Tree pests

The document discusses the emerald ash borer, an invasive beetle species native to China that was introduced to the United States in the 1900s through infested wood packing material. It has since killed over 20 million ash trees across the Midwest by tunneling under their bark and laying eggs. While oaks and aspens are most commonly infested, it also threatens ponderosa and Coulter pine trees in western states. Efforts to prevent further spread include firewood quarantines.