The spruce beetle larvae also introduce a fungus, which spreads into the tree, plugging water and nutrient conduits. And after the insects comes the risk of fire. Insect-killed trees have turned parts of the Medicine Bow National Forest near Laramie Peak into a fire waiting to happen, Anderson said. The problem is unlikely to remain localized. It's bigger than we are.
Infestations can last for more than a decade.
You go there today and you still see all these gray masts. The bug does, however, spare young trees, which spring up to help replace the snags. And in the Routt, at least, only half the trees are spruce. The other half are fir. The mountain pine beetle epidemic is less intense but more widespread.