Pinus dalatensis
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Pinus dalatensis is a large, evergreen conifer from the genus of the pines ( Pinus ) with needles that grow in groups of five, usually 5 to 10 centimeters long. The seed cones reach a length of 6 to 23 centimeters. The natural range is in Vietnam and Laos. The first description was made in 1960 on specimens that were found near the city of Đà Lạt . Further locations were only discovered in 1999. There are two subspecies and two varieties . Pinus dalatensis is classified as low endangered inthe IUCN Red List .
description
Appearance
Pinus dalatensis grows as an evergreen tree , usually up to 30 and rarely up to 40 meters high. The trunk is straight and columnar and reaches a chest height diameter of up to 2, less often up to 2.5 meters. The trunk bark is initially smooth and reddish brown and later becomes rough and scaly and breaks into small, gray-brown plates. The branches have a smooth bark, spread out widely and shorten over time. The crown is initially conical and, in older trees, broadly dome-shaped or umbrella-shaped. Needled branches are thin and smooth. Young shoots are glabrous or hairy, initially often glaucous or frosted and later pale brown to reddish brown.
Buds and needles
The vegetative buds are small, 6 to 12 millimeters long, conical or egg-shaped, pointed and not resinous. The lower leaves grow pressed and are orange-brown. The needles grow in groups of five in an early sloping, 1 to 1.5 millimeter long, basal needle sheath. The needles are green or glaucous, straight and not pendulous, thin and flexible, rarely from 3, usually 5 to 10 and rarely up to 14 centimeters long and 0.6 to 1, rarely up to 1.2 millimeters wide. The edge of the needle is usually very finely sawn, the end pointed. The two adaxial sides have thin stomata lines . Two resin channels are formed. The needles stay on the tree for two to three years.
Cones and seeds
The pollen cones grow spirally in small groups at the base of young shoots. They are 20 millimeters long, yellow and ovate to short-cylindrical.
The seed cones grow individually or in whorls in twos or threes on strong, 1 to 4 centimeters long, scaly stems, initially erect and hanging when fully grown. They are initially green, when ripe they are matt or shiny brown and resinous. The size of the cones varies greatly, they are between 6 and 23 millimeters long, cylindrical or ellipsoid, straight or curved, and when opened 5 to 9 centimeters wide. The cones open wide, but do not fall off the tree with the stem until some time after the seed has been released. The number of seed scales depends on the size of the cones, Eckenwalder gives the number as around 75. The seed scales are flat or shaped like a boat, thinly woody and flexible. The basal scales grow pressed, only a few are bent back. The apophysis is large, thin or only slightly thickened, more or less rhombic in outline or with a rounded upper (distal) edge, straight or slightly curved, and striped or grooved towards the umbo . The umbo is terminal. It is diamond-shaped, 4 to 10 millimeters wide, recessed, flat or butt protruding.
The seeds and especially the seed wings vary in size similarly to the seed scales. The seeds are a maximum of 8 to 10 millimeters long. The seed wing is 20 to 30 millimeters long, 10 millimeters wide and often dark, longitudinally striped.
Distribution, ecology and endangerment
The natural range of Pinus dalatensis is in the central highlands of Vietnam in the provinces of Binh Tri Thien (now divided into the three provinces Quảng Bình , Quảng Trị , Thừa Thiên-Huế ), Đắk Lắk , Gia Lai , Lâm Đồng and in Laos in the protected area Nakai-Nam-Theun area. The species grows in the mountains at altitudes of 1400 to 2300 meters in the evergreen, tropical forest. The distribution area is assigned to winter hardiness zone 10 with mean annual minimum temperatures between −1.1 and +4.4 ° C (30 to 40 ° F ).
Pinus dalatensis grows in small groups of a few to about 30, according to other sources 300 specimens surrounded by evergreen flowering seeds , mostly representatives of the beech family (Fagaceae) and laurel family (Lauraceae). It often grows on rocky ground and on steep ridges where competition from deciduous trees is less. Under more favorable conditions, for example on flat mountain ranges or in mountain foothills near rivers, it reaches a large, outstanding height. It can be found together with other conifers such as Pinus krempfii , the Fujian cypress ( Fokienia hodginsii ) and in the southernmost part of the central mountains with the broad resin ( Dacrydium elatum ). Pinus dalatensis quickly makes it to the canopy, so it is semi-shade-tolerant. However, the seedlings need a lot of light, so the canopy has to be disturbed for the species to reproduce successfully.
