Pinus occidentalis
Pinus occidentalis at Pico Duarte, Dominican Republic
Pinus occidentalis is an evergreen coniferous tree of the genus pine (Pinus ), usually with 14 to 18 inches long, growing in groups of three to five needles, and 5 to 9 inches long seed cones. The natural range is on Hispaniola, where it is the only naturally occurring pine species. The species is classified as not threatened in the IUCN Red List, but the stocks were severely depleted by overuse.
- 5.1 Literature
- 5.2 Notes and references
Description
Appearance
Pinus occidentalis grows as evergreen, 30 to 40 meter high tree. The stem is erect and reaches a diameter at breast height of 100 to 120 centimeters. The Stammborke is thick, rough and scaly, gray-brown at first and later gray and broken into irregular, more or less square plates that are separated by deep cracks. The branches are horizontal or ascending and are curved at the bottom of the crown and drooping. The crown is open and irregularly oval. Young shoots have only one node, they are hairless, rough by pulvini, frosted in the first year and later brown.
Buds and needles
The vegetative buds are ovate to ovate -oblong, pointed and slightly resinous. Terminal buds are 10 to 15 millimeters long, seitständige buds are smaller. Trained as bud scales Lower leaves are brown, trockenhäutig, thin, pfriemförmig, truant, straight or bent back. The needles grow in threes up to fifth in a lasting, usually from 8 10 to 15 millimeters long, shiny silvery brown and gray-brown under influence of weather needle sheath. The needles are straight or slightly curved, more or less stiff, light green, usually 14 to 18 inches, rare and from 11 to 20 centimeters long and 1.2 to 1.4 mm thick. They remain three years on the tree. The needle edge is finely serrated, the end pointed and pungent. On all sides there are needle stomatal lines. There shall be three to five resin canals.
Cones and seeds
The pollen cones are initially pink yellowish, later yellowish brown, cylindrical and grown from 1.5 to 2.5 inches long with diameters of about 5 millimeters. The seed cones grow near the ends of branches, individually or in pairs to 10 to 20 mm long, straight or curved stems that remain at the fall of the pin. Mature cones are ovate to ovate - conical, straight or curved, almost symmetrical, usually from 4 5 to 9 and rarely up to 11 centimeters long and 3.5 to 6.5 inches wide. They remain several years after the delivery of the seeds on the tree. The 50 to 100 seed scales are thin woody, oblong, straight or curved. The apophysis is slightly elevated, transversely keeled, brown rhombic or pentagonal, glossy or matt dark in outline, radially striated and under influence of weather dull gray. The shed near the spigot base have a curved apophysis. The umbo is increased, often curved and usually reinforced with a 2 to 3 millimeters long sting. The seeds are wrong obovate, flattened, 5-6 mm long and 3-4 mm wide, mottled light brown and gray-brown. The seed wings are wrong ovate or oblong, 12-18 mm long, 4-6 mm wide, ocher colored with black or gray stripes.
Distribution, ecology and hazard
The natural range of Pinus occidentalis is located on the Caribbean island of Hispaniola in Haiti and the Dominican Repuklik.
The species grows in different habitats from lowland to 200 meters up to the slopes of the Pico Duarte and Pico la Pelona to almost 3200 meters. The most extensive pure stands are found in from 900 to 2700 meters, but were now being overused in accessible areas. The distribution area is the hardiness zone 9 attributed with mean annual minimum temperatures between -6.6 ° and -1.2 ° C (20 ° to 30 ° Fahrenheit ). The annual rainfall varies greatly in the main distribution area it is 1200-1600 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 in which at altitudes above 1600 meters can also frost occur, but rarely snow falls.
The soil in lower elevations usually comes from limestone, at higher altitudes in the Cordillera Central, he is acidic, loamy and shallow. One can find the type in different vegetation types, usually they grow on shallow soil, 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 along with bracken ( Pteridium aquilinum ), in areas with frequent fires with different grass species such as grapes oats Danthonia domingensis and various types of Süßgräsergattung Andropogon and again bracken ( Pteridium aquilinum ).
The IUCN Red List is classified as Pinus occidentalis not endangered ( " Lower Risk / least concern "). It is noted, however, that a reassessment is necessary. It is the only one on Hispaniola naturally occurring pine species and their range extended over the whole island. Through overuse has the distribution area, which is about 30,000 square kilometers comprised mainly earlier than monoculture, reduced to less than 5 percent of the value. Due to the political chaos in Haiti in the 1990s, the protective measures of the government were ineffective, leading to a ruthless exploitation of the remaining stocks. The situation in the Dominican Republic is slightly better, but lead also slashing and burning of the fast-growing population for the destruction of forests. The fires also just regenerating surfaces for long periods destroyed because the young trees still could not develop a protective layer against fire Borken and die.
Systematics and history of research
Pinus occidentalis is a species of the genus pine (Pinus ), in which it is assigned to the subgenus Pinus, section and sub-section Trifoliae Austral. She was described in 1788 by Olof Peter Swartz first time scientifically. The genus name Pinus was already used by the Romans for several pine species. The specific epithet occidentalis comes from Latin and means "west ". It thus refers to the west lies seen from Europe circulation area of the Art
Some authors, occurring from Cuba pines are in the Sierra Maestra in Oriente to the east as a variety Pinus occidentalis var maestrensis also Pinus occidentalis assigned or regarded as a separate species Pinus maestrensis. These pines have 15 to 20 centimeters long needles that grow mostly in bundles of three rarely two or four needles. However Aljos Farjon assigns them to the species Pinus cubensis, Pinus occidentalis var maestrensis is thus only a synonym.
Use
Pinus occidentalis is on Hispaniola an important supplier of timber, which was exported to the middle of the 20th century. The wood has a high quality, similar to that of Pinus caribaea and forms every year four alternating bands of light and dark circles depending on the encountered dry and rainy seasons. It is used for the production of telephone poles, fence posts, and boxes and the timber and processed into pulp for the paper industry. Is obtained locally and the resin for further processing.