Predators, Weather Will Control Pine Pest

KNOXVILLE — The beetle infestations that are streaking the Cumberland Plateau with brown stands of dead pines will be controlled by natural forces within a couple of years, a University of Tennessee forester said Tuesday.

Populations of the Southern pine beetle are at a peak across the Tennessee Valley because of recent weather patterns, but natural environmental factors should stop the pest after a few seasons, said Dr. Wayne Clatterbuck, a UT assistant professor of forest management.

“We’re in a real population buildup right now, but that population will come back down probably in a year or two, as predators come in and feed on those beetles,” Clatterbuck said.

Woodpeckers and other predators typically increase in the years following an infestation until the beetle population is brought back down to normal levels, he said.

Beetle infestations run on a 10- to 12-year cycle, he said, triggered by injuries to trees, mild winters and summer droughts, he said.

“Beetles attack stressed trees,” Clatterbuck said. “We had ice storms two or three years ago that damaged a lot of trees.”

The red-topped pines visible across the region are already dead from beetle infestations, he said. The wood can be harvested and used for timber or chipping purposes if it is cut quickly enough.

Clatterbuck said the fly-sized beetles bore into the bark of the pines and lay eggs. The larvae then develop and bore out of the bark to find another tree. The beetles live about six weeks, and four to six generations will reach maturity in a year.

“It’s very devastating. The beetles basically cut off the pine tree’s food supply and kill the tree,” he said. “For those folks who have investments in pines, it can be an economic loss.”

Tree farmers can control infestations by harvesting dead trees and thinning out damaged or overly mature pines, he said.