Shape is the most important factor affecting Christmas tree selection, followed by needle retention, species, and price, according to M. Elizabeth Rutledge, a graduate student in the Department of Forestry and Environmental Resources at North Carolina State University.

How many of you out there remember your father negotiating over tree shape? None of us either. But Rutledge says that is the case so we'll let it go and assume everyone picks the best tree and then looks at the price tag, rather than the other way around.

Traditionally, Americans have also preferred dense trees, she writes, whereas Europeans have preferred more natural, or "open" trees. Open trees have more space to hang ornaments, holding up to two-thirds more decorations than heavily sheared trees, and tend to weigh less than dense trees, providing advantages for growers and consumers alike.

Rutledge is working to bring us the best of both worlds. The Fraser fir is an example of s tree that has gained popularity among American consumers looking for longer-lasting Christmas trees. Consumers like the Fraser fir for its conical shape, dark green foliage, pleasant aroma, and excellent needle retention.

So researchers (and Christmas tree growers) are working to shape Fraser firs that satisfy those public preferences. Rutledge is the primary author of a recent study of shearing techniques on Fraser fir.

She and her collaborators evaluated the use on Fraser fir of the Top-Stop Nipper (TSN) a four-bladed, hand-held tool used to reduce growth in Christmas trees. They found that the Top-Stop Nipper, when combined with traditional knife shearing or growth regulator treatments, "might offer a method to produce dense trees with minimal shearing or to leave longer leaders to produce a more open "European-style" tree with a layered, natural appearance.

According to the study, published in the April 2008 issue of HortTechnology, use of the Top-Stop Nipper shows promise for tree growers, but "there is so much variation among trees that the effect of the TSN on long-term appearance, quality, and marketability of Fraser firs is yet unknown."

One thing is certain: the battle is not over and Americans can look forward to new advances in producing picture-perfect Christmas trees.