500 <br />0 <br />m 0O O d coCL coCL <br />`O ~ z 3: <br />LLL <br />} <br />Pest <br />30 <br />25 0 <br />20 � <br />15 <br />10 <br />a <br />5 W <br />Cr <br />0 <br />Figure 12. Number of trees at risk (points) and associated compensatory value (bars) for most threatening <br />pests located in the county, City of Pleasanton <br />Mountain pine beetle (MPB) (Gibson et al 2009) is a bark beetle that primarily attacks pine species in the western <br />United States. MPB has the potential to affect 0.0 percent of the population ($2.31 thousand in replacement value). <br />Sudden oak death (SOD) (Kliejunas 2005) is a disease that is caused by a fungus. Potential loss of trees from SOD is <br />21.8 percent ($27.8 million in replacement value). <br />Thousand canker disease (TCD) (Cranshaw and Tisserat 2009; Seybold et al 2010) is an insect -disease complex that <br />kills several species of walnuts, including black walnut. Potential loss of trees from TCD is 1.5 percent ($2.19 million in <br />replacement value). <br />Western Bark Beetle (WBB) poses a threat to 0.0 percent of the City of Pleasanton urban forest, which represents a <br />potential loss of $0 in replacement value. <br />Western Five -Needle Pine Mortality (WFNPM) poses a threat to 0.0 percent of the City of Pleasanton urban forest, <br />which represents a potential loss of $0 in replacement value. <br />Page 17 <br />79 of 219 <br />