Pacific Island Ecosystems at Risk (PIER)

  [   PIER species lists  ]   [   PIER home  ]

Abies concolor
(Gordon & Glend.) Lindl. ex Hildebr., Pinaceae
Click on an image for links to BIGGER PICTURES


Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Evaluate; score: 1 (Hawaii-Pacific Weed Risk Assessment for Abies concolor)

Other Latin names:  Picea concolor Gordon & Glend.

Common name(s): [more details]

English: Colorado fir, Colorado white fir, silver fir, white fir

Habit:  tree

Description:  "White fir is a large, native, coniferous tree. Mature white fir trees in the central Sierra Nevada are 140 to 180 feet (43-55 m) tall, and 40 to 80 inches (1-2 m) dbh, but may grow larger [104,186]. Rocky mountain white fir rarely exceeds 125 feet (38 m) tall or 3 feet (0.9 m) in diameter [104]. Bark on young trunks is smooth, gray and blistered with resin vesicles, becoming thick, hard and deeply furrowed into scaly ridges with age [71,162]. ¶"The crown of young trees is symmetrical and sharp-pointed, becoming irregular and rounded at the summit [162]. California white fir has a narrow, cylindrical, almost spire-like crown [185,186]. Rocky mountain white fir tends to have a broader crown [185]. White fir branches are short and stout, with leaves 1.2 to 2.8 inches (3-7 cm) long and generally curved upward. Branches are arranged in whorls of 4 or 5, which are repeatedly branched in one plane to form flat, horizontal sprays. Buds are blunt and resinous [71]. In Arizona white fir stands, braches reach nearly to the ground if the trees are widely spaced, and in more dense stands, half or more of the trunk is often bare [162]. ¶"The rooting habit of white fir is usually fairly shallow, but appears to be adaptable to local conditions: deep and intensive where soil conditions permit, to shallow and widespread where rocks or seasonal water tables limit effective soil depth. There is no strong tendency to maintain a single deep taproot although rapid taproot development is critical for survival of new germinants in a dry summer climate. White fir is susceptible to wind throw following partial cutting. Root diseases may contribute to lack of wind firmness. Root grafting between firs is common and is a factor in the spread of root rots [178]. Effects of mycorrhizal associations have been explored and appear to be important in white fir, especially for establishment and early growth on poor sites. It appears that bare mineral soils promote the association [22,178]. ¶"White fir is thought to be a slow growing species [157,178,219]. It can survive for exceptionally long periods as a suppressed tree and still respond to release by increasing growth dramatically. White fir may reach ages of 300-400 years. Old growth characteristics in Southwest are given by [295]. Information on productivity of white fir is available [178,201,263]." (USDA Forest Service Fire Effects Information System: Abies concolor)

See also Trees of North America (pp. 107-109).

Habitat/ecology:  "Abies concolor occurs in the Transition and Canadian Life Zones of high mountains, often restricted to north-facing slopes, at elevations between 600 to 3,000 m in the western part of its range, from 1,800 m to 3,350 m a.s.l. in the Rocky Mountains. It grows in a variety of mountain soils on granitic or basaltic rocks or occasionally sandstone. The climate is moderately humid (500 to 1,875 mm annual precipitation), with relatively warm and dry summers and cold winters. It grows in pure stands, or mixed with various other conifers, e.g. Pinus spp., Abies magnifica, A. procera, A. grandis, Pseudotsuga menziesii var. glauca, and also with Populus tremuloides." (IUCN Red List)

"The trees [PIER ed.: Abies concolor] will grow on a wide range of soils but prefer areas with moist soils, moderately humid climates, and long winters with moderate to heavy snowfall. In the mountains near the Pacific Ocean, the trees occur as low as 700 m (2,300 ft) but normally are found at 1,000-2,500 m (3,200-8,200 ft) and occasionally at 3,400 m (11,000 ft). . . . Bark beetles often attach white fir [PIER ed.: Abies concolor]. Several needle rusts and dwarf mistletoe are the more serious diseases. . . . These long-lived trees grow rapidly for the first 50 years or so and then slowly, often to 350 years of age. . . . The trees do not begin producing cones and seeds util approximately 40 years old and then do not reach optimum seed production for 10 more years. The flowers appear in the spring, and the cones ripen and seeds shed in September or October. On average, heavy seed crops are produced every fifth year, although this period will vary." (Trees of North America, pp. 107-108)

See also Tichá & Úradníček 2014, p. 13.

Propagation:  "White fir reproduction is by seed, and it shows no tendency to reproduce by sprouting or layering. Cuttings can, however, be rooted with or without hormones [178]. White fir is monoecious. The male strobili are 0.2 to 0.4 inches (6-9 mm) long and are densely grouped on the underside of 1-year-old twigs about mid-crown. Female cones are 3 to 5 inches (7-12 cm) long and borne erect on 1-year-old branches, usually in the uppermost crown.

