Bark beetle outbreaks refer to the events in which a large number of trees are killed by a dramatic increase in bark beetle populations. Unprecedented bark beetle outbreaks have been taking place across North America since 1990.  Between 1997 and 2010 more than 5 million hectares were affected by bark beetles in the western US [2]. 

Bark beetles are a natural part of forest ecosystems. They spend most of their lives under the bark of trees, feeding on wood and leaving behind tunnels. About 6,000 species of bark beetles are found in North America. Only a few bark beetle species, including the Mountain Pine Beetle and Spruce Beetle, are tree-killers. These beetles are not invasive species but native to North America. Currently, they have massive populations and are causing the death of entire forests. 

Bark beetles are tiny insects, about the size of a grain of rice. How does a tiny beetle kill such a large tree?  What is the cause of this massive population explosion? Watch the video to obtain relevant information.