Recent bark beetle outbreaks have resulted in the loss of hundreds of thousands of conifers on approximately 74 million acres (30 million hectares) of forest in western North America during the last decade. Stand conditions, drought, and warming temperatures have contributed to the severity of these outbreaks, particularly in high-elevation forests (USDA 2009). Many forests remain susceptible to bark beetle infestation and will continue to experience high levels of conifer mortality until suitable host trees are depleted or natural factors cause beetle populations to collapse.