Rock Mountain Fir
| Rock Mountain Fir | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Rock Mountain Fir ( Abies lasiocarpa ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Abies lasiocarpa | ||||||||||||
| ( Hook. ) Nutt. |
The rock mountain fir or rock fir ( Abies lasiocarpa ) is a conifer species from the genus of firs ( Abies ). This species is native to western North America , where it occurs from Arizona northwards to the tree line in southern Alaska .
description
Habit and needles
The rocky fir is an evergreen tree . It can reach heights of growth of a good 20 meters, rarely 40 to 50 meters; the trunk diameter can be up to 1 meter, exceptionally up to 2 meters ( BHD ). However, the conifer often also grows as a broad shrub . If you look at the average height, it is the smallest of the eight species of fir native to the western USA.
Due to the adaptation to the different environmental conditions of the natural habitats , five growth forms can be distinguished:
- Very narrow, conical, upright growth with short, stiff branches. This is the typical shape found in most occurrences in the subalpine zone. Open trees retain their lower branches, which often bend down to the ground with age. Trees standing close together become knot-free at about a quarter of the total height.
- A wider, rounded treetop can be found in old specimens in drier locations.
- Mature trees that form a mat close to the ground are seldom found in some areas.
- A flag-shaped crown structure is often found at high locations near the tree line. An upright trunk protrudes over a crooked wood-like mat that spreads out towards the leeward side.
- Krummholz is the typical growth form above the tree line . Due to the cold temperatures and harsh winds, the mountain fir grows dwarf-shaped here in mats close to the ground and is often much wider than it is high.
The first-mentioned typical form with a conical crown usually reaches heights of growth between 18 and 30 meters and trunk diameters between 46 and 61 centimeters. Larger specimens are rather rare.
The rock mountain fir grows slowly; Specimens between 150 and 200 years of age usually have a trunk diameter of only 25 to 50 centimeters. The trees rarely get older than about 250 years because they are very susceptible to stem rot from fungal attack.
The rocky mountain fir is predominantly a shallow root ; However, depending on the nature of the soil, it can also take root.
The bark of young trees is gray and smooth with resin bubbles. The bark of old trees is rough and furrowed or flaky. In the case of the cork fir, the arizonica variety , the bark is cream-colored, thick and corky. The bark of the stiff twigs is green-gray to light brown and only slightly brownish in hair. The buds are partly hidden under the needle dress. The small, almost spherical buds are tan to dark brown and resinous. The basal bud scales are triangular to spatulate.
The needle-shaped leaves are flat, 1.5 to 3 inches long and 1.25 to 2 millimeters wide; they end bluntly. In cross-section, the needles are flat with a notch on the top. They are glossy green on top with a wide stoma stripe, on the underside they have two bluish-white stoma stripes. The needles are spiraling around the branch, but the leaf bases arise mainly on the side of the branch. The needles are tightly packed and some are on top of each other. Fresh leaf scars show a reddish periderm . Crushed needles give off a pungent odor due to β- phellandrenes .
Flowers, cones, miscellaneous
The mountain fir is monoecious . Cones production begins after about 20 years, with the cork fir (variety arizonica ) only after about 50 years.
The male cones are densely clustered in the lower part of the tree canopy on the underside of annual branches. They are purple to purple-greenish in color when ripe.
The female cones stand individually or in smaller groups in the upper part of the tree canopy. They are cylindrical in shape with a rounded tip, 6 to 12 inches long and 2 to 4 inches wide. They are dark purple in color; the 1.5 to 2.5 centimeter long cover scales are densely hairy yellow-brown. The cones stand (as with all fir trees) upright on the branch. They turn brown when ripe in early autumn; as the scales fall off the spindle, the winged seeds are released. The seeds are 6 to 7 millimeters long, 2 to 3 millimeters thick and brown; they have a light brown wing about an inch long. The seeds of the cork fir (variety arizonica ) are 1.7 times larger than this.
The number of cotyledons ( cotyledons ) can vary from 3 to 6; Usually there are 4 or 5. The number of chromosomes is 2n = 24.
Systematics
The rocky mountain fir is classified within the genus of firs ( Abies ) in the Laterales subsection within the Balsameae section .
The description of the taxon Pinus lasiocarpa by the British botanist William Jackson Hooker goes back to 1839. The English botanist Thomas Nuttall classified the species under the taxon Abies lasiocarpa in the genus Abies ; this currently valid description was published in 1849.
In addition to the nominate form, a distinction is made between two varieties:
- Cork fir ( Abies lasiocarpa var. Arizonica (Merriam) Lemmon ; Syn .: Abies lasiocarpa subsp. Arizonica (Merriam) AEMurray ): The description of this variety by John Gill Lemmon was published 1898th It was based on the description published in 1896 by Clinton Hart Merriam under the taxon Abies arizonica Merriam .
- Abies lasiocarpa var. Bifolia (A. Murray bis) Eckenw. (Syn .: Abies subalpina Engelmann , Abies lasiocarpa subsp. Bifolia (A.Murray bis) Silba ): It is also viewed by some authors as a separate species Abies bifolia A.Murray bis . Other authors see it as a synonym of Abies lasiocarpa var. Lasiocarpa .
