Abies, commonly known as Fir is a genus of 48 to 55 species of evergreen coniferous tree in the family Pinaceae. They are found throughout much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range. Firs are most closely related to the genus Cedrus (cedar); Douglas-firs are not true firs, being of the genus Pseudotsuga.
All native species reach heights of 30 to 260 feet (10 – 80 m) tall and trunk diameters of 2 to 12 feet (0.5 – 4 m) broad when mature. Firs can be distinguished from other members of the pine family by unique way of attachment of their needle-like leaves and by their different cones.
Identification of the species is based on the size and arrangement of the leaves, the size and shape of the cones, and whether the bract scales of the cones are long and exserted, or short and hidden inside the cone.Attributed from: Wikipedia