Pinus douglasiana

Pinus douglasiana is an endemic species of the genus in Mexico pines ( Pinus ). This species was in 1943 by Maximino Martinez, a Mexican botanist who first described.

Features

Pinus douglasiana is reached from 50 to 75 cm a tree, plant height of 30 to 35 meters and trunk diameter. The crown is round and dense. The lower branches are horizontal, the upper slightly ascending. Young trees have a dense, pyramidal crown. The bark is reddish brown in old trees, rough, scaly and divided into large, irregular plates. In young leaves, the bark is reddish brown and varies from rough and scaly until smooth. The branches are slender, often slightly pendulous.

The needle leaves are often yellowish green. They are available in bundles of short shoots to fifth; the sheaths are subject to change, not brown and resinous. They are thick, erect, 20-30 cm long. The margin is finely serrated. There are three resin canals present. The hypodermis is formed irregularly. There are two vascular bundles.

The cones are ovoid, the cone scales terminating in a small spine. They are available individually or in groups of two to five in a scaly, short stalk.

The cones are red-brown, egg-shaped and almost symmetrical. They are 7 to 10 cm long. They are on a short stalk, which falls together with the journal. The maturation takes place in winter, the cones open to the maturity and fall soon thereafter. The cone scales are thick, hard, and about 10 mm wide, the apex is irregularly shaped. The apophysis is slightly raised to approximately pyramidal, the umbo is armed sublime and with a small, sloping spine.

The seeds are long, dark brown with 4-5 mm. The seed wing is 25 mm long. The number of cotyledons is usually seven or eight (rarely six to nine ).

The wood is quite firm, rather soft, cream-colored to pale yellow. It is not particularly resinous. It is used as a timber.

Occurrence

Pinus douglasiana is native to Mexico and is found in the central volcanic mountain range that draws on the latitude of Mexico city from west to east through Mexico. However, this area stretches north to the Sierra Madre Occidental and south into the Sierra Madre del Sur. It is known from the following states: Sonora, Chihuahua, Durango, Sinaloa, Nayarit, Jalisco, Michoacán, México, Guerrero and Oaxaca.

This species grows at altitudes from 1500 to 2500 meters under warm to temperate conditions. The rainfall is about 1000 mm per year.

Documents

Jesse P. Perry: The Pines of Mexico and Central America. Timber Press, Portland, 1991, pp. 118ff. ISBN 0-88192-174-2