 It's amazing how much a tiny little insect about the size of a grain of rice can change whole forest landscapes. Mountain pine beetle is native to the Rocky Mountains and can cause devastating effects when an outbreak occurs. Mountain pine beetle can be found from Canada to Mexico and sea level to 11,000 feet. At normal levels, these beetles help thin and rejuvenate forests by killing older or stressed trees. However, when there is a huge population explosion, epidemic levels are reached and entire forests are in danger. There was a drought in the Rocky Mountains in the late 1990s to early 2000s that stressed trees. The drought, in combination with warmer winters and old dense forests, triggered an epidemic. By 2012, beetles had killed nearly all of the mature lodgepole pine trees in southern Wyoming and northern Colorado, over 1.5 million acres. The total impact of the mountain pine beetle outbreak was 3.4 million acres. Mountain pine beetle flies slowly about the speed of human walks and they only fly a short distance to their next host. It takes numerous beetles to kill trees. These limitations make the feet of killing millions of acres of trees quite mind-blowing. From the University of Wyoming Extension, I'm Mae Smith, Exploring the Nature of Wyoming.