Did you know Canada.. the mountain Pine Beetle is invading Alberta!
Mountain pine beetles are about the size of a grain of rice. But easily kill trees by boring through the bark into the phloem layer on which they feed and in which eggs are laid. Pioneer female beetles initiate attacks, producing pheromones that attract more beetles. Within about two weeks of a beetle attack, the trees starve to death as the phloem layer is damaged enough to cut off the flow of water and nutrients. Older trees usually succumb first. After particularly hot summers, the mountain pine beetle population can increase dramatically, deforesting large areas.
Source: Science Daily, Wikipedia