The mountain pine beetle is one step closer to crossing North America and turning eastern pine forests into the same bleak landscapes that have scarred the Mountain West in recent years.
Some scientists say it is inevitable that the tree-killing insect will spread all the way east via a corridor of jack pines across northern Canada's boreal forest. The question is: When? Others are more skeptical.
Either way, researchers have now shown that the beetle has invaded a new species of pine on the eastern side of the Rocky Mountains in Alberta, Canada, with potentially serious consequences.