In the Red List of the IUCN is Pinus Dalatensis classified ( "Near Threatened") at risk as low. The range extends over about 20,000 square kilometers, with the species actually occurring in fewer than 10 locations on only about 2000 square kilometers. In addition, the stocks are also falling somewhat. However, this decline is small and the populations are located far from major human settlements and are therefore relatively undisturbed. There is also the possibility of discovering other populations, which is why the species was classified as low endangered and not endangered ("vulnerable"). Until 1999, Pinus dalatensis was only known from one location near the city of Đà Lạt , since then further stocks have been discovered in various provinces significantly further north and another site in Laos in the southern part of the Nakai-Nam Theun reserve. The main threat at lower altitudes and in the south of the range is the conversion of forests into agricultural areas and other infrastructure measures, in other areas the felling of Fujian cypresses ( Fokienia hodginsii ) also endangers the populations of Pinus dalatensis .
Systematics and research history
Pinus dalatensis is a species from the genus of pines ( Pinus ), in which it is assigned to the subgenus Strobus , Section Quinquefoliae , Subsection Strobus . The species was only in 1960 by Yvette de Ferré first described . The generic name Pinus was already used by the Romans for several types of pine. The specific epithet dalatensis refers to the city of Đà Lạt, near which the first specimens were found. John Silba assigned the taxon under the name Pinus wallichiana var. Dalatensis (Ferré) Silba as a variety of the teardrop pine ( Pinus wallichiana ), but this name is only used as a synonym .
Pinus dalatensis is a very variable species. Two subspecies can be distinguished, whereby one is divided into two varieties:
- Pinus dalatensis subsp. dalatensis var. dalatensis : Young shoots have different hairs, the seed cones reach lengths of 6 to 16 centimeters. The distribution area is in Vietnam in the provinces of Binh Tri Thien, Đắk Lắk and in Lâm Đồng in the Chu Yang Sinh massif and in the vicinity of Đà Lạt, and in Laos in the Nakai Nam Theun reserve.
- Pinus dalatensis subsp. dalatensis var. bidoupensis Businský : Young shoots are bare, the seed cones reach lengths of 6 to 16 centimeters. The distribution area is in Vietnam in the province of Lâm Đồng on the Bi Doup .
- Pinus dalatensis subsp. procera Businský (Syn .: Pinus dalatensis var. procera (Businský) Aver. ): Young shoots are usually densely hairy and the seed cones reach lengths of 9 to 23 centimeters. The distribution area is in Vietnam in the province of Gia Lai on the Ngọc Linh , in the Ngok Niay mountains, and in the district of Kon Plong and possibly on the other side of the border in Laos.
One more variety has been added since 2014:
- Pinus dalatensis var. Anemophila (Businský) Aver. (Syn .: Pinus anemophila Businský ): It occurs in central Laos.
use
The wood of Pinus dalatensis is of good quality, but the species is rare and trees are felled more by chance. The wood properties are similar to those of the teardrop pine ( Pinus wallichiana ). The species is not cultivated.
swell
literature
- Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 659-661 .
- James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 425 .
- Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , pp. 487, 607 (reprint from 1996).
Individual evidence
- ↑ a b c d e f g h i Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 659
- ↑ a b c d e f James E. Eckenwalder: Conifers of the World , p. 460
- ↑ Christopher J. Earle: Pinus dalatensis. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed on August 3, 2013 .
- ↑ a b Pinus dalatensis in the Red List of Threatened Species of the IUCN 2013. Posted by: P. Thomas, KL Phan, 2010. Retrieved on August 3, 2013.
- ↑ Pinus dalatensis. In: The International Plant Name Index. Retrieved August 3, 2013 .
- ↑ Exactly: Etymological Dictionary of Botanical Plant Names , p. 487
- ↑ Pinus dalatensis. In: The Plant List. Retrieved August 3, 2013 .
- ↑ a b Rafaël Govaerts (Ed.): Pinus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 24, 2019.
- ↑ a b Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 661
Web links
- Pinus dalatensis at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed August 3, 2013.