Southern pine beetle threatens Pinelands forests

The pest is no larger than a grain of rice, but its voracious appetite is changing the landscape of South Jersey, denuding large patches of the sprawling Pinelands.

Dendroctonus frontalis, the Southern pine beetle, has devoured up to 14,000 acres of pine trees this year in Burlington, Cumberland, Salem, Atlantic, and Cape May Counties - about five times the area affected seven years ago, state officials said.

And the bothersome, oblong-shelled pests show no sign of letting up. They've been found as far north as Monmouth County.

With no dormant period, they eat, reproduce, and spread during even moderate winters.

"This year, the population really took off. It's exploding," said David Finley, regional forester for the Forest Service in the state Department of Environmental Protection.

One reason may be changing weather patterns, Finley said. Warmer winters have allowed the beetles to survive farther north.

At the same time, spring lightning strikes and summer droughts have stressed many trees in the Pinelands' 1.1 million acres. Armies of beetles have overwhelmed the defenses of pines, leaving behind brittle brown needles and skeletal frames.

The insects have been found from New Jersey to Texas and from Arizona to Honduras, federal officials said.

They haven't shown up this year in Pennsylvania, where traps were set to detect them, according to state entomology and forestry officials. In New Jersey, the story is much different.

"It's a serious threat, partly because the terrain is flat," making it easier for the beetles to move to new trees, said Jim Lashomb, a professor of entomology at Rutgers University in New Brunswick.

"There are lots of trees per acre, and their vigor goes down as the roots compete with other trees for water and nutrients," he said. "The drought adds to the stress."

The beetles infest all species of pine, but prefer pitch, shortleaf, pond, and loblolly, which grow across South Jersey. The white pine is not as attractive because its wood is harder and bark thinner.

"It's the resin flow from the trees that dictates the ability to thwart an attack," Lashomb said. If trees "have lots of resin, they can drown [the beetles] right there, but that diminishes when you have a drought."

Southern states have had more experience with the infestation.

"I worked on this in Mississippi when there was an outbreak in 1978," Lashomb said. "We stopped it in certain spots" by harvesting trees and cutting a barrier around the affected area.

"The northern edge of the problem was in Maryland in 1975, with some in Delaware," he said. "When they'd begin moving further north, the cold winters would kill them."

The beetles were detected in New Jersey as early as 1939, but the first significant numbers were noted in 2001, state officials said. Nearly 1,300 acres of pines were destroyed in 2002 and more than 2,500 acres were ruined in 2003.

"We'd find them sticking around Cape May County. Then we noticed them going up the Maurice River and moving north to Monmouth County," Finley said. They've also been seen in Lakewood, Ocean County.

New Jersey forests "are neglected and overstocked," said Bob Williams, a certified forester and consultant for private landowners who discovered the beetle infestation in 2001. "We have a forest health problem."

Williams said the state must better manage the forest by thinning and burning trees so the rest are healthy enough to resist the insects. "If you don't pay for that, then you'll have to pay more for reclamation of the forest," he said.

On the front line of the battle against the beetles is Thomas Hirshblond, a forest technician now cutting down pines in Buena Vista Township, Atlantic County, as a break against the insects.

He's working on a 70-acre property where 20 acres are already dead. He'll cut down about 11/2 acres of infested trees, then create a 21/2-acre buffer to further prevent the spread.

"I know where they are and I have to cut ahead of them," he said Wednesday. "This is some real nice pitch pine - many of them are 80 feet tall - so we really want to stop" these beetles.

With their yellow and reddish hues, damaged trees are easy to spot from the air. Eventually, they turn brown and drop their needles, making the Pinelands more vulnerable to the spread of fire.

The beetles are attracted to trees that have been hit by lightning. "The bark ruptures and the tree boils, and that causes a tremendous flow of attractants in the air," Lashomb said.

"Pheromones from females attract males, and egg galleries are constructed, girdling the trunk," he said.

The beetles and larvae then feed on the cambium, the soft part under the bark, and cut the tree's resin canals. The insects carry a fungus that clogs the tree's vascular system, Finley added.

Getting rid of them is more easily done by Mother Nature than humans. State officials can spray, though that's expensive and difficult, or harvest trees to excise and isolate the problem, as Hirshblond is doing. But what's most efficient in eliminating the beetles is below-freezing temperatures.

"Cold winters kill them and drive them south," Lashomb said. "This won't be over here until we've had a couple good years of cold winters."