Pine and spruce beetles on the rise

Although it’s nice to have a break from the cold, the warmer weather leads to more pine and spruce beetles throughout Southern Colorado.

The beetles are to blame for large dead patches of trees commonly seen on the sides of mountains. The insects’ dig small round holes into the bark of the tree’s. This in a sense strangles the tree and kills it.

“You’ve got to imagine the external layers of the bark are what transports nutrients and oxygen up and down the tree,” said Levi Heidrich, co-owner of Colorado Tree Farm and Nursery. “When that layer of bark is damaged, it basically inhibits the tree’s ability to do that.”

The warmer weather is what directly correlates with the insects’ significant increase. Without temperatures dropping to nearly 30 below zero for an extended period of time in the mountains, larva doesn’t die off and in turn this increases the insects population.

“Beetle populations have a longer time where they can feed, they can reproduce more often and we’re not seeing the cold temperatures in the winter that can reduce the populations,” said Damien Zona, silviculturist with the Pikes Peak Ranger District.

Pine and spruce beetles normally don’t go after healthy trees, unless the population numbers increase significantly. “Trees that are stressed release a pheromone or a scent if you will, and those insects home in on that scent and that’s how they know what tree to go after,” said Heidrich.

The beetles are by no means an invasive species here in Colorado. According to the National Forest Service, although devastating in some cases, the beetles do help to thin weak timber out of forests, allowing for healthy trees to grow.

“These are kind of boom and bust cycles periodically and we’re just catching the tail end of a pretty sizable spruce beetle outbreak,” said Zona.