Difference between "spruce" and "fir" when used in "Christmas tree" context [closed]
Solution 1:
Spruce and fir are different species and are distinguished by different physical characteristics as noted here.
To tell spruce and fir trees apart, it helps to know that spruce needles are sharply pointed, square and easy to roll between your fingers. Fir needles, on the other hand, are softer, flat and cannot be rolled between your fingers. Spruce needles are attached to small, stalk-like woody projections. When needles are shed, these projections remain. As a result, the branches of spruce trees feel rough. Fir branches lack these projections, and thus have smooth bark.
Spruce and fir are distinguished from pine species in that the latter have their needles attached in clusters and the former don't. The term conifer (cone bearing) covers all three.
All of this is likely of interest only to arborolgists. It's hard to imagine that if you announce that you're decorating your Christmas tree that anyone would ask, "Is it an Ables grandis or a Picea orientalis? (That is, fir or spruce?)
Solution 2:
At least in the US, Christmas trees have traditionally been any evergreen conifer (meaning that the leaves are not lost seasonally and cones are the fruiting bodies): pine, fir, spruce, or any of the many others.
The term has even sometimes included other evergreen trees and shrubs besides conifers, as well as artificial trees. It is not the case in the US that a "Christmas tree" is necessarily, or even typically, a fir tree or a spruce tree.