Beetles are destroying Washington forests

In the wake of fires and drought comes a new hazard for Washington forests: an opportunist from California that’s boring its way through the state’s already-distressed pine trees.

The California five-spined ips is a species of bark beetle that is endangering forests in the Columbia River Gorge valley.

“It’s pretty unusual to find a bark beetle in a new range,” said Todd Murray, a WSU entomologist and the university’s extension director for Skamania County.

The beetle is typically found in the Sierra Nevada foothills in California, where it flourishes on ponderosa pines. It showed up in Oregon’s Willamette Valley around 1999 and recently appeared in the area from Fort Lewis to Goldendale, where there are many similar trees, Murray said.

Researchers have not seen an outbreak of this type of beetle in the state.

“We’re hoping the outbreak doesn’t continue,” said Glenn Kohler, an entomologist from the Washington Department of Natural Resources. “This would be the fifth year of outbreaks.”

When the ips was first discovered in Washington, researchers checked the bark beetle collections at entomology museums to determine whether the species was previously collected in the state, Kohler said.

“We didn’t expect to see this species so far north causing damage,” Murray said. “As an entomologist it’s hard not to get excited about a new beetle.”

The ips thrives in forests that are stressed due to changes in rainfall patterns, fire and drought. These factors inhibit trees’ natural defenses, which include toxins and pitch that flush the pests out of their bark.

The male ips bores into the tree, where it creates a chamber underneath the bark and emits pheromones to attract females. Females, usually three at a time, come to mate and lay eggs in the chamber, where larvae hatch and feed on the bark.

Murray said the beetles might be moving due to climate change or re-claiming the range they once inhabited.

Researchers are tapping trees across the state to monitor beetle activity and determine the range of the population. They are comparing the five-spined ips to a similar species called the ips pini, a Washington native that Kohler said has undergone numerous recorded outbreaks.

Entomologists are working to combat the infestation by teaching landowners how to deal with the pests. Kohler said the best way to inhibit the beetle population is to avoid piling small branches and pieces of wood, which make perfect breeding grounds.

Landowners should also refrain from working with wood until the beetles’ dormant season, which occurs from late summer to the fall, Kohler said.

“The key is: Don’t make the problem worse than it already is,” Murray said.