Firs (Abies) are a genus of between 45-55 species of evergreen conifers in the family Pinaceae. All are trees, reaching heights of 10-80 m (30-260 ft) tall and trunk diameters of 0.5-4 m (2-12 ft) when mature. Firs can be distinguished from other members of the pine family by their needle-like leaves, attached to the twig by a base that resembles a small suction cup; and by erect, cylindrical cones 5-25 cm (2-10 in) long that disintegrate at maturity to release the winged seeds. 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. They are most closely related to the cedars (Cedrus). Firs are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range.
Firs are used as food plants by the larvae of some Lepidoptera species including Chionodes abella (recorded on White Fir), Autumnal Moth, Conifer Swift (a pest of Balsam Fir), The Engrailed, Grey Pug, Mottled Umber and Pine Beauty.
Douglas-firs are not true firs, being of the genus Pseudotsuga.
- Section Balsamea (Taiga|boreal Asia and North America, and high mountains further south)
- Section Grandis (western North America to Mexico and Guatemala, lowlands in north, moderate altitudes in south)
- Section Abies (central, south & east Europe, Asia Minor)
- Section Piceaster (southern Spain, northwest Africa)
- Section Momi (east & central Asia, Himalaya, generally at low to moderate altitudes)
- Section Amabilis (Pacific coast mountains, North America and Japan, in high rainfall mountains)
- Section Pseudopicea (Sino-Himalayan mountains, at high altitude)
- Section Oiamel (Mexico, high altitudes in mountains)
- Section Nobilis (western USA, high altitudes)
- Section Bracteata (California coast)
- Section incertae sedis
of most firs is considered unsuitable for general timber
use, and is often used as pulp or for the manufacture of plywood
and rough timber. Nordmann Fir
, Noble Fir
, Fraser Fir
and Balsam Fir
are very popular Christmas trees
, generally considered to be the best trees for this purpose, with aromatic foliage that does not shed many needles on drying out. Many are also very decorative garden trees, notably Korean Fir
and Fraser Fir, which produce brightly coloured cones even when very young, still only 1-2 m (3-6 ft) tall.