Fir

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 lines on the bottom, each of which is formed by wax-covered stomatal bands. In most species, the upper surface of the leaves is uniformly green and shiny, without stomata or with a few on the tip, visible as whitish spots. Other species have the upper surface of leaves dull, gray-green or bluish-gray to silvery (glaucous), 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.

The way they spread from the shoot is very diverse, only in some species comb-shaped, with the leaves arranged on two sides, flat (A. alba)

Firs differ from other conifers in having erect, cylindrical cones 5–25 cm (2–10 in) long that disintegrate at maturity to release the winged seeds.

In contrast to spruces, even large fir cones do not hang, but are raised like candles.

Mature cones are usually brown, young in summer can be green, for example:

A. grandis, A. holophylla, A. nordmanniana

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

Section Abies is found in central, south, and eastern Europe and 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

Section Balsamea is found in northern 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

Section Grandis is found in western North America to Mexico, Guatemala, Honduras and El Salvador, in lowlands in the north, moderate altitudes in south.

Abies grandis—grand fir or giant fir

Abies grandis var. grandis—Coast grand fir

Abies grandis var. idahoensis—interior grand fir

Abies concolor—white fir

Abies concolor subsp. concolor—Rocky Mountain white fir or Colorado white fir

Abies concolor subsp. lowiana—Low's white fir or Sierra Nevada white fir

Abies durangensis—Durango fir

Abies durangensis var. coahuilensis—Coahuila fir

Abies flinckii—Jalisco fir

Abies guatemalensis—Guatemalan fir

Abies guatemalensis var. guatemalensis

Abies guatemalensis var. jaliscana

Section Momi

Section Momi is found in east and central Asia and the 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

Section Amabilis is found in the Pacific Coast mountains in North America and Japan, in high rainfall areas.

Abies amabilis—Pacific silver fir

Abies mariesii—Maries' fir

Section Pseudopicea

Section Pseudopicea is found in the Sino-Himalayan mountains at high altitudes.

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

Section Oiamel

Section Oiamel is found in central Mexico at high altitudes.

Abies religiosa—sacred fir

Abies hickelii—Hickel's fir

Abies hickelii var. oaxacana—Oaxaca fir

Section Nobilis

Section Nobilis (western U.S., high altitudes)

Abies procera—noble fir

Abies magnifica—red fir

Abies magnifica var. shastensis—Shasta red fir

Section Bracteata

Section Bracteata (California coast)

Abies bracteata—bristlecone fir

Section Incertae sedis

Section Incertae sedis

Abies milleri—(Extinct) Early Eocene

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).

Abies spectabilis or Talispatra is used in Ayurveda as an antitussive drug.