Pinus densata
Branch
Pinus densata is an evergreen coniferous tree of the genus pine (Pinus ) with 8 to 14 inches long needles and grown 4 to 6 inches long seed cones. The distribution area is located in China, where it grows at altitudes of 2600-4200 meters in the high mountains. There is evidence that it is a natural hybrid between three different pine species. It is not endangered and is hardly used for forestry.
- 5.1 Literature
- 5.2 Notes and references
Description
Habit
Representatives of the species Pinus densata are up to 30 meters high trees with trunk diameters of up to 1.3 meters. The bark is reddish brown at first and later dark gray-brown, scaly and separated into irregularly shaped plates with longitudinal cracks. The branches are spread out and form an ovoid - conical, later broad - ovate or open crown. The branches are stiff, new shoots are bare, rough by pulvini, in the first year shiny yellowish brown, the second and third year of reddish brown.
Buds and needles
The winter buds are dull brown, ovoid - conical and pointed. The terminal buds are about 15 millimeters long with a diameter of 6 millimeters. The bud scales are pointed and have a white toned edge. The needles grow in pairs or rarely in threes in first 10 to 15 millimeters long, later shortening needle sheaths. The needles are straight, 8 to 14 inches long and 1 to 1.5 mm wide, stiff, slightly turned, pointed and dull green. The edges are finely serrated. On each side of the needle, there are fine stomatal lines. The needle three or four resin ducts are formed. The needles remain three years on the tree.
Cones and seeds
The pollen cones grow spirally arranged in groups at the base of new shoots. They are yellowish brown, short - cylindrical, 10-18 mm long and 3 to 4.5 millimeters wide. The seed cones grow singly or in pairs, sessile or stalked very short, closed narrow ovate and 4-6 inches long and 4-7 inches wide open. The seed scales are brown, oblong, thin woody and stiff. The apophysis is significantly increased, 4-7 millimeters thick, clear cross- keeled, more or less rhombic and brilliantly colored chocolate brown. The seeds are ovate to elliptic, 4-6 mm long, light brown to gray- brown. The seed wing is 15 to 20 millimeters long. Pollination is in May, the seed cones mature in October of the second year.
Distribution, habitat requirements and risk
The natural range of Pinus densata located in China in the south of Qinghai in the west of Sichuan, to the northwest of Yunnan and eastern Tibet. It grows in the high mountains at altitudes of 2600-4000 meters or even higher to 4200 meters. About 3000 meters it forms pure stands open, including it grows along with other pines, Pinus armandii and Pinus so with yunnanensis.
The IUCN Red List is led Pinus densata as not at risk ( " Lower Risk / least concern "). It is noted, however, that a reassessment is pending.
Systematics and history of research
Pinus densata is a species of the genus of pine (Pinus ), in which it is assigned to the subgenus Pinus, section Pinus and Pinus subsection. It was first described in 1906 by Maxwell Tylden Masters in the Journal of the Linnean Society Botany. Masters pointed out the similarity with the Japanese red pine (Pinus densiflora ) and Scots pine (Pinus sylvestris ), whose distribution areas are significantly north, however. The physical characteristics of the species are intermediate between those of Pinus yunnanensis, which has a similar distribution area, and the Chinese Pine ( Pinus tabuliformis ) whose distribution area is also located further north. It could therefore be a hybrid of the two species. This is confirmed by genetic studies, where there is evidence of the involvement of an unknown third kind, who disappeared before the Quaternary. Due to the ecological and geographical separation, there is no evidence that new hybrids are formed. The taxon is usually treated as a separate species.
Synonyms of species are Pinus prominens Masters, Pinus sinensis var D.Don densata ( Masters) Shaw, Pinus tabuliformis Carriere var densata ( Masters) Rehder and Pinus wilsonii Shaw (1911 ) not Roezl ( 1857).
The genus name Pinus was already used by the Romans for several pine species. The specific epithet densata derived possibly from the Latin densatio for " thickening " now and could thus refer to the distinctly developed apophysis.
Use
Pinus densata is hardly used economically, since it occurs in rather inaccessible areas only in the high mountains. By the end of the 19th century torches were made from the wood and the resin yet. However, it is considered to use the type of afforestation at high altitudes in western China. Pinus was introduced densata about the turn of the 20th century in Europe, but it is rarely found in botanical gardens and arboretums.