"Cone and seed production: Cone and seed production vary with tree size, age and dominance. White fir trees can begin bearing cones at 40 years and continue beyond 300 years [178]. The best producers are mature, healthy dominants in the 12 to 35 inch (30-89 cm) d.b.h. range [120,178]. Cone production is higher on trees near openings [119] and on trees following release [178]. Immature trees can produce heavy seed crops, but their production is more erratic than that of mature trees [119,178]. Pole-sized trees in dense stands will not produce cones unless their leaders reach full sunlight. In mixed conifer forests of California only 4% of understory white fir between 3.6 and 7.5 inches (9.1-19 cm) in diameter produce cones [104]. In Oregon and California, heavy seed crops in white fir are borne on a 3- to 9- year cycle, with fair to good crops occurring every 2 to 5 years, and bumper crops every 5 to 9 years [178]. In the Rocky Mountains, medium to heavy seed crops are produced every 2 to 4 years [104]. Cone production patterns may be different on extreme sites [110,120,157,178]. Because cones are borne on the uppermost part of the crown, any top damage caused by insects, diseases or mechanical agents (e.g. wind and snow) directly reduces cone production. Cones produce about 185 to 295 seeds apiece [104,119]. Seed numbers can reach 600,000/acre (1.5 million/ha) or more where white fir is a site dominant [112,178], and as many as 220,000 where white fir is a minor overstory component [181].

"Seed predation: Insects that feed on cones and seeds may seriously reduce yield. Seed chalids typically destroy 8 to 10% of white fir seeds and have destroyed up to 60% of a crop [108]. Cone moths, cone midges, and cone maggots also reduce yields [119]. In California and Oregon, the Douglas squirrel cuts and caches cones, but generally takes less than 1% of the cone crop [106].

"Seed dispersal: White fir seeds are released and disseminated by wind as the cone disintegrates on the tree in the fall. Because white fir seed has a short, broad wing relative to its weight, if falls more rapidly and travels a shorter distance from the tree than many of its associated species. Downwind seed spread into an opening is about 1.5 to 2 times the height of the tree [119,178,203]. A small percentage of seeds may be transported greater distances by strong or gusty winds [218].

"Germination: After release in the fall, white fir seeds overwinter in or under the snow. This cold, moist stratification is required for germination [108]. Germination of white fir seeds occurs in the spring immediately following snowmelt. Where snowpack is deep, seeds may germinate in, on, and under the snow [157,178]. Of white fir seeds sown in November in white and red fir stands in the Sierra Nevada, 82 to 86% of all germination occurred by May 9, and 96 to 98% by May 22 [39]. Only a small proportion (20-50%) of seeds are viable [178]. Thus, germination is low, averaging about 37% . Under controlled conditions, white fir seeds may be stored for 5 or 6 years, but under natural conditions seeds do not remain viable over 1 year [108].

"Seedling establishment and survival: White fir seeds that germinate in the snowpack, above the ground, rarely survive, therefore, seeds that fall before the permanent snow cover are more likely to produce seedlings [119]. Germination and early growth are best on bare mineral soil, though seedlings may establish in soils covered by a litter layer [71,100]. Root systems developed in mineral soil without organic layers are longer, heavier, and have more mycorrhizal root tips than those grown in soil with organic layers [22,178]. Seedlings generally establish best in partial shade, and can establish easily under a closed canopy in dense shade [178]. Shade favors seedling survival in white fir because seedlings are very sensitive to soil drying and heating. Damping off fungi, cutworms, drought, heat, trampling and browsing are responsible for most seedling mortality [39,119]. White fir seedlings are more susceptible to spring frost damage and deer browse than many associated species [157,178,219].

"Growth: Once established, white fir grows best in full sun [178]. Shade-tolerant white fir saplings can, however, endure decades of suppression under a closed canopy or in dense brushfields. Leader growth is very slow under these conditions, and suppressed plants may be only 3 feet (0.9 m) tall at 50 years [91]. White fir dramatically increases in diameter and height growth when canopy openings are created, or when its height surpasses surrounding vegetation [100,181]." (USDA Forest Service Fire Effects Information System: Abies concolor)

The trees do not begin producing cones and seeds util approximately 40 years old and then do not reach optimum seed production for 10 more years. The flowers appear in the spring, and the cones ripen and seeds shed in September or October. On average, heavy seed crops are produced every fifth year, although this period will vary." (Trees of North America, p. 108)

Native range:  "White fir occurs from Oregon [PIER ed.: USA] in the Blue Mountains and southern Cascade range, south throughout California and into the San Pedro de Mátir in northern Baja, California; west through parts of southern Idaho, to Wyoming; and south throughout the Colorado Plateau and southern Rocky Mountains in Utah and Colorado, and into the isolated mountain ranges of southern Arizona, New Mexico and northern Mexico [145,310]." (USDA Forest Service Fire Effects Information System: Abies concolor)

See also Trees of North America (p. 107) for additional info & range map.

Impacts and invaded habitats:  (no invaded habitats or impacts known by PIER)

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Pacific
Pacific
Pacific islands not present
Global Invasive Species Database (year unknown)
no results were returned (species not in database) when searching GISD for this species
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Australia (continental) introduced
cultivated
Rowell, Raymond J. (1996) (pp. 5-6)
Japan
Japan
Hokkaido cultivated
northernlight1212 (2015)
Odori Park Street, Sapporo, Japan
New Zealand
New Zealand
South Island introduced
cultivated
bylsand (2017)
ID may be questionable
New Zealand
New Zealand
South Island   Consortium of Pacific Herbaria (2018)
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Europe
Europe
Europe introduced
cultivated
Tichá, Soňa/Úradníček (2014) (p. 13)
"Introduced to Europe in 1873, or maybe even in 1851 according to some data." (p. 13)
United States of America
United States
United States invasive
Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 1)
(X)=present as a weed (but importance rank unknown)

Control:  (control info not known by PIER)

Abies concolor may be tolerant of Payload® herbicide. (Payload 2013)


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

  [   PIER species lists  ]   [   PIER home  ]

This page was created on 12 SEP 2017 and was last updated on 21 MAY 2018.