For an ash tree, this process can be fatal. Trees transport nutrients and water through their bark, and by gouging holes through that bark, the ash borers sever the tree’s roots from its branches. “It essentially cuts off the circulation of the tree,” Hudgins says. The ash borer was first spotted in North America in 2002.
https://www.sierraclub.org/sierra/ash-trees-are-dying-everywhere-why

