CLEMSON — South Carolina officials have declared a statewide emergency quarantine of some wood products due the Emerald Ash Borer (EAB), an invasive insect pest that inhabits and destroys native ash trees.
Under the quarantine, Clemson University officials will regulate the interstate movement of wood and wood products that serve as hosts to the EAB. South Carolina will be added to the U.S. Department of Agriculture’s federal quarantine restricting the interstate shipment of all ash wood and wood products and all hardwood firewood.
“EAB has been gradually progressing across the Eastern United States for 15 years,” said Steve Cole, director of Regulatory and Public Service Programs at Clemson. “At this point, the ecosystem is the greatest consideration. Quarantine will help us slow the spread of the insect to uninfected areas.”
The emergency quarantine will be in place statewide until the legislature can address the issue, Cole said. It covers transportation out of state of the EAB itself as well as nursery stock, green lumber and other material — such as uncomposted chips — from ash trees, the genus Fraxinus. It also applies to firewood of all hardwood (non-coniferous) species.
“We knew it was going to get here eventually. We’ve had a few close calls in North Carolina a mile or two from the border, so we had developed a preliminary plan for dealing with it,” said Steven Long, assistant director of Clemson’s Department of Plant Industry. “Eradication is not possible, but some level of control is. We are pursuing potential methods of biocontrol. There are parasitic wasps that target EAB. There are systemic pesticides you can use on high-value trees. But the reason this pest spreads so fast is that it has no natural predators here.”
The S-shaped galleries (or tunnels) found beneath the bark of an ash that has been infested by the emerald ash borer.
EAB threatens all North American ash trees – a population of about 8.7 billion. It’s already killed an estimated 50 million trees.
Efforts to limit EAB’s scope have affected businesses that sell ash trees or wood products, property owners and governments. Economic impacts are high for urban and residential areas due to the treatment and removal costs, and decreased land value associated with dying trees. Costs for managing these trees often fall on homeowners or local districts.
In addition to implementing quarantines, efforts have been made to service logs of dead, infected trees into lumber and other wood products. Using a specialized heating chamber, researchers at Pennsylvania State University have discovered a way to kill destructive pests, such as the emerald ash border, in wood for pallets and other shipping components.
Ash is known for its staining potential and ability to mimic oak. It has great shock resistance, solid workability, and is low in price. It’s commonly used for tool handles, where toughness is important. The loss of ash from an ecosystem can result in increased numbers of invasive plants, changes in soil nutrients, and effects on species that feed on ash. The loss to an economy can be devastating.
The 8.7 billion ash trees in North America are valued at more than $280 billion. Ash trees are especially abundant in eastern forests, but real diversity is actually in the southwestern U.S., where at least eight of 16 native ash species are present.