Protecting the ‘Redwoods of the East’: Hemlocks treated on state-owned property

By on March 9, 2016

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Dead hemlocks at the Linville Gorge. Image by B. Heath, NCFS.

Dead hemlocks at the Linville Gorge. Image by B. Heath, NCFS.

The distinctive forests of Western N.C. are prized and enjoyed by many. Evidenced by the fact that Great Smoky Mountains National Park boasts the most visitors of all National Parks, visitors flock to the area to take in mountainous vistas or navigate trails winding through forests and past waterfalls. The area truly is a gem for our state. But over the past decade, it has been changing dramatically. Hemlocks, the most common tree in Great Smoky Mountains National Park and a prominent species throughout the Appalachians, are slowly being killed by an invasive insect, the hemlock woolly adelgid.

The hemlock woolly adelgid was first found in North Carolina in 1995, and by 2010 it was detected in every county with naturally-occurring hemlock. The effects of this insect are profound. Although hemlocks die slowly over many years, it is hard to miss what remains of the trees: giant, gray skeletons that have been dubbed “gray ghosts” by many.

Craig Lawing (left) and Brian Heath (right) apply imidacloprid as a basal bark spray and soil drench, respectively, to hemlock trees on state property.

Craig Lawing (left) and Brian Heath (right) apply imidacloprid as a basal bark spray and soil drench, respectively, to hemlock trees on state property.

Fortunately, select trees can be protected from the insect with pesticides. In 2007, through funding from the U.S. Forest Service, the N.C. Forest Service – Forest Health Branch began to purchase product, train personnel with N.C. Division of Parks and Recreation and N.C. Wildlife Resources Commission, and treat hemlocks on state-owned property. Each agency used their own standards for selecting trees to protect, but factors included safety concerns, removal costs, visibility, accessibility, historical value and chance of success. Since then, more than 10,000 trees have been chemically protected from infestation through this program. The Great Smoky Mountains National Park also implemented a successful treatment plan to treat hemlocks within park boundaries.

Many hope that chemically protecting hemlocks is a stopgap measure until a more sustainable solution is viable. The use of predatory beetles that feed on hemlock woolly adelgid is growing more popular and shows increasing promise for success. In addition, the search for and development of resistant varieties of hemlocks continues.

State-owned properties where hemlocks have been chemically protected from the hemlock woolly adelgid.

State-owned properties where hemlocks have been chemically protected from the hemlock woolly adelgid.

 

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