Island faces onslaught of Southern pine beetles

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It is smaller than a grain of rice, but an invasive pest from down South has dramatically changed some of the Island’s landscape in the past year, and now threatens to do more damage. 

A scourge of Southern pine beetles arrived on the wind at least a year ago, and already has left some of the Vineyard’s pine forests in ruins. Known as tree killers, the fast-moving beetles are spreading on the Island. 

In one of the worst-hit areas, more than 2,000 pitch pine and white pine trees were infected or deemed at risk at the 69-acre Phillips Preserve, near Lake Tashmoo in Tisbury, and have been cut down and hauled away. 

Damage is also severe at West Chop Woods, a 90-acre coastal pine forest near Vineyard Haven. Both properties are owned by the Sheriff’s Meadow Foundation, a Vineyard conservation group.

“We only noticed last year,” Adam Moore, president of Sheriff’s Meadow, said as he led a Times reporter through Phillips Preserve. “But I think it started much earlier.”

Pine trees on Land Bank properties in Vineyard Haven as well as on private properties in Chilmark also have been affected. 

“It more or less arrived on the western part of the Island and is working its way east,” said Moore, who hasn’t seen any infestations in Edgartown or Oak Bluffs.

So far, the infestation is less severe in the State Forest. Fewer than 10 acres of the 5,000 acres in the forest are infected, according to Nicole Keleher, director of the forest health program for the state Department of Conservation and Recreation.

Crews cut down and removed about 100 infected trees last September after they discovered pockets of reddish-brown treetops in June. Crews also cut additional buffer trees.

They were able to slow the spread because the beetle population was less aggressive than at Phillips Preserve, Keleher said. But an aerial survey flight this spring revealed more trees showing damage from the beetles. They will be cut next week.

In a separate but related problem, a nematode worm has attacked and defoliated beech trees in Cedar Tree Neck Sanctuary and Brookside Ridge Preserve. Unlike Southern pine beetles, beech trees can be treated to get rid of the worms. 

Female Southern pine beetles chew through pine tree bark, carve tunnels inside to lay eggs, and release pheromones to attract males and overwhelm the plant. Thousands of beetles can attack a tree within days. 

The S-shaped tunnels, known as galleries, starve the tree of water. Even 100-year-old trees can die in six weeks. The beetles moved 10 feet per day in the height of summer last year, Moore said.

“In the summer, you can’t really keep up with them, and you don’t want to go through the woods after them with a chainsaw,” he said.

To try to purge the infestation, trees produce pitch tubes of sap that resemble popcorn on the bark. Just as a human body responds to infection with a fever or cold, pitch tubes are a tree’s natural defense against predators. But the effort often fails.

The beetles thrive in the heat, and due to climate change, the pests thrive in the Island’s changing environment of hotter summers and milder winters.

Swaths of pine forests on Long Island were destroyed by Southern pine beetles, and the infestation has spread to the Cape and Nantucket. 

Aerial surveys last summer first revealed the extent of the damage at Phillips Preserve — acres of reddish-brown tops of dead pine trees. Sheriff’s Meadow cut down about 2,000 infected trees to stop the spread, working through the winter and spring. 

Though sections of the preserve are still closed to the public, two contractors from the Cape worked with chainsaws and a feller buncher, a self-propelled logging machine that grabs and cuts trees with shears, on Tuesday to remove the last of the trees earmarked by Moore.

They completed the work just in time. Further cuts are prohibited from June 1 to July 31 because of protected maternity colonies of Northern long-eared bats on the property. The bats roost until mid-summer. Unfortunately, that is when the Southern pine beetles, partial to warmer weather, thrive and do their worst damage.

Trees near the infected trees were thinned out in hopes of stopping the beetles from spreading to still-healthy trees.

“It seems counterintuitive” to remove uninfected trees, Moore said. But the thinned areas act as a buffer to keep the beetles from destroying the rest of the forest. They also allow air to blow around the healthy trees, and give them room to breathe and thus survive.

Moore hopes seeds from the conserved pitch pines will eventually regenerate the forest. Pitch pines grow well in open soil, he said, so regeneration is possible with the increased free space. Some of the trees lost were hundreds of years old, but by next year, younger plants may replace them. 

Oak trees at Phillips Preserve still stand, and Moore said they’ll also respond well to the increased sunlight.

Typically, after a forest is cut or thinned, remnants called slash are left on the ground to rot. But the infestation of Southern pine beetles left so much “fuel on the ground” that it increased the risk of fire, Moore said. 

The blanket of dead and damaged wood on the forest floor at Phillips Preserve forced Moore, an arborist by training, to appeal to the Department of Environment Protection, or MassDEP, for permission to cut the affected trees and burn the infected material with technology that reduces the risk of wildfire. 

The permit, which was approved last week, allows him to conduct “prescribed burn operations using an air curtain burner,” also called a burn box, at Phillips Preserve and West Chop Woods. Burn boxes are often used in California, Montana, and other states susceptible to wildfires. It has never previously been used in Massachusetts. 

The device looks like a big dumpster, Moore said. It holds a self-contained fire, and pushes high-velocity air over the top to create a curtain that prevents smoke and sparks from rising.

Moore has to rent the equipment, and hopes to burn the slash this summer or early fall.

Eventually, Moore would like to use a burner that creates biochar, charcoal from plant matter that removes carbon dioxide from the air. “I think we can get to a point where we conserve all carbon,” he said.

Cut-down trees that are salvageable are milled onsite, and will be used for construction at the new Sheriff’s Meadow headquarters in West Tisbury. 

Slash in the State Forest can be left on the ground. The limited amount doesn’t present the same wildfire danger as at Phillips Preserve, Keleher said.

She said the department would continue to survey and monitor the forest, and respond to any reports of suspicious tree mortality or insect activity. Another two aerial flight surveys are scheduled for the end of June and in the fall.

Moore thinks the Island will need to fight the Southern pine beetle for the next 10 years.

Huge strides were made at Phillips Preserve, he said, but the landscape is much changed. It’s visually akin to a small battlefield; many sections of trees are just gone.

“I personally marked every tree, and thought went into every one,” Moore said, as he shook a can of blue spray paint Tuesday and marked four more trees to be cut.