CONCORD, N.H. — There are signs of a second infestation of a destructive beetle targeting ash trees in New Hampshire.

The Concord Monitor reports state forestry officials say the presence of the emerald ash borer in Merrimack County appears to be unrelated to one discovered in Concord last spring.

The beetle has been detected on the border between Canterbury and Loudon in an area about 3 miles long by 2 miles wide.

The emerald ash borer, a native of China, was first discovered in Michigan in 2002.

When the beetle was first was spotted in Concord last year, scientists pounced, working quickly to try to protect the state’s 25 million ash trees — about 6 percent of New Hampshire’s forests — including white, green and black ash varieties.