They look more like this but the top is usually rounded at maturity.
Fir leaves differ from other fir-like trees, like spruces and doug firs by the way the leaves are attached to the stem. The base of the leaf is rounded and is attached much like suction cups. When the leaves fall off they leave a small rounded or oval circle. You can see that in this image as well.
Branches light reddish brown, stout, and smooth where the leaves have fallen off they will have round scars. The old trunks are smooth as is common of all firs. It is not till they are really old do they become furrowed. Terminal buds are clustered in 3's at the tip, and covered with resin.
Misidentification: look for the very short blue leaves radiating out all around the stem and resinous buds. Foliage is very much different than most firs in that they are really short and plump.
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