There are over 5,000 ash trees along city streets. But the city's Department of Forestry wants City Council to approve removing 300 of them to thwart the advance of the menacing emerald ash borer. | The beetle, which is native to Japan, has already infested ash trees in more than a dozen states and Canada. It was first discovered in the US in 2002, when it destroyed over 400 million trees in Michigan alone. It was found last year in New York State in Cattaraugus County. "It's not a matter of if it will get here," says Brian Liberti, city forester. "It's a matter of when." | Removing the most distressed ash trees is a pro-active approach that might help to minimize the beetle's damage. The emerald ash borer's larva causes the most damage, feeding on the inner layers of the tree and weakening it until it dies. | The beetle is frequently transported as a stowaway in firewood. | Ash trees, which are known for their brilliant fall color, are in every Rochester neighborhood. | The removal, which is on Council's July 20 agenda, will cost about $150,000. Forestry technicians will replace the trees with a hardier variety.