Pinus luchuensis
Pinus luchuensis
Pinus luchuensis is an evergreen coniferous tree of the genus pine (Pinus ) with 10 to 15 centimeters long needles and 4 to 5.5 cm long seed cones. The distribution area is located on the Ryukyu Islands of Japan, and extends from sea level to 700 meters. Pinus luchuensis is very wind tolerant and can withstand salty air and sea spray well. The wood is used hardly economically, the species is however used to stabilize coastal sand dunes outside their natural range.
- 5.1 Literature
- 5.2 Notes and references
Description
Habit
Pinus is luchuensis an evergreen, sometimes 15 to 20 feet tall with a trunk diameter of up to 60 centimeters. The Stammborke is gray-brown, rough and scaly and breaks in the lower part in large panels with up to 1 inch deep and 1.5 to 4 cm wide furrows. The bark of young trees and branches of the crown is thin, smooth and gray. The Korkporen are inconspicuous. There are only a few branches of the first order formed, which are usually long and horizontal, where the trees are mostly formed in the natural habitat by the wind. Higher order branches are ascending, and are crowded. They form a shallow, dome-shaped crown in the natural environment. Benadelte branches are bare, more or less smooth and gray.
Buds and needles
The buds are ovate - conical, 10 to 15 mm long, 5-7 mm wide and resinous. The bud scales are pressed, orange or rusty brown. The needles grow in pairs in a lasting, about 10 millimeters long, thin basal needle sheath. The needles are dark green, straight or slightly curved, 10 to 15 centimeters long and 0.7 to 1 millimeter thick semi-circular cross -section, thin, flexible, slightly twisted with finely serrated edges and sharpened. The needle two vascular bundles and two or three central resin ducts are formed. On all sides there are fine needle stomatal lines.
Cones and seeds
The pollen cones grow spirally arranged in groups. They are between 1.5 and 2 inches long, beginning suffused yellow and red and later reddish brown. The seed cones grow singly or sometimes in pairs on short stalks. They are 4 to 5.5 inches long, narrow ovate closed and open diameter from 2.5 to 3 centimeters. The seed scales are dull brown, thinly woody, stiff, oblong, straight or slightly bent open, in the middle of the pin about 2 inches long and 1 inch wide. The apophysis is shiny brown, slightly raised, rhombic or rounded circumference and cross keeled. The umbo is small, reinforced pyramid shaped and with a sharp, pointed sting. The seeds are ellipsoid - ovoid, flattened 4-5 millimeters long and light. The seed leaf is lanceolate, 10 to 15 millimeters long and consistently.
Distribution, ecology and hazard
The natural range of Pinus luchuensis is on the Okinawa Islands and Amami Islands, which belong to the Ryukyu Islands of Japan. Pinus luchuensis is a maritime way up to altitudes of 700 m occurs on the coast of Okinawa and other islands. It grows on sand dunes, rocky foothills and hills, often near the coast to the wind -exposed locations. The species is very tolerant of salt air and salt spray, but also thrives under forest structural conditions without wind and far from the sea. Under natural conditions, it has limited competition and mostly open forms pure stands with little understory of grasses and shrubs, which stabilize the sand. The distribution area is the Hardiness Zone 9 is associated with mean annual minimum temperatures -6.6 to -1.1 ° C ( 20-30 ° F).
The IUCN Red List is led Pinus luchuensis as not at risk ( " Lower Risk / least concern "). It is noted, however, that a reassessment is pending.
Systematics and history of research
Pinus luchuensis is a species in the genus of pine (Pinus ), in which it is assigned to the subgenus Pinus, section Pinus and Pinus subsection. It was founded in 1894 by Heinrich Mayr in About the pines of the Japanese Empire. Supplements to the Central Botanical Journal 58, pp. 148-151 first described scientifically. The genus name Pinus was already used by the Romans for several pine species. The specific epithet is derived from luchuensis Luchu, the former English name of the Ryukyu Islands.
Pinus luchuensis is the Japanese representative of a group of three closely related and very similar species of Pinus taiwanensis to Taiwan and Pinus hwangshanensis from continental China are counted. These species are often either directly attributable to Pinus luchuensis or regarded as varieties or subspecies. Pinus luchuensis differs from Pinus taiwanensis by the longer needles, the lesser number of resin passages ( two to three instead of four to seven ), the shorter pin and the thinner cortex.
Use
Pinus luchuensis has only a small and local importance as a supplier of timber. Due to the tolerance to wind and salty air, it is used to stabilize coastal dunes not only on the Ryukyu Islands but also in other areas of Japan and Taiwan. The species is not used as an ornamental plant cultivars are not known.