Picea breweriana

Brewer spruce (Picea breweriana )

The Brewer Spruce (Picea breweriana ) is a species of the family (Pinaceae ). It is located in the southwestern United States Siskiyou Mountains home.

Description

The Brewer Spruce growing as an evergreen tree that can reach heights of growth of up to 40 meters and diameter at breast height of up to 1.5 meters. The conical crown is formed by overhanging branches with elongated, also drooping, thin branches. Young trees have up to the age of 10 to 20 years no hanging branches. The Stammborke is gray to brown. The gray- brown bark of the branches is covered with fine hair.

The gray-brown buds are 5-7 mm in size and have a rounded tip. The 1.5 to 3 inches long, stiff needles have a blunt tip. Their cross-section is flattened or broadly - triangular, the base is rounded or slightly angular shaped. On the dark green needle top are no Stomatabänder. On the blue-green underside, several, easily identifiable and by small furrows are separated Stomatabänder. The needles are arranged radially on the overhanging branches.

The Brewer Spruce is monoecious ( monoecious ). The dark purple male cones are 1.9 to 3.2 inches long and 1.3 inches thick. Pollination takes place in early summer. The hanging pins are cylindrically shaped with a length of 6.5 to 15 centimeters. They are initially dark red-purple and discolored maturity in the September-October through red to dark brown. The fan-shaped cone scales are 1.5 to 2 inches long and as wide. Its edges are very or somewhat jagged irregular. The seeds are released directly after maturation of the journal.

Distribution and location

The natural, rugged range of the Brewer Spruce is located in the southwestern United States. It is located 22-145 km from the coast and includes the located in northwestern California and southwestern Oregon Siskiyou Mountains. The northern limit of distribution is located at Iron Mountain. During the Miocene and Pliocene of the species was at home in Idaho, Nevada, the central Oregon and the central California.

The Brewer Spruce is a tree species of the maritime -influenced Pacific climate and thrives in high altitude 530-2300 meters. The annual rainfall amount in the western part of the range more than 2800 mm in the eastern part and less than 1000 mm, of which the majority falls in autumn and winter when snow or rain. The species grows on Serpentinböden but also on rocky or poor soils as Entisolen which have formed on ultramafic rocks. One finds the way, especially on ridges and valleys of the subalpine and alpine altitudes, where it grows mainly in forests.

It makes 15 different conifer species mixed stands, most notably the superb fir ( Abies magnifica) and Douglas fir ( Pseudotsuga menziesii ) are particularly common. As some of socialized tree species are larger and older than the Brewer Spruce, this often grows below the crown layer. In mixed stands, which of the Colorado Fir ( Abies concolor), the splendor of fir and mountain hemlock dominated ( Tsuga mertensiana ), the Brewer Spruce occasionally Klimaxbaumart represents the seedlings of the species growing in the undergrowth often together with Arctostaphylos patula, with Quercus sadleriana and with Quercus vaccinifolia. You may also have pure stands, which, however, usually remain small. Because of their vulnerability to forest fires is also often find them as a single tree on rocky, rather lean locations.

Use

Because of their strikingly long, drooping branches, the Brewer spruce is well suited as an ornamental tree and is particularly valued in the UK. Due to the slow growth, the difficulty of this type to grow in culture and the low tolerance to climatic changes, only a few sites are suitable for a successful crop. The wood is hardly used.

Branch with hanging, thin branches

Needles at one end branch

Male cones

Branch with young cones

System

Picea breweriana is within the genre of spruce (Picea ) the subgenus Picea and the Section Omorikae assigned.

The first description as Picea breweriana was made in 1885 by Sereno Watson in Proceedings of the American Academy of Arts and Sciences, Volume 20, page 378 The well-known from the Oligocene of southwestern Colorado, fossil Picea sonomensis Axelrod is regarded as a synonym of Picea breweriana. The specific epithet honors the breweriana, Professor of Agriculture at Yale University, William Henry Brewer, who discovered the species.

Crossing experiments with other pine species such as Engelmann spruce (Picea engelmannii ) and Sitka spruce (Picea sitchensis) were unsuccessful. Molecular studies showed that the Brewer Spruce is probably more closely related within the genus of spruce with any other species and that's it, just like the Sitka spruce, a basal members of this genus.

Threats and conservation

The Brewer Spruce is classified as "low risk" in the IUCN Red List. It is noted, however, that a re-examination of risk is necessary. It is susceptible to fires. A part of the range is located within the Siskiyou National Forest.

Swell

• Christopher J. Earle: Picea breweriana. In: The Gymnosperm Database. www.conifers.org, November 28, 2012, accessed on 21 April 2013 ( English).
• John W. Thieret: Pinaceae. Picea. In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico. Pteridophytes and Gymnosperms. Volume 2, Oxford University Press, New York et al 1993, ISBN 0-19-508242-7, Picea breweriana ( this work is the same text online, Picea breweriana - Online).