Pine Forest or Oaks? Pine Beetle Infestation Raises Questions About Future of Long Island’s Ecosystem

The southern pine beetle, first found attacking stands of Long Island’s pitch pine forests in the fall of 2014 and encouraged to spread northward in range by warming winter temperatures, has become a perennial problem for foresters on Long Island.

With mild temperatures again this winter, foresters are bracing for another year of active management here, and are now asking existential questions about the future of Long Island’s iconic pine barrens. 

The Central Pine Barrens Joint Planning & Policy Commission held a two-day forum March 8 and 9 with experts on pine beetle management from throughout the country, at Brookhaven National Laboratory and at sites throughout the Central Pine Barrens.

On March 9, the group met at Hubbard County Park in Flanders for a tour of the site of some of the most dramatic pine beetle management on the East End — much of the infestation to date has been farther west, in places like the Rocky Point Pine Barrens State Forest and Wertheim National Wildlife Refuge in Shirley.

Hubbard County Park, which consists of 1,800 acres and includes four creeks along the edge of Flanders Bay — the largest intact coastal wetland on Long Island — was first infested with southern pine beetles in the fall of 2014, and a New York State Department of Environmental Conservation sawyer team cut down thousands of pine trees the following summer to halt the spread of the bug to healthy trees.

The DEC continued its work trying to prevent the beetles from spreading in the summer of 2016. 

DEC foresters Rob Cole and Nate Hudson explained their work to forum attendees on a March 9 walk through the park.

Management of pine beetle infestations begins by classifying trees by how far along the infestation has progressed in stages ranging from 1 (early) to 3 (too late). When an infestation area to be managed is identified, sawyers cut down Stage 1 and 2 trees, leaving the worst trees, Stage 3 trees, standing because the beetles have already left the trees for dead.

They also cut a buffer of 10 feet per .1 acre, up to 50 feet, of healthy trees surrounding the infested area, to disrupt the beetles from being able to follow pheromone trails to find healthy trees.

By felling the trees and leaving them in place, the beetles are cut off from their food source — the sap of the living pine tree — and they often then die from the dampness as the felled trees rot.

“People need to decide what they want to see here. This was pine barrens, but it’s becoming oak barrens,” said Mr. Hudson as he stood in a clearing filled with cut trees. “If there’s no fire activity here, it’s going to be an oak forest.”

“The DEC would rather have pitch pines as an ecosystem. It’s a rare ecosystem,” said Mr. Cole. “As far as i can see, people want a forest, but is pine more important than oak?”

The pitch pines that make up Long Island’s pine barrens are a fire-dependent species. When a fire spreads through the pine barrens, the heat triggers pine cones to sprout and produce new trees. 

But the density of the stands of trees throughout the pine barrens might not be what’s healthiest for the trees, said Mr. Hudson. who described the density of trees here as sort of a “factory farm,” with trees four to five feet apart, with most of their energy produced by the one to two feet of daylight the trees receive at the top of the canopy.

“When that happens, the mortality jumps across. It’s important to look at this from a landscape level,” he said. “This is too dense for vigorous pitch pines, but it’s about average for the Long Island pine barrens. A lot of it is shoulder to shoulder pines.”

Mr. Hudson pointed out that a wide area of the park that had been cut for pine beetle suppression in the summer of 2016 was a sheep pasture a century ago.

In natural succession, in the absence of fire, pine barrens tend to become oak-hickory forests as they enter a new successional phase.

“It’s not insignificant what we are doing here, or what the southern pine beetle is doing here either,” said Mr. Cole.