OMAHA, Neb. (AP) — Omaha Mayor Jean Stothert says Nebraska's largest city is prepared for an invasion of a tiny menace that has killed thousands of ash trees in 21 other states since the early 2000s. The Omaha World-Herald reports (http://bit.ly/1IfHLtT ) that Stothert balked Friday at plans to hire more tree trimmers and buy tree removal equipment in anticipation of an emerald ash borer infestation.