Pinus douglasiana
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Pinus douglasiana is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). It occurs in Mexico .
description
Vegetative characteristics
Pinus douglasiana is a tree that reaches heights of 30 to 35 meters and a trunk diameter of 50 to 75 centimeters. The crown is rounded and dense. The lower branches are horizontal, the upper ones slightly ascending. Young trees have a dense, pyramidal crown. The bark of old trees is red-brown, rough, scaly and divided into large, irregular plates. In young specimens, the bark is red-brown and varies from rough and scaly to smooth. The branches are slender, often hanging slightly.
The needle leaves stand upright in bundles of five short shoots ; the sheaths are permanent, brown and not resinous. The often yellowish-green needles are relatively thick and 20 to 30 centimeters long. The edge is finely sawn. There are three resin channels. The hypodermis is irregular. There are two vascular bundles . The number of cotyledons is usually seven or eight (rarely six to nine).
The wood is quite firm, rather soft, cream-colored to slightly yellow. It's not particularly resinous.
Generative characteristics
The cones stand individually or in groups of two to five on a scaly, short stem. The cones are egg-shaped, the cone scales end in a small thorn.
The cones stand on a short stalk that drops off together with the cone. The cones are red-brown, with a length of 7 to 10 centimeters egg-shaped and almost symmetrical. Ripening occurs in winter, the cones open to ripeness and fall off soon after. The cone scales are thick, hard, and about 10 millimeters wide with an irregular top. The apophysis is slightly raised to almost pyramidal, the umbo is raised and reinforced with a small, sloping thorn.
The dark brown seeds are 4 to 5 millimeters long. The seed wing is 25 millimeters long.
Occurrence
Pinus douglasiana occurs in Mexico in the central volcanic mountain range, which runs across Mexico from west to east on the geographical latitude of Mexico City. The area stretches north into the Sierra Madre Occidental and south into the Sierra Madre del Sur . It is known from the Mexican states of Sonora , Chihuahua , Durango , Sinaloa , Nayarit , Jalisco , Michoacán , México , Guerrero and Oaxaca .
Pinus douglasiana grows at altitudes of 1500 to 2500 meters. It thrives in warm to temperate climates . The annual rainfall is around 1000 mm.
Taxonomy
The first description of Pinus douglasiana was carried out in 1943 by Mexican botanists Maximino Martinez in Madroño , Volume 7, page 4, panel. 1
use
The wood is used as construction timber.
literature
Jesse P. Perry: The Pines of Mexico and Central America. Timber Press, Portland 1991, pp. 118ff. ISBN 0-88192-174-2 .
Individual evidence
- ↑ Pinus douglasiana at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed April 19, 2019.
Web links
- Data sheet Pinus douglasiana on The Gymnosperm Database .
- Pinus douglasiana inthe IUCN Red List of Threatened Species 2019.1. Listed by: A. Farjon, 2011. Retrieved April 19, 2019.