The Christmas Tree Conundrum

 The classic Fraser fir is threatened by an invasive insect.

December 20, 2019 

North Carolina grows more Christmas trees than any other state except Oregon.

Drive out into the mountains of western North Carolina and it’s pretty easy to spot one of the state’s biggest cash crops. Christmas trees. North Carolina grows more Christmas trees than any other state except Oregon. That’s almost four million trees per year. Most are sent to Christmas tree lots and stores east of the Mississippi. And that crop of trees which helps create yuletide joy with its green needles generates a lot of green for tree growers—almost $90 million dollars.

Christmas trees are Fraser firs. In many ways they are considered the perfect Christmas tree because the needles are flat, (they don’t stick you as you decorate), the trees don’t shed needles as easily, and the branches are strong which tend to hold ornaments better.

Running a Christmas tree farm isn’t easy and it requires patience. It takes almost ten years before a tree is ready to harvest. And in between the planting and harvest, growers are out with clippers to shape each tree individually as well as fertilize it. They also check for pests such as aphids, mites, or the balsam woolly adelgid. If spotted, the trees are immediately treated with an insecticide. And that is one of the great ironies of the Christmas tree in North Carolina. Fraser firs grow well on the farm but not in the wild and it’s all because of a pest that isn’t supposed to be here.

An exotic pest threatens wild Frasier firs

The balsam wooly adelgid can be controlled on a farm but not in the forest in the wild,” explains Howard Neufeld Ph.D., a biologist who teaches at Appalachian State University and studies the state’s Christmas tree industry. He’s looking at how climate change might affect how and where the trees will grow best because Fraser firs like cooler temperatures. But it’s impossible to ignore the damage the pest has caused.

“It’s had a devastating effect on Fraser firs in the wild,” adds Neufeld. “The balsam woolly adelgid injects a toxin into trees, which triggers as abnormal growth and makes the trees unable to take up water. That eventually kills the tree.”

The adelgid arrived in North Carolina in the early 1900’s. After extensive logging, landowners and government officials decided to replant Mount Mitchell, the highest peak in the Appalachians. The goal was to make the area more suitable for tourists. Trees, including the silver fir were imported from Europe to help accomplish the tourist makeover. Unfortunately, the adelgid hitched a ride on the silver fir. Nobody saw the adelgid because it is extremely small but by the 1970s the damage the pest had done was clear. The Fraser fir was being wiped out.

In some areas, the adelgid has killed almost 90% of the Fraser firs. However, on a few of the highest mountain peaks in the Appalachians, (remember the trees like cooler climates) there are small but healthy stands of spruce-fir forest. Researchers are watching closely to see if these new stands of Fraser fir might have adapted in some way to fight the adelgid. Otherwise, the Fraser firs best chances may be limited to the farm.

—Frank Graff 

 Frank Graff is a producer/reporter with UNC-TV, focusing on Sci NC, a broadcast and online science series.