Temporal range: 49–0Ma 
|Korean fir (Abies koreana) cone and foliage|
Firs (Abies) are a genus of 48–55 species of evergreen coniferous trees in the family Pinaceae. They are found through 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.
They are large trees, reaching heights of 10–80 m (33–262 ft) tall and trunk diameters of 0.5–4 m (1 ft 8 in–13 ft 1 in) when mature. Firs can be distinguished from other members of the pine family by the unique attachment of their needle-like leaves and by their different cones.
Identification of the different 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.
Firs can be distinguished from other members of the pine family by the unique attachment of their needle-like leaves to the twig by a base that resembles a small suction cup.
The leaves are significantly flattened, sometimes even looking like they are pressed, as in A. sibirica.
The leaves have two whitish strips on the bottom, each of which is formed by wax-covered stomatal bands. The upper surface of the leaves usually is uniformly green and shiny, without stomata or only with few at their tips, visible as whitish spots. Some of the species however have the upper surface of leaves dull, gray-green, bluish-gray to silvery, coated by wax with variable number of stomatal bands, and not always continuous. An example species with shiny green leaves is A. alba, and an example species with dull waxy leaves is A. concolor.
The tips of leaves are usually more or less notched (as in A. firma), but sometimes rounded or dull (as in A. concolor, A. magnifica) or sharp and prickly (as in A. bracteata, A. cephalonica, A. holophylla). The leaves of young plants are usually sharper.
Mature cones are usually brown, young in summer can be green, for example:
or purple and blue, sometimes very dark:
- A. fraseri, A. homolepis (var. umbellata green), A. koreana ('Flava' green), A. lasiocarpa, A. nephrolepis (f. chlorocarpa green), A. sibirica, A. veitchii (var. olivacea green). 
- Section Abies (central, south & east Europe, Asia Minor)
- Abies alba—silver fir
- Abies nebrodensis—Sicilian fir
- Abies borisii-regis—Bulgarian fir
- Abies cephalonica—Greek fir
- Abies nordmanniana—Nordmann fir or Caucasian fir
- Abies nordmanniana subsp. equi-trojani—Kazdağı fir, Turkish fir
- Abies nordmanniana subsp. bornmülleriana—Uludağ fir
- Abies pinsapo—Spanish fir
- Abies pinsapo var. marocana—Moroccan fir
- Abies numidica—Algerian fir
- Abies cilicica—Syrian fir
- Section Balsamea (Taiga|boreal Asia and North America, and high mountains further south)
- Abies fraseri—Fraser fir
- Abies balsamea—balsam fir
- Abies balsamea var. phanerolepis—bracted balsam fir
- Abies lasiocarpa—subalpine fir
- Abies lasiocarpa var. arizonica—corkbark fir
- Abies lasiocarpa var. bifolia—Rocky Mountains subalpine fir
- Abies sibirica—Siberian fir
- Abies sibirica var. semenovii—
- Abies sachalinensis—Sakhalin fir
- Abies koreana—Korean fir
- Abies nephrolepis—Khinghan fir
- Abies veitchii—Veitch's fir
- Abies veitchii var. sikokiana—Shikoku fir
- Section Grandis (western North America to Mexico and Guatemala, lowlands in north, moderate altitudes in south)
- Abies grandis—grand fir or giant fir
- Abies grandis var. idahoensis—interior grand fir or giant fir
- Abies concolor—white fir
- Abies concolor subsp. lowiana—Low's white fir
- Abies durangensis—Durango fir
- Abies durangensis var. coahuilensis—Coahuila fir
- Abies flinckii—Jalisco fir
- Abies guatemalensis—Guatemalan fir
- Abies grandis—grand fir or giant fir
- Section Momi (east & central Asia, Himalaya, generally at low to moderate altitudes)
- Abies kawakamii—Taiwan fir
- Abies homolepis—Nikko fir
- Abies recurvata—Min fir
- Abies recurvata var. ernestii—Min fir
- Abies firma—Momi fir
- Abies beshanzuensis—Baishanzu fir
- Abies holophylla—Manchurian fir
- Abies chensiensis—Shensi fir
- Abies chensiensis subsp. salouenensis—Salween fir
- Abies pindrow—Pindrow fir
- Abies ziyuanensis—Ziyuan fir
- Section Amabilis (Pacific coast mountains, North America and Japan, in high rainfall mountains)
- Section Pseudopicea (Sino-Himalayan mountains, at high altitude)
- Abies delavayi—Delavay's fir
- Abies delavayi var. nukiangensis—
- Abies delavayi var. motuoensis—
- Abies delavayi subsp. fansipanensis—
- Abies fabri—Faber's fir
- Abies fabri subsp. minensis—
- Abies forrestii—Forrest's fir
- Abies densa—Bhutan fir
- Abies spectabilis—East Himalayan fir
- Abies fargesii— Farges' fir
- Abies fanjingshanensis—Fanjingshan fir
- Abies yuanbaoshanensis—Yuanbaoshan fir
- Abies squamata—flaky fir
- Abies delavayi—Delavay's fir
- Section Oiamel (Central Mexico, at high altitude)
- Section Nobilis (western U.S., high altitudes)
Uses and ecology
Wood 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. Because this genus has no insect or decay resistance qualities after logging, it is generally recommended for construction purposes as indoor use only (e.g. indoor drywall on framing). This wood left outside cannot be expected to last more than 12 to 18 months, depending on the type of climate it is exposed to. It is commonly referred to by several different names, including North American timber, SPF (spruce, pine, fir) and whitewood.
Nordmann fir, noble fir, Fraser fir and balsam fir are popular Christmas trees, generally considered to be the best for this purpose, with aromatic foliage that does not shed many needles on drying out. Many are also decorative garden trees, notably Korean fir and Fraser fir, which produce brightly coloured cones even when very young, still only 1–2 m (3.3–6.6 ft) tall. Other firs can grow anywhere between 30 and 236 feet (9.1 and 71.9 m) tall. Fir Tree Appreciation Day is June 18.
Firs are used as food plants by the caterpillars 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, pine beauty and the tortrix moths Cydia illutana (whose caterpillars are recorded to feed on European silver fir cone scales) and C. duplicana (on European silver fir bark around injuries or canker).
- Schorn, Howard; Wehr, Wesley (1986). "Abies milleri, sp. nov., from the Middle Eocene Klondike Mountain Formation, Republic, Ferry County, Washington". Burke Museum Contributions in Anthropology and Natural History 1: 1–7.
- Seneta, Włodzimierz (1981). Drzewa i krzewy iglaste (Coniferous trees and shrubs) (in Polish) (1st ed.). Warsaw: Państwowe Wydawnictwo Naukowe (PWN). ISBN 83-01-01663-9.
Philips, Roger. Trees of North America and Europe, Random House, Inc., New York ISBN 0-394-50259-0, 1979.
|Wikimedia Commons has media related to Abies.|
- Abies at The Gymnosperm Database
- Michael P. FRANKIS CONE COLLECTION: Abies at the Arboretum de Villardebelle—images of cones of selected species
- Platt, Karen "Gold Fever" provides descriptions of golden or yellow-leaved Abies cultivars http://www.karenplatt.co.uk