Pinus glabra
Pinus glabra
Pinus glabra is an evergreen coniferous tree of the genus pine (Pinus ) with mostly 4-8 cm long, arranged in pairs needles and 4-7 cm long seed cones. The natural range is located in the southeastern United States. The species is not endangered. It is economical only of minor importance and is hardly used horticulturally.
- 5.1 Literature
- 5.2 Notes and references
Description
Appearance
Pinus glabra grows as evergreen, 30 to 35 meter high tree. The trunk is straight and columnar, reaching a diameter at breast height of up to 100 centimeters. The largest known specimen was measured in 2003 with a height of 47.6 meters, a crown diameter of 21.4 meters and a trunk diameter of 1.2 meters. The Stammborke is thick, gray-brown and gray weather influence. It remains smooth for a long and scaly, later breaks into small, irregular, elongated plates which are separated by shallow furrows. The bark of the branches is gray, smooth and does not flake. The few main branches are horizontal or erect and form in older trees have a rounded or flat crown. The needled branches are thin, reddish brown to purple, glabrous and after the loss of needles by permanent pulvini rough. Young shoots are initially bluish crowded and later gray.
Buds and needles
The buds are ovoid, 5-10 mm long, pointed and slightly resinous. Trained as bud scales Lower leaves are edged with reddish brown and narrow. The needles grow in pairs in an initially 5 to 10 millimeters long later shortening to 3-7 mm needle sheath. They are dark green, stiff, straight, slightly twisted around the longitudinal axis, 4 to 8 inches long and 0.7 to 1.2 millimeters wide and stay two or three years on the tree. The needle edge is finely serrated, pointed the end. On all sides there are needle narrow stomatal lines. There shall be two or three resin canals.
Cones and seeds
The pollen cones grow spirally arranged in small groups. They are short cylindrical, 1 to 1.5 inches long, purplish at first and later brown. The seed cones grow singly or in pairs. They are stalked up to 1 cm long, 4 to 7, rarely long as three or up to 10 inches, closed ovate -oblong and open ovate - cylindrical, initially green and red-brown at maturity. They mature after two years, open wide the seeds leave and then remain three to four years on the tree before they fall together with the stem. The 60-90 seed scales are broadly wedge -shaped, thin woody at the base and more or less flexible. The apophysis is slightly elevated, transversely keeled, in outline, irregularly rhombic or has a rounded upper edge. The umbo is lowered or blunt, unarmed or armed with a weak, decaying little sting. The seeds are obovate to nearly deltoid, 5-6 mm long and brown spotted. The seed wing is 12 to 15 millimeters long.
Chromosome number
The chromosome number is 2n = 24
Branch with needles and seeds journal
Distribution, ecology and hazard
The natural range of Pinus glabra is located in the southeastern United States in Alabama, northern Florida, Georgia, to the east by Louisiana, Mississippi and South Carolina.
The species grows in the temperate warm climate of the lowlands in the southeastern United States at altitudes of up to 150 meters. The summer in the natural range are long, hot and humid, the winters are mild. The distribution area is the Hardiness Zone 8 associated with mean annual minimum temperatures of -12.2 ° and -6.7 ° C (10 ° to 20 ° Fahrenheit ). The trees occur scattered in the river valleys, on river banks, on hills and wetlands on acid subsoil. Young trees usually grow in the shade of deciduous trees as representatives of Magnolia (Magnolia ), the tulip tree ( Liriodendron tulipifera ), the American sweetgum (Liquidambar styraciflua ), with representatives of Tupelobäume ( Nyssa ), the Hickory ( Carya ), the beech (Fagus ) and the oaks (Quercus ), but they exceed the time to height. This shade tolerance is rather uncommon in pine and decreases with plant height, therefore, are often holes in the canopy necessary so that the species can outdo the other trees. Unlike other pine Pinus glabra fire prone. Apart from the deciduous trees they are also found along with Pinus elliottii, the loblolly pine (Pinus taeda ) and the bald cypress (Taxodium distichum).
The IUCN Red List is classified as Pinus glabra not endangered ( " Lower Risk / least concern "). It is noted, however, that a reassessment is necessary.
Systematics and history of research
Pinus glabra 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 Thomas Walter in the Flora Caroliniana first time scientifically. The genus name Pinus was already used by the Romans for several pine species. The specific epithet glabra means bald and refers to the smooth young shoots. The type has no synonyms.
Pinus glabra is similar in the tree form of the Weymouth pine (Pinus strobus ), shoots and needles are similar to those of Pinus echinata, but the needles are darker and the cone scales are less prickly. You can combine with Pinus echinata hybrids, but natural hybrids are not known.
Use
The wood of Pinus glabra has a low quality, it is brittle and not very durable. Along with the scattered occurrence prevents intensive use. Locally it may, if it grows together with other pines, have a certain economic importance as a source of timber. In some areas, it is used as a Christmas tree, but requires frequent cutting in order to achieve the desired shape and branch density. It is rarely used horticulturally outside of botanical gardens and arboretums.