From 1,000 feet in the air, it’s easy to see just how much damage the southern pine beetle can do to a forest.

As state Department of Environmental Conservation regional forester John Wernet flew over Quogue, wide patches of dead trees could be seen against an otherwise verdant expanse of healthy pine canopy.

“That’s what we don’t want to see,” Wernet said, sitting shotgun in a Cessna owned by the Civil Air Patrol on a beetle-reconnaissance flight last month. “It’s a huge expansion — almost like you dropped a bomb.”

Foresters and land managers have been struggling with how to stanch the spread of the beetle, which has killed thousands of pines on Long Island since it was first confirmed here in 2014.

And as the summer wanes, forest managers are taking stock of how suppression efforts have fared and gearing up for the next round of cutting, typically done in the colder months while the beetles are dormant.

“I think we’re doing everything we can at this point in time,” said John Pavacic, executive director of the Central Pine Barrens Commission.

advertisement | advertise on newsday

His group has a $50,000 state grant that it is using to send interns into the forest to monitor traps and check for infestations, he said. He also plans to hold a research conference on the southern pine beetle early next year.

Pavacic said his group is helping municipalities apply for state grants to help fight the beetle.

Suppression has largely been successful at the Fire Island National Seashore, park biologist Jordan Raphael said.

Last year, 1,200 infested trees had to be cut down on FINS land on Long Island, he said. This year, that number was only 150.

“We seem to have slowed the beetle down at many of the sites,” Raphael said. “We’re still seeing some fresh attacks on new trees. But yeah, promising results so far.”

He said the beetle also appears largely halted in the park’s Sunken Forest — an ecosystem so rare that it is one of only two known in the world.

The beetles, partial to pine trees as their name suggests, overwhelm trees through sheer numbers and kill them within two to four months, according to the DEC.

The beetles spend the warmer months feeding on and killing trees, giving rise to fears that the Island’s signature Pine Barrens could be decimated by the pest.

Experts agree that the best way to slow the insects’ spread is by cutting down infested trees and thinning forests by chopping down healthy trees.

That’s what forest managers have done on several state lands, including at Henry’s Hollow Pine Barrens State Forest in Hampton Bays — one of the areas where the beetle first was discovered on Long Island.

advertisement | advertise on newsday

The DEC cut down thousands of healthy and infested trees there, an expensive but necessary measure.

As the Cessna skirted the edges of Henry’s Hollow, Wernet pointed out the results: The beetles’ tracks had been effectively halted.

“We’re very happy with how it worked,” he remarked. “The suppression was very successful.”

The flight continued over Rocky Point Pine Barrens State Forest, which largely has been spared from the pest.

“So far, so good,” Wernet said from the air.

advertisement | advertise on newsday

About 2,000 dead trees were cut down at four state parks and Bayard Cutting Arboretum, according to the state Parks, Recreation and Historic Preservation Department, while 350 trees were planted at Connetquot River State Park Preserve — one of the state parks hardest hit by the beetle.

Monica Williams, wildlife biologist with the U.S. Fish & Wildlife Service, said about 1,400 infested trees and 2,500 healthy buffer trees have been cut at Wertheim National Wildlife Refuge in Shirley since the beetles were discovered there in 2014.

“Now that we’re getting back into the fall season, we’re going to resume monitoring to see if we have any new infestations,” Williams said.

She said the efforts to date likely have proved worthwhile.

“I think so far it’s helping,” she said. “We don’t know exactly how the beetle will continue to behave. On our property, things are quiet for right now — but that’s for right now.”