National Geographic : 2015 Apr
Pine Beetles 101 ALBERTA, CANADA Since 2004 foresters in Alberta have cut more than a million infested trees, hoping to slow the beetle’s eastward march. Most felled trees are burned, like these near Grande Prairie. MONTANA On a ranch near Seeley Lake (left), a worker sprays a ponderosa pine with insecticide to fend off beetles. But spraying whole forests every year would be too costly and polluting.