Our hemlock forest is about to change dramatically. The hemlock wooly adelgid (HWA) has arrived and already infests about one-half of the hemlocks in the gorge. It is predicted to infest and kill between ninety and one hundred percent of these most scenic and beneficial trees unless we take action.
HWA
is an aphid-like invader from Asia that appeared on the
Since its initial eastern
HWA is now visible throughout Hickory Nut Gorge. It appears as cotton-like white balls on the underside of hemlock needles when the weather is cold, and is much less visible in summer.
It feeds on, and drains sap from the tree, killing it in 3-5 years from the time of attack. Our hemlocks are extremely important to the beauty and ecology of the gorge.
They provide food and breeding areas for birds and ground animals, roles made more crucial after the American chestnut tree was eliminated by chestnut blight. These trees prevent soil erosion as well as protect and enhance water quality in general and trout streams specifically. The grand and stately presence of the hemlock greatly increases the attractiveness of our natural landscape and thus promotes our tourist-based economy. A recent study showed how HWA and associated hemlock death reduced residential property values in the community studied.
So much for the bad news. Here is the good news. Control of the adelgid is possible and readily available. A common pesticide, imidacloprid, can be spread or injected into the soil around trees or injected into trees directly. Soil “drenching” is the easiest and least costly method currently available and is reported to work very well. Trunk (stem) injection is preferred near streams or ponds to prevent movement of the pesticide into water where it can harm some aquatic animals. With either method the imidacloprid is transported through the roots and trunk to the needles where it is eaten by the HWA. Insecticidal soaps and oils also work but are only practical on smaller trees.
Several species of HWA-eating beetles are being used in some locations with promising results, but more testing is needed. Release of these beetles may become an effective biological control in the future but is not yet readily available or affordable.
A local committee has been formed to help combat HWA. The committee is comprised of members of the Friends of Hickory Nut Gorge and The Upper Broad River Watershed Protection Program. The committee will seek to educate all area land owners about HWA, the scope of the problem, and actions which can be taken to combat this menace. It will also stay in contact with local parks, agencies, and the North Carolina Division of Parks and Recreation with the intent of developing a concerted and meaningful approach to the problem of HWA.
Presently, control of HWA remains very much in the hands of individual landowners. We can not yet save all our trees but we can save many by prioritizing and treating them. You may choose to save those nearest your home, the oldest, or the most beautiful. There are many qualified arborists in the area who can help you survey and examine your trees and treat them with the method of your choice. We recommend using a tree expert unless you plan to use oils or soaps for small or ornamental trees. There is, however, one product available for use by the landowner (Bayer Advanced Tree and Shrub Insect Control). It is unnecessary to treat trees not yet infested.
Please get involved. The natural beauty of the gorge and that of your own property is at stake. Also at stake is the economic health of the gorge and its residential property owners. What’s more, many of the critter species of the gorge will “thank” you as well.
The following is a partial listing of arborists in our region primarily compiled by the Carolina Mountain Land Conservancy:
1.
Frank Varvoutis:
2.
Allen Greene:
3.
Tom Leighty:
4.
Paul O’Neill:
5.
Lee Smith:
6.
7.
Brian Ritter:
Excellent on-line information and resource material is available at many sites including:
Third Symposium on Hemlock Wooly Adelgid in the
Saveourhemlocks.org
Ecoscientificsolutions.com
For questions or comments:
Travis Smith, Chair, Friends of Hickory Nut Gorge smithta@bellsouth.net (828)231-0022
Invasive Species Committee
Clint Calhoun, Upper Broad River Watershed Coordinator (828) 625-9983 (Ext. 123) eco@townoflakelure.com