Science Behind the Best Christmas Trees

(Inside Science TV) -- About 30 million Christmas trees are sold in the U.S. every year. But when picking the perfect tree, most people have a favorite.

“The most popular tree is the Fraser Fir,” said Byron May, owner of Jordan Lake Christmas Tree farm in Apex, N.C.

There are many different types of trees to choose from. But, growing the perfect tree isn’t easy. Now tree geneticists are working to develop better Christmas trees.

“Some trees are tall, some trees are short. Some of that variation… is due to variation in the genes and how those genes function as the tree grows,” said Ross Whetten, a molecular biologist at North Carolina State University in Raleigh.

“We’re trying to improve the growth rate of these trees so they grow faster, improve their quality. Also more recently, we’ve started looking at needle retention,” said John Frampton, a Christmas tree geneticist at NC State.

A Christmas tree that does not hold its needles is the biggest complaint among consumers. In a lab, researchers test and weigh needles that have fallen off cut Fraser Fir branches after four weeks. Trees are then ranked on how well they retain their needles after being cut. Trees that shed more needles may not be the best for future breeding projects.

“There are some trees that are just genetically predisposed to shed their needles more rapidly and at a greater rate than others,” said Frampton.

Cold weather helps trees hold their needles longer. Soil type and amount of rain can affect trees too. But the best advice to keep your tree looking its best is to “make sure you don’t let the tree go dry…it’s hard to get it to drink again,” said May.

North Carolina ranks number two in the nation for number of harvested Christmas trees. Oregon is number one.

It takes about 5 to 10 years for a Fraser Fir to grow to a Christmas tree height of about 6-7 feet. A Fraser Fir that is not harvested early to be a Christmas tree can grow to between 30 and 50 feet tall.