Most people call any kind of conifer a ‘pine tree’. Contrary to popular belief, not all conifers look the same. I’m going to teach you some simple tricks to tell the difference between two genera of conifers*: spruces and firs.
Spruces and firs can be easily confused for one another. Spruces can be identified by using the 3 S’s: square, sharp, smelly. If you roll a spruce needle between your fingers, it won’t roll very well because the needles have a square cross section. These needles are short and very sharp, and are arranged spirally around the branch. If you sniff a spruce, it will have strong, sometimes unpleasant odor. One of the most well-known ‘firs’, the Douglas fir, is not actually a fir at all!
Firs can be identified by using the 3 F’s: flat, friendly, fragrant. Fir needles are flat and soft (friendly), unlike the sharp, square needles of spruces, and the needles are attached to the branch with little suction cups. If you sniff a fir, it will have pleasant fragrance. If you have to choose between a spruce and a fir, I recommend the fir.
*A disclaimer: I learned these tricks in Michigan, so they might not hold true everywhere, but they are a good start!
Once you’ve figured out if your Christmas tree is a fir or a spruce, check out these Christmas themed science videos from Alex Dainis (Bite Sci-zed) and Julia Wilde (That’s So Science).