Bark Beetles Kill Millions of Acres of Trees in West

On the side of a mountain on the outskirts of Montana’s capital city, loggers are racing against a beetle grub the size of a grain of rice. From New Mexico to British Columbia, the region’s signature pine forests are succumbing to a huge infestation of mountain pine beetles that are turning a blanket of green forest into a blanket of rust red. Montana has lost a million acres of trees to the beetles, and in northern Colorado and southern Wyoming the situation is worse. The black, hard-shelled beetle, the size of a fingertip, drills through pine bark and digs a gallery in the wood where it lays its eggs. When the larvae hatch under the bark, they eat the sweet, rich cambium layer that provides nutrients to the tree. They also inject a fungus to stop the tree from moving sap, which could drown the larvae. That fungus stains the wood blue. “The Latin name is Dendroctunus, which means tree killer,” said Gregg DeNitto, a Forest Service entomologist in Missoula, Mont. “They are very effective.” Source: New York Times