Welcome to brain stuff from how stuff works a brain stuff, I'm Lauren Vogelbaum. And during the final month of the year, or sometimes much sooner, vast numbers of harvested trees begin their migration indoors, where they are festooned with ribbons, garlands, ornaments, and lights. Although these trees are grown in the spirit of Christmas, they don't magically or genetically aspire to a
perfectly peaked shape. After Christmas trees reach a height of about three to four feet that's around one meter, orchard workers start helping the shape along with a process called shearing. The trees do most of their new growth in the spring, after that starts hardening up. In the summer, workers shear each tree individually with long, sharp knives. The most common types of Christmas tree are douglas for cannon for frasier fur,
and several species of spruce or pine. However, out of these six hundred and thirty species of conifers in the world, the majority don't actually grow in a strictly conical shape, so trimming is a crucial task when growing these specimens meant to become Christmas trees. This pruning process must continue every summer until the trees reach a marketable age, which usually takes six to eight years. So why do Christmas
celebrants demand pyramiddle trees during the holidays. The notions behind much of the world's traditional Christmas decor originated in Northern Europe and particularly Germany, where enduring images and tails from the mid nineteenth century still ensure that sugar plums are dancing for our heads and that our Christmas trees are conical in that part of the world. Evergreen trees are
pyramid shaped for good reason. Each needle leaf layer has a better opportunity to gather sunlight for photosynthesis if the sun isn't blocked by wide top layers. This tiered arrangement allows the trees to shake off heavy snowfall and the wide spaces between branches that the winds whip through without
causing too much damage. Although synthetic Christmas trees don't generally drop needles on the floor or pose a fire damage by drying out, they can't replicate the experience of selecting a Christmas tree, and for a lot of people, it just isn't Christmas without the piney smell of a freshly
cut tree. Millions of consumers agree. According to the National Christmas Tree Association, in a consumer survey revealed that the sales of real Christmas trees outpaced to those of fake trees twenty seven point four million to eighteen point six million. And as they grow and await their moment in the spotlight, these real Christmas trees provide homes for wild birds and animals while storing carbon and generating oxygen. And best of all, the trees are renewable resource. When one is cut, a
new one is planted in its place. Most people who buy real Christmas trees select pre cut versions sold at retail lots, garden centers, and chain stores. Only of those who opt for the real thing go out and cut their own. Today's episode was written by Laurie L. Dove and produced by Tyler Clang. For more on this and lots of other carefully shaped topics, visit our home planet, How Stuff Works dot hum