If the emerald ash borer makes it to South Dakota, Aberdeen could be in trouble, the city forester said. The emerald ash borer, which officials believe traveled to Michigan on ash packing materials from Asia, destroys ash populations when its larvae feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients. While there haven't been any reports of the ash borer in South Dakota, Aaron Kiesz, city forester, said it's just a matter of time. “Basically (the emerald ash borer) is throughout Michigan, Illinois on Ohio,” he said. “In those states they have firewood restrictions to help slow it from spreading.” South Dakota doesn't have firewood regulations, he said, but to help discourage bringing firewood from other states, parks and rec officials ask campers at Wylie Campgrounds to leave their firewood at home when they visit. “We have a huge percentage of ash (trees),” Kiesz said. “It would devastate us if the ash borer got here.” It's unknown just how many ash trees Aberdeen has, he said. That's why the forestry department will do a citywide tree inventory this summer. It's estimated that more than one-third of Aberdeen's street trees are green ash trees, he said. Tree diversification: “We're facing the unknown with our green ash,” he said. “We don't want people to panic, and it's not that we don't want to plant any more (ash trees), but we want to educate people and let them know of the importance of tree diversification.” Tree diversity wasn't popular with Aberdeen's early settlers, he said. The two most common trees in Aberdeen are elm and ash, he said. “South Dakota has highest percentage of green ash (trees) in the nation,” Kiesz said. “We have a lot to lose.” Recently, Aberdeen and other areas of the state have been struggling with Dutch elm disease, a fungal disease that kills American elm trees. The city has been battling the disease for six years. The first couple of years found about 800 infected trees. In 2003 and 2004, more than 1,000 trees were marked to be cut down. In 2005 and 2006, the number was back down to about 800, and this year the city marked 500 American elm trees to be cut down. Worse ahead?: While that number might seem high, Kiesz said the devastation caused by the emerald ash borer could be worse. “The difference is Dutch elm disease is picky and choosey,” he said. “The ash borer will go right down the line. It doesn't just want healthy trees.” There are many ways to help reduce the spread of the emerald ash borer, he said. Chemicals are being developed, but they're so expensive that it would be impossible for the city to use them to protect all the boulevard trees, he said. Another way to help control the bug is to release wasps, he said. Until the ash borer arrives in South Dakota, whether it's this year or in 50 years, city crews will continue to promote tree diversity, Kiesz said. That's really the only way to be proactive, he said.