The Southern Pine Beetle: Not Just a Southern Concern Anymore?
Native to the southeastern United States, the miniscule southern pine beetle is decimating forests and creeping northward
- By Elizabeth Anne Brown
- Wildlife Science
- Jun 25, 2025
A dying canopy (below, in Alabama) can indicate an infestation of the southern pine beetle (above), whose tunneling leads to resin flows (bottom) and eventually tree death.
IN 2024, a plague of tree-devouring pests reached epidemic proportions across parts of the southeastern United States, killing more than 3 million trees in Alabama alone. The culprit? The southern pine beetle: an insect smaller than a grain of rice.
Although the beetle can fly only modest distances, its rapid reproduction lets it cover vast areas quickly: Infestations can spread from tree to tree. The only way to stop the beetles is to cut down a wide buffer of healthy trees around the infested ones. It’s a cripplingly expensive proposition—$400 to $1,500 per tree in Alabama—when hundreds of infested areas crop up at once.
“The last couple years, the beetles are in a pretty aggressive cycle,” says John Bowers, the private lands stewardship program manager for the , a National Wildlife Federation affiliate.
Infestations affect timber plantations, residential neighborhoods, national forests and other protected lands, targeting various species of pine—including the beetle’s meal of choice, the loblolly. And in the Deep South, the loblolly dominates the region’s $125 billion timber industry. In 2024, the beetle’s spring-to-fall life cycle wiped out an estimated 30,000 acres of trees nationwide, the lion’s share in Alabama, says John Nowak, a U.S. Forest Service (USFS) entomologist. That represents a hit of at least $91 million to the timber industries of Georgia and Alabama, according to the states’ forestry commissions.
Even more worrisome, the beetle may not remain a southern problem for long. With climate change expanding its range, recent years have seen serious infestations in Long Island, with beetles trapped as far north as Cape Cod.
From the top down
The first sign of a southern pine beetle infestation is a fading crown, as a pine’s uppermost needles slip from green to yellow to singed red. Look closer and you’ll find popcornlike clusters of pitch on the trunk, as the tree’s immune system attempts to flush the beetles.
But by then, it’s too late. As the beetles burrow labyrinths of tunnels under a tree’s bark, a fungus they carry disrupts the pathways that ferry nutrients and water from root to canopy. Starved of resources, the trees wither and die from the top down. “Once your tree is attacked by southern pine beetles, that tree is dead. It’s over,” Nowak says. “You’re thinking about the rest of your forest at that point.”
Unlike invasive insects that decimate other trees—the , the —the southern pine beetle is native to the Southeast and part of a healthy ecosystem, Nowak says. It typically preys on trees that are already diseased or damaged, such as those struck by lightning. But in certain years, infestations spread to healthy trees, forming what researchers refer to as “spots” of anywhere from three to hundreds of infested trees. The counted 10,253 such spots in 2024.
The Talladega National Forest in Alabama’s Appalachian foothills saw such a virulent infestation last year that forest managers didn’t have the resources to count how many trees were lost, says Eugene Brooks, a USFS silviculturist. All they could do was warn hikers and hunters to be vigilant for falling limbs—and to carry an axe in case they found themselves trapped.
Experts used to believe drought and excessive heat led to surges, as with major eruptions of species such as the engraver beetle. In general, stressed trees are less able to fend off pest attacks. But an analysis by Nowak and colleagues at Clemson University indicates that, for southern pine beetles, outbreaks are more likely where pines are too dense, causing trees to compete for resources and facilitating an easy beetle commute to the next host. “We know that more open stands with less understory competition, more wind flow, more sunlight getting to the ground—those forests are much less susceptible,” Nowak says.
While the timber sector cultivates concentrations of loblollies, the beetle’s spread isn’t fully attributable to contemporary pine production. “Most pine plantations are well managed,” says , a forest health specialist and professor at the University of Georgia. But homeowners may not realize they live in the footprint of an old timber operation that was converted into a neighborhood, she says. Developers see dense trees as a selling point and not a hazard, and homeowners often don’t know to thin.
Even public lands that have been protected for nearly 100 years are battling the results of centuries-old logging, Brooks explains. By the 1930s, when the U.S. government acquired the land that would become Talladega National Forest, the area had been stripped of most of its native oak and hickory. To combat erosion, foresters wanted a fast-growing tree that would put down roots quickly, leading them to plant thousands of loblolly pines. “A lot of the infestations occur [there],” Brooks says.
Seeing the forest for the trees
Experts don’t have a full picture of how surges impact other wildlife, but they do know even closely related species respond differently. For many woodpeckers, southern pine beetle infestations yield an all-you-can-eat buffet. But infestations can be devastating for the red-cockaded woodpecker, a bird listed as threatened under the Endangered Species Act whose feeding style—creating a wall of resin—attracts beetles that can overrun and take out entire trees.
The beetle’s spread also raises concerns for imperiled New England pitch pine forests, home to endangered moth and butterfly species. Since the 2000s, sightings indicate the beetles are creeping northward at a rate of more than 6 miles a year. But accelerated warming could bring the beetles to the great pine forests of Canada as well as the 皇冠体育app官网平台n West sooner than expected, says , a Dartmouth biology professor. “It’s clearly a result of warming in the coldest night of winter,” he says, calling the southern pine beetle one of the best-documented cases of climate change’s impact on an insect range.
Every spring, monitoring stations across the Southeast use pheromones to attract local pine beetles, allowing Ayres and his team to generate a pine beetle forecast for the upcoming season. Ayres sees no reprieve for Alabama in 2025, anticipating southern pine beetle spots again will be “visible from outer space.”
is a science journalist from Alabama.
More from National Wildlife magazine and the National Wildlife Federation:
How Invasive Species Can Wreak Havoc »
Are Entomologists as Endangered as the Insects They Study? »
