The Biology of Christmas Trees
Firs, Pines, Spruce, and Cedars are all Different
Real Christmas trees are living plants that grow outside and have distinct characteristics. Growing trees, live trees indoors, and cut trees all have requirements.
It can take up to a decade of growth before an evergreen is ready for Christmas. Various different species are used—they all have natural features that affect their appearance and suitability. It’s interesting to think about the life of the tree that’s so important to us at Christmas.
A Growing Christmas Tree
Once, it was routine for families to go into the woods, find a conical evergreen, cut it down, and bring it home for Christmas. Today, most Christmas trees are grown on tree farms, where they are carefully tended for six to ten years, depending on the type of tree and growing conditions:
- Evergreens need good drainage and the right soil. Some species like sandy soil while others prefer a fine loam. Some trees are very hardy and will grow on land that is not good for other crops.
- Growers watch for signs of disease and insect pests - these can spoil the look of a tree.
- Christmas tree farmers keep weeds away from growing trees - the trees grow faster, have a better shape and tend to be healthier when they don’t have much competition.
- A healthy Christmas tree has an even tapered shape, good colour, and a single straight stem. Extra stems are cut off.
- A cultivated Christmas tree won’t have an entirely natural shape. When they are two thirds of a meter to a meter tall, trees are sheared to improve their shape and to make them bushier.
Characteristics of Different Species of Christmas Trees
Firs, pines, cedar and spruce species are all used as Christmas trees. Everyone has their favorite:
- Firs, like Balsam Fir and Douglas Fir: These evergreens have a typical bushy tapered shape, a nice colour, and a pleasant smell. They hold their needles well; some species have longer needles than others.
- Pines, Scotch (Scots) Pine, White Pine and other species: Pines have a more naturally open look with sturdy upturned branches relatively far apart. They hold their long needles well and have a pleasant smell.
- Spruce, especially the Blue Spruce in North America and the Norway Spruce in Europe: Spruce trees tend to drop their needles quickly, though the Blue Spruce does quite well if it is kept watered. Spruces have a classic Christmas tree shape.
- Cedars, usually the Eastern Red Cedar: Cedars have a typical smell that most people like, however, they tend to have sticky needles that drop quickly.
Biological Needs of a Christmas Tree
The indoor environment is hard on a tree, living or cut. Treat it like a living plant and it will last longer:
- Put it in a cool place away from heaters—these trees are not accustomed to warm temperatures in winter. Bring a live tree indoors slowly so that it can adjust (put it in the garage or an unheated porch for a few days at first).
- Water the tree regularly. For a cut tree, cut the bottom of the trunk off to open the channels and expect the tree to draw up a lot of water at first (if the water dries up for more than four hours, cut the trunk again). Make sure a live tree is damp but not waterlogged.
- Raise the humidity near the tree if possible. There is a commercial spray that prevents loss of moisture and wilting—this can be especially useful with live trees to prevent drying while they are inside.
- Move a live tree back outside, gradually, after seven to ten days.
Related content:
Sources:
“Growing Christmas Trees in Michigan.” Koelling, Melvin and Laurie J. Dornbush
