Chapel Hill: Opinion

Emerald ash borer: The new invader

Orange County Commission for the Environment

Editor’s note: This is the third in a series of articles by the Orange County Commission for the Environment, a volunteer advisory board to the Board of County Commissioners.

Anyone who drives, hikes, or bikes in Orange County or North Carolina in general will notice invasive, exotic (non-native) plants growing over trees (kudzu, honeysuckle and wisteria), taking over yards (English ivy and vinca), or overgrowing wildflowers and river valleys (stiltgrass and Russian Olive).

It is not as easy to notice at first, but insects and often the fungi they carry can destroy our forests. During the 20th century the majority of chestnut and American elm trees in the U.S. were lost to non-native fungi. Both were important urban shade trees and provided vital forest habitat. Today we are losing spruce, fir and hemlock trees in mountain areas to non-native pests, and new diseases such as West Nile Virus and Asian avian flu are also spreading.

Orange County’s native plants (indigenous species that have evolved within the Piedmont ecosystem) clean our water and air, provide wildlife habitat, and help protect us from floods. However, a small percentage of invasive, exotic plants found here and in other parts of this region threaten the continued existence of our native plants, the quality of habitat for wildlife, and the overall biological diversity of our natural areas.  

These non-native plant species may grow faster, reproduce at a more rapid rate, have a larger reproductive dispersal zone, or be able to tolerate a wider range of environmental conditions than native plants. Our insects often cannot utilize exotic plants, impacting the food chain as a whole and threatening critical ecosystem services such as plant pollination. Invasive plants create monocultures, which do not provide food for native animal species and thus can reduce populations of local animals. 

Many invasive plants in the southeastern U.S. originated in southeastern Asia, due to their similar geographical and environmental conditions. Some invasives were introduced to North America accidentally, while others were brought intentionally as ornamental or decorative varieties. In Orange County our newest invasive exotic species is the Emerald Ash Borer.

Today if you drive north from this area on the interstate highways you will see skeletons of ash trees along many roadways and in forests. These ash trees were killed by this small, green beetle from Asia, first discovered in the U.S. in Michigan in 2002 and first seen in North Carolina in 2013. It drills a U-shaped hole in the tree trunk and destroys the internal bark, quickly killing the tree.

The Emerald Ash Borer has been found in 12 North Carolina counties, and just this year it was discovered in Orange County! North Carolina has established a quarantine that prohibits any parts of the ash tree from being moved outside of the county– including living, dead, cut, or fallen pieces; firewood, green lumber, stumps, roots, branches; and composted and uncomposted chips. The exception is firewood that has been treated by an approved U.S. Department of Agriculture method (in an approved kiln) may be removed from the quarantine area.

You can help stop the spread of invasive species by:

▪ Not transporting firewood or other plant material from ash trees out of Orange County.

▪ Learning to identify and remove invasive plant species, replacing them with species native to the Piedmont.

▪ Minimizing changes to natural habitats, as invasive species tend to thrive in disturbed habitats.

▪ Using certified “weed-free” forage, firewood, hay, mulch, compost, and soil.

▪ Planting only native plants (or non-invasive, non-native species) in your yard and gardens.

▪ Cleaning hiking boots, waders, boats, canoes, trailers, and off-road vehicles to stop the spread of seeds and plant fragments to new locations.

▪ Volunteering to remove invasive species from natural areas in your community.

▪ Reporting any symptomatic activity in ash trees to the NCDA&CS Plant Industry Division hotline at 1-800-206-9333 or by email to

▪ Obeying quarantines to stop the spread of organisms.

▪ Registering your backyard chickens to prevent Asian avian flu at

What’s next

A meeting about this new pest will be held at 9 a.m. Thursday, Aug. 20, at the Orange County Whitted Center, 300 W. Tryon St. in Hillsborough. For more info: