How Do Christmas Trees Achieve Their Shape?

As the year draws to a close — and sometimes even earlier — large quantities of freshly cut trees make their way indoors, where they are adorned with ribbons, garlands, ornaments, and lights.

Although these trees are cultivated with Christmas in mind, they don’t automatically or genetically aim for a flawless peak. "Once the trees reach about 3 to 4 feet (1 to 1.2 meters) in height, we begin a process called 'shearing,'" explained Ben Butler, farm and finance manager of Butler's Orchard in Germantown, Maryland, in an interview with the American Farm Bureau Foundation for Agriculture. "After the trees grow in the spring and their new growth begins to harden off, our crews go through the trees one at a time and help guide the shape of the tree using a very long and sharp knife."

The most popular Christmas tree varieties include Douglas fir, Canaan fir, Fraser fir, and various species of spruce or pine. However, with 630 conifer species globally, most do not naturally grow in a perfect triangular shape. As a result, trimming becomes essential for trees destined to become Christmas trees. This pruning process continues every summer until the trees are ready for market, which typically takes six to eight years.

Take a look at the tree shearing process in this video from Glove Hollow Christmas Tree Farm in Plymouth, New Hampshire:

Historical Tradition

Why do people prefer pyramidal trees for Christmas? The traditions behind much of the world’s Christmas décor trace back to northern Europe, especially Germany, where the iconic imagery and stories from the mid-19th century continue to inspire visions of sugarplums and conical Christmas trees.

In this region, the pyramid shape of evergreen trees has a functional purpose: each layer of needle-like leaves is more efficient at absorbing sunlight for photosynthesis when not obstructed by large top branches. This tiered structure also helps trees shed heavy snow and allows winds to pass through freely, preventing significant damage.

While artificial Christmas trees don’t typically shed needles or pose a fire risk by drying out, they can't replicate the experience of choosing a real Christmas tree. For many, Christmas simply isn’t the same without the fresh pine scent of a newly cut tree.

However, data from 2019 revealed that 82 percent of Americans opt for a fake Christmas tree, while only 18 percent go for the real thing. But perhaps more people should consider the natural option. Real Christmas trees offer shelter to wildlife, help sequester carbon, and produce oxygen. Best of all, they are a renewable resource – when one tree is harvested, another is planted in its place.