Triggered by drought, a shorter frost season, and conditions created as a result of fire surpression, mountain pine beetle populations grew across a landscape of mature, dense, homogenous lodgepole pine trees. The long-term drought weakened tree resistance. Numerous warm winters also helped beetles survive and multiply.
The outbreak has sparked debates on forest health and how to manage forests affected by the beetle, where to treat forests and where to log. Some argue that forests should be logged before beetles move in, or to thin stands of dead trees to remove wildfire fuels. Others argue that areas near roads and structures are the only places that need treatment, and will cause the least environmental impact. Studies are finding that conditions created by the beetles aren't all bad.
An infestation begins when a female spruce beetle finds a weak tree and signals to more beetles to attack. The insects chew through the bark and then enter a layer of the tree where they lay eggs in a network of tunnels. The eggs hatch, the beetles grow up and fly away. Before leaving, the mature beetles spread a special fungus in the center of the tree that ultimately kills it.
After the beetle moves on, woodpeckers feed on the larvae left behind, which creates nest cavities in dead trees for other species – such as bluebirds, chickadees and even squirrels – who are unable to make the safe havens themselves.
Then come the wildflowers, which thrive on the exposed understory of the forest, typically covered in shade. Flies and other insects arrive to feed on the flowers, and in turn bring birds, bats and other small mammals, which attract larger predators.
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