By Phil Primack
Phil Primack was New Hampshire’s “Outstanding Tree Farmer” in 2024. He is a Medford-based writer.
Two historic copper beech trees — one on the Belmont Town Green and the other at Saugus Iron Works National Historic Site — were felled over the summer. These iconic trees had offered shade and beauty for generations, but they were high-profile losers in an arboreal battle against invasive pests and disease that is reshaping the look and feel of the New England forest.
The pest invasion is widespread. Microscopic roundworms cause beech leaf disease, also known as BLD. The aphid-like woolly adelgid attacks hemlocks. The southern pine beetle, an aggressive bug that reached Massachusetts in 2023, threatens Cape Cod’s signature pitch pine groves. Ash trees have been nearly wiped out by yet another invasive species: the emerald ash borer.
“I do think it’s going to become more obvious that the forest is being transformed,” David Orwig, senior ecologist at Harvard Forest, the 4,000-acre ecological research area in Petersham owned by Harvard University, said in an interview. “We are losing more species, and trees are being killed off more quickly. Adelgid damage to hemlocks was rapid, but beech leaf disease could be even faster.”
The nation’s ever-increasing flow of imports may boost commerce, but all those ships also deliver unintended, six-legged consequences. Drought and other environmental factors wrought by climate change compound the creeping threats to the woods.
“Four years ago, we didn’t see BLD here and now it infects 90 percent of our beech trees,” Orwig said. “Half of our beech trees have maybe 10 leaves left on them.”
The Massachusetts Department of Conservation and Recreation’s 2025 forest health aerial survey confirms BLD’s rapid spread. In 2021, none of the state’s forest canopy was affected; just four years later, BLD had reached 21,582 acres. Not all beeches within those areas will necessarily die, but their prognosis is poor, especially since many are already weakened by beech bark disease, an insect-fungus combination.
The same damage is apparent in the 108-acre tree farm I manage in Epping, N.H. I see the tiny white dots that indicate woolly adelgid and the dark leaf striping that confirms BLD everywhere. The effect extends far beyond the loss of trees. With their thick branches, hemlocks affect the temperature of the ground, and their needles acidify the forest floor. Nutrient-rich beech nuts are a major food source for deer, bears, and other animals. Other trees will replace the lost species — black birch is proliferating in my forest — but they will alter light, temperature, and other conditions of the forest floor, which in turn impact plant, insect, and animal life.
While people like me who spend lots of time with trees are aware of what’s happening, everyone will soon notice. Eastern hemlock and beech comprised about 15 percent of the Massachusetts forest canopy in 2019, according to the US Forest Service. Without them, Robert Frost’s woods may remain lovely — but not nearly so dark and deep.
Tree species have been lost before. Billions of American chestnuts died in roughly five decades due to chestnut blight, an invasive fungus that arrived in the early 1900s. A half century later, tiny wood-boring beetles spread a fungus that devastated the American elm, a favorite street shade tree.
But the scale and spread of the current rapid, multi-species decline may be unprecedented. While some natural phenomena, like extremely cold winters, can slow the pests’ spread, researchers are also experimenting with chemical and biological controls, such as an insecticide that kills woolly adelgid. But such treatments are impractical in large forest stands, where the greater hope may lie with battling bugs. Two years ago, New Hampshire foresters released predatory beetles that feed on the adelgid into my woods. It’s too soon to know who is eating whom.
Because such biocontrols may not succeed, New Hampshire is taking proactive steps to prevent ash tree extinction. State foresters hope to protect and preserve the seeds from 100 stands of healthy, mature ashes. They are also investigating areas where most ashes have died to look for “lingering” ashes, trees that have managed to survive for genetic or other reasons. Material from these trees is then grafted to rootstock at the state forest nursery. The hope is that seeds and sprouts from healthy trees can produce a less vulnerable population.
Massachusetts does not have such an ash propagation program, according to a DCR spokesperson, though department staff regularly use biocontrols on healthy ash and hemlock, with priority given to significant areas like old growth ash trees in the Mohawk Trail area.
“You can say that nature will handle itself, and maybe it will,” said University of New Hampshire forester Greg Jordan, who helped manage my tree farm years ago as a private forester. “If you care about the forest, how do you not address a non-native invasion? In good conscience, we have to try to fight back against these things.”
Those old copper beeches in Saugus and Belmont are gone. Trees that are just sprouts today can offer similar calm and comfort to future generations — if the current one acts now.
