The spread of a burrowing insect that kills pine trees slowed in 2012, according to a report by the state Department of Environmental Protection.

Last year, the southern pine beetle affected only 6,200 acres in New Jersey, compared with 7,000 acres in 2011 and 14,000 acres in 2010, the DEP said in its report released this week. The vast majority of the affected pine forest acreage was in areas of the Pinelands National Reserve south of the Mullica River in Atlantic, Cape May and Cumberland counties.

Pine beetles, which are about the size of a grain of rice, will burrow into a tree just beneath the bark to lay eggs. If too many beetles burrow into one tree, the tunnels cut off water and nutrients to the tree, causing death within a few weeks of the infestation. Forestry experts had thought 2012 would see a significant uptick in the extent of the beetles’ infestation due to a mild winter with few freezing days that typically kill off the insect, which thrives in warmer climates.

State Forester Lynn Fleming said scientists think last year’s decline was tied to rainfall in the summer and fall that allowed the trees to produce more sap, which pushed the beetles out of the trees.

“What we’re keeping an eye on for the winter is will the winter be mild again, or will it get cold enough for it to curtail (the spread of the beetle) come spring,” DEP spokesman Larry Hajna said.

The Southern pine beetle was not seen in New Jersey until about 2001, when trees in parts of Cape May and Cumberland counties began to be affected, Fleming said. Infestation did not seem to be a big problem until 2010, when a combination of drought and intense heat stressed trees such that they were susceptible to the insect.

Two years of wetter-than-average weather, other than a moderate short-term drought that occurred last spring, allowed trees to produce enough sap to keep the beetle from burrowing in, Hajna said. That natural phenomena, combined with the state’s efforts to remove infested trees, are the reason why there is such a significant decline in the number of acres affected, he said.

New Jersey Sierra Club President Jeff Tittel said news of the smaller-than-expected outbreak showed that the infestation is subsiding.

Tittel was originally concerned the infestation would become an excuse to allow logging in the Pinelands and southern New Jersey. He said in a prepared statement that clearing buffers and doing other tree removals in the Pinelands should be placed on hold to preserve forest biodiversity while the infestation is being addressed.

“We should only be cutting trees that are infested and leaving our non-infested, healthy trees untouched," Tittel said.

The state has partnered with Rutgers University, Stockton College and Dartmouth University researchers to better understand how to reduce the pine beetle’s threat. Fleming said state foresters also are looking at how better to manage forests in order to help existing trees remain strong and healthy. Among the ideas could be to selectively remove invasive species that are crowding out native trees, she said.

Great Egg Harbor River Association President Fred Akers said he supports how the state is managing the beetle problem. But, while the efforts to control the beetle infestation by cutting down stands of affected trees was working, Akers said, he wondered whether controlled burns could also be used as an effective tactic.

Fleming said the species most likely to be infested is the pitch pine. The beetle tends to burrow in bark that is higher off the ground, so a prescribed burn would not have a positive effect.

State forestry workers, assisted by several federal programs, have used different methods to fight the infestation on public and private land in the Pinelands region, including hand-cutting affected stands of trees in Atlantic, Burlington and Camden counties. However, in areas south of the Mullica River, particularly in Cape May and Cumberland counties, where larger swaths of trees were affected, the agency had contractors use bulldozers and other equipment to remove trees from state land, Hajna said.

The state estimates that two-thirds of the affected trees are on private, county or municipal-owned property or other land not managed by the DEP, Fleming said.

Atlantic County senior park manager Clayton Ingersoll said there has been some infestation within county park land, with most of the damage occurring in outlying tracts away from more heavily used parcels. “At this point, we really haven’t been able to do much,” Ingersoll said. “We’re monitoring it. We’re putting together a forest management plan. It’s definitely a concern.”

While there is a significant amount of grant money available to private property owners who have beetle infestations, fewer people than expected have applied for them, Fleming said.

“A lot of land owners still don’t understand about the problems. Some don’t want to be bothered,” she said. But unlike oak trees that have had Gypsy moth infestations and will regrow leaves the next year, Fleming said, “when the pine trees lose their needles, they’re not going to come back.”

Contact Sarah Watson:


Follow Sarah Watson on Twitter @acpresssarah