U.S. Bark Beetle Outbreaks

A look at how climate change is fueling the current outbreak of bark beetles in the southeast U.S. and southwest U.S.

A Windows to the Universe presentation to accompany the Bark Beetle Outbreaks

Classroom activity

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Changing Planet: Bark Beetle Outbreaks

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NBC Learn Video – Bark Beetle Outbreaks

Bark Beetle Summary

• They are native to North America.• They are about the size of a grain

of rice.• They are an important part of the

forest ecosystem.

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They work together to eliminate weakened trees, so new, more vigorous trees can grow in their place. There is a major outbreak of bark beetles in the southeastern U.S. (Southern pine beetle Dendroctonus frontalis) and the western U.S. and Canada (Mountain pine beetle Dendroctonus ponderosae).

Current Outbreak Fueled by Climate Change

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- Current outbreak has been linked to a warming shift in climate, which has produced long-term drought

- Drought makes trees weak and thus they are susceptible to bark beetle attack

- The double whammy of this scenario is that warming climate is causing shifts in where beetle populations can live; and it is allowing bark beetles to overwinter in higher numbers and reproduce more quickly.

Pine bark beetles have been charged with killing 47 million hectares of pine trees throughout U.S. Trees that have been killed because of pine bark beetles have brown needles in this picture.

Bark Beetle Lifecycle and Pheromone Research

• Female beetle lands on tree.• Female decides to make the tree her home by

boring into the tree.• Female secretes a pheromone to attract hundreds

of other bark beetles to the same tree. This means a mass attack and death for the tree.

• Adults reproduce and lay eggs. Eggs hatch into larvae under the bark of the tree. Larvae emerge from tree and fly to a new tree host.

• Major studies into the pheromones of bark beetles are ongoing, even at a genetic level. Scientists are working to understand this process in hopes of preventing devastating outbreaks in the future.

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Larvae of a mountain pine beetle & bore holes of the small southern pine engraver beetle

Actions for the Concerned• There are many different types of

bark beetles that affect many different kinds of trees.

• Many government and concerned groups are removing dead or diseased trees, leaving more room for thriving trees to live.

• Concerned citizens are watering trees with much needed water they need to stay healthy.

• Take care when camping or driving in areas where trees are infected by bark beetles. Dead trees will eventually tip over and the time and direction of their fall is unpredictable!

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