Pinus occidentalis
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Pinus occidentalis at Pico Duarte , Dominican Republic |
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| Pinus occidentalis | ||||||||||||
| Sw. |
Pinus occidentalis is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). Its natural range is on Hispaniola , where it is the only naturally occurring species of pine.
description
Appearance
Pinus occidentalis grows as an evergreen tree that reaches heights of 30 to 40 meters. The upright trunk stands reaches a diameter of 100 to 120 centimeters at chest height . The trunk bark is thick, rough and scaly, initially gray-brown and later gray, and breaks into irregular, more or less square plates that are separated by deep cracks. The branches are horizontal or ascending and are curved and overhanging in the lower part of the crown. The crown is open and irregularly oval. Young shoots have only one knot , they are hairless, rough due to Pulvini , frosted in the first year and later brown.
Buds and needles
The vegetative buds are ovate to ovate-elongated, pointed and slightly resinous. Terminal buds are 10 to 15 millimeters long, lateral buds are smaller. The lower leaves, which are formed as bud scales, are brown, dry-skinned, thin, awl-shaped , tailed, straight or bent back. The needles grow in groups of three to five in a permanent, from 8 usually 10 to 15 millimeters long, shiny, silvery brown and, when exposed to the weather, gray-brown needle sheath. The needles are straight or slightly curved, more or less stiff, light green, usually 14 to 18 centimeters, rarely from 11 to 20 centimeters long and 1.2 to 1.4 millimeters thick. You stay on the tree for three years. The edge of the needle is finely sawn, the end pointed and piercing. There are stomata lines on all needle sides . Three to five resin channels are formed.
Cones and seeds
The pollen cones are initially yellowish pink, later yellowish brown, cylindrical and fully grown 1.5 to 2.5 centimeters long with a diameter of about 5 millimeters. The seed cones grow near the ends of branches, individually or in pairs, on 10 to 20 millimeter long, straight or curved stems that remain on the cones when they fall. Ripe cones are ovate to ovoid-conical, straight or curved, almost symmetrical, from 4 mostly 5 to 9 and rarely up to 11 centimeters long and 3.5 to 6.5 centimeters wide. They remain on the tree for several years after the seeds have been released. The 50 to 100 seed scales are thinly woody, elongated, straight or curved. The apophysis is slightly raised, transversely keeled, rhombic or pentagonal in outline, shiny or matt dark brown, radially striped and matt gray when exposed to the weather. The scales near the cone base have an arched apophysis. The umbo is raised, often curved and usually reinforced with a 2 to 3 millimeter long spike . The seeds are obliquely obovate, flattened, 5 to 6 millimeters long and 3 to 4 millimeters wide, spotted light brown and gray-brown. The seed wings are obliquely ovate or oblong, 12 to 18 millimeters long, 4 to 6 millimeters wide, ocher-colored with black or gray stripes.
Occurrence and endangerment
Of course, Pinus occidentalis is only found on the Caribbean island of Hispaniola in Haiti and the Dominican Republic.
Pinus occidentalis grows in different habitats from the lowlands at an altitude of 200 meters to the mountain slopes of Pico Duarte and Pico la Pelona at almost 3200 meters. The most extensive pure stands can be found at altitudes of 900 to 2700 meters, which, however, have now been overexploited in accessible areas. The distribution area is assigned to winter hardiness zone 9 with mean annual minimum temperatures between −6.6 ° and −1.2 ° Celsius (20 to 30 ° Fahrenheit ). The annual rainfall varies greatly, in the main distribution area it is between 1200 and 1600 millimeters and exceeds a value of 2300 millimeters in the north and east of the Cordillera Central. In winter there is a three to five month dry season, during which frost can occur at altitudes above 1600 meters , but snow rarely falls.
The soils in lower elevations mostly come from limestone, in higher elevations in the Cordillera Central they are acidic, loamy and shallow. One finds Pinus occidentalis in different types of vegetation , mostly it grows on the shallow, nutrient-poor, often rocky soils, where it occurs in open or dense pure stands, or together with deciduous trees and shrubs. In grazed areas it grows together with bracken ( Pteridium aquilinum ), in areas with frequent fires with different types of grass such as grape oat Danthonia domingensis and different types of the sweet grass genus Andropogon and again bracken ( Pteridium aquilinum ).
In the Red List of the IUCN is Pinus occidentalis "not at risk" (= "Lower Risk / least concern") classified. However, it should be noted that a reassessment is necessary. It is the only naturally occurring species of pine on Hispaniola and its range extended across the island. Due to overexploitation, the distribution area, which previously comprised around 30,000 square kilometers mainly as pure stands, has been reduced to less than 5 percent of the original value. The political chaos in Haiti in the 1990s made the government’s protective measures ineffective, which led to the ruthless exploitation of the remaining stocks. The situation in the Dominican Republic is a little better, but here, too, slash and burn of the rapidly growing population is leading to the destruction of forests. The fires also destroy areas that are regenerating for a long time because the young trees have not yet been able to develop a layer of bark to protect them against fire and they die off.
Systematics
The first publication of Pinus occidentalis was in 1788 by Olof Peter Swartz in Nova Genera et Species Plantarum seu Prodromus , page 103. The specific epithet occidentalis comes from Latin and means "western" and thus refers to the distribution area of this species which is located to the west from Europe.
Species Pinus occidentalis belongs to the Australes subsection from the Trifoliae section in the Pinus sub-genus within the genus ( Pinus ).
Some authors also assign pines occurring in the Sierra Maestra in Oriente in the east of Cuba as a variety Pinus occidentalis var. Maestrensis to Pinus occidentalis or as a separate species Pinus maestrensis Bisse . These pines have needles 15 to 20 centimeters long, which usually grow in bundles of three, less often two or four needles. Aljos Farjon assigns it to the species Pinus cubensis , Pinus occidentalis var. Maestrensis (Bisse) Silba is only a synonym with it .
use
Pinus occidentalis is an important supplier of wood on Hispaniola, which was even exported until the middle of the 20th century. The wood is of a high quality, similar to that of Pinus caribaea and forms four alternating light and dark rings every year, depending on the dry and rainy seasons. It is used in the manufacture of telephone poles , fence posts and boxes and as construction timber and processed into pulp for the paper industry. The resin is also extracted and processed locally .
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literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 725-726 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 457-458 .
Individual evidence
- ↑ a b c d e f g Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 725
- ↑ a b c d James E. Eckenwalder: Conifers of the World , p. 457
- ↑ Pinus occidentalis in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved April 21, 2019.
- ↑ Pinus occidentalis in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed May 19, 2013.
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 725-726
- ↑ a b James E. Eckenwalder: Conifers of the World , pp. 457–458
- ↑ Pinus occidentalis at Tropicos.org. Missouri Botanical Garden, St. Louis, Retrieved April 21, 2019.
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 428 (reprint from 1996).
- ↑ James E. Eckenwalder: Conifers of the World , p. 458
- ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 726
Web links
- Christopher J. Earle: Pinus occidentalis. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed on May 19, 2013 .