- Abies lasiocarpa var. Lasiocarpa .
Differentiation of the varieties
In the southeast of the natural distribution area, the nominate form has been partially replaced by its variety Abies lasiocarpa var. Arizonica . This has a cork-like, thick and light-colored bark and blue-gray needles.
The variety bifolia differs from the nominate form in chemical wood properties, the absence of crystals in certain parenchyma , the absence of lasiocarpenonol and the different composition of the terpenes . Other features such as the color of the periderm and the shape of the basal bud scales are also different. Fresh leaf scars show a yellow to barbaric periderm (in lasiocarpa it is reddish). The basal bud scales are narrow-triangular to spatula-shaped (in lasiocarpa they are equilateral triangular). Grated leaves smell somewhat of camphor (with lasiocarpa : pungent odor from β- phellandrenes ). The needles are 11 to 25 millimeters long and 1.25 to 1.5 millimeters wide than those of the lasiocarpa , 18 to 31 millimeters long and 1.5 to 2 millimeters wide.
The arizonica variety is most clearly defined by its rather cream-colored, thick, corky bark, which is dark gray and deeply grooved. Their needles are bluish and shinier than in the nominate form lasiocarpa .
Introgression takes place between the type and the variety bifolia in central British Columbia and northern Washington . In northern central Alberta, introgression of the bifolia variety with the balsam fir ( Abies balsamea ) is observed. The nominate form lasiocarpa probably hybridizes with Abies procera in the southern part of its distribution area . Hybridization with the purple fir ( Abies amabilis ), on the other hand, apparently does not take place despite a large common area of distribution.
Distribution and location
The entire range of the species extends from southern Alaska across Canada ( Yukon , Northwest Territories , British Columbia and Alberta ) to the US states of Washington , Oregon , California , Idaho , Montana , Wyoming , Colorado , New Mexico , Arizona , Utah and Nevada . This makes it the most common type of fir in North America in the north-south direction.
The nominate form Abies lasiocarpa var. Lasiocarpa is native to southern Alaska, Yukon, British Columbia and Alberta and occurs even further south in the Rocky Mountains and the Cascade Mountains and the Olympic Mountains in Washington . The occurrences are mainly located at altitudes from 1100 to 2300 m in subalpine coastal coniferous forests; in most of its locations it advances at altitudes up to the tree line. It is often associated with Abies amabilis , Pinus albicaulis and Tsuga mertensiana .
The variety Abies lasiocarpa var. Arizonica is native to the southern Rocky Mountains in the US states of Arizona, Colorado and New Mexico. It settles at altitudes from 2400 to 3400 m and is associated with Picea engelmannii in large parts of its range .
The occurrences of the Abies lasiocarpa var. Bifolia variety extend from the southern Yukon, the Northwest Territories, Alberta and British Columbia in Canada south to the US states of Washington, Oregon, Idaho, Montana, Wyoming, Colorado, New Mexico, Arizona, Utah and Nevada. It inhabits altitudes of 600 to 3700 m in subalpine coniferous forests. Similar to the nominate form, this variety also reaches the tree line in the majority of its locations. In large areas it is associated with Picea engelmannii .
use
The tree is partly planted as an ornamental tree because of its bluish needles and is also cultivated as a Christmas tree .
The wood of the rock mountain fir is of low density, soft, odorless and easy to work with. It is used to make paper or as lumber. The wood is not weatherproof.
Hazard and protection
The Subalpine Fir is in the red list of the IUCN out "not at risk". It is pointed out, however, that a new check of the risk is necessary.
swell
- Christopher J. Earle: Abies lasiocarpa. In: The Gymnosperm Database. Retrieved February 2, 2011 .
- Richard S. Hunt: Abies lasiocarpa . In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 2: Pteridophytes and Gymnosperms . Oxford University Press, New York / Oxford a. a. 1993, ISBN 0-19-508242-7 (English).
- Richard S. Hunt: Abies bifolia . In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 2: Pteridophytes and Gymnosperms . Oxford University Press, New York / Oxford a. a. 1993, ISBN 0-19-508242-7 (English).
- Ronald J. Uchytil: Abies lasiocarpa. In: Fire Effects Information System. US Department of Agriculture, accessed February 2, 2011 .
Individual evidence
- ↑ Pinus lasiocarpa. In: Germplasm Resources Information Network - (GRIN). USDA, accessed February 2, 2011 .
- ↑ Abies lasiocarpa. In: Germplasm Resources Information Network - (GRIN). USDA, accessed February 2, 2011 .
- ↑ Abies lasiocarpa var. Arizonica. In: Germplasm Resources Information Network - (GRIN). USDA, accessed February 2, 2011 .
- ^ Abies arizonica. In: Germplasm Resources Information Network - (GRIN). USDA, accessed February 2, 2011 .
- ↑ a b c Rafaël Govaerts (Ed.): Abies. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 6, 2019.
- ↑ Abies lasiocarpa in the endangered Red List species the IUCN 2010. Posted by: Conifer Specialist Group, 1998. Retrieved on February 2, 2011th
