Cupressus arizonica

Arizona cypress ( Cupressus arizonica )

The Arizona cypress ( Cupressus arizonica ) is a species of the genus the cypresses (Cupressus ) from the family of the cypress family ( Cupressaceae ). The five varieties are distributed from the southern United States to Mexico.

• 5.1 varieties

Description

Appearance

The Arizona cypress ( Cupressus arizonica var arizonica ) growing as a medium-sized, geradstämmiger, evergreen tree. He attained stature heights of 10 to 20 meters with a diameter at breast height ( DBH ) of up to 80 centimeters. The ovoid - conical canopy is light gray to dark green. The branches are horizontally from the trunk. The stiff and dense branches are uniform, either alternately or opposite, distributed to the branches.

The smooth Arizona cypress ( Cupressus arizonica var glabra) is 7-15 meters high and reaches breast height diameter between 40 and 60 centimeters. The straight stem ends in a densely beasteten to open crown. The crown color varies from gray-green and gray. The branches are, in comparison to Cupressus arizonica var arizonica more vertically from the tribe.

Bark

The bark of Cupressus arizonica var arizonica is depending on the age of different structure and color. In a BHD of up to 15 centimeters and stronger branches, the bark is stained cherry. It is smooth and dissolves into thin rolled, not fibrous plates from the trunk. In a BHD 15-30 centimeters, the bark is dark brown in color. She is thin and consists of irregular square or elongated plates that do not peel off. In a BHD of about 30 centimeters, the bark is fissured lengthwise and dark brown to gray colored you is fibrous and thick and does not flake.

Young trees, thick branches and some old trees of Cupressus arizonica var glabra have a thin and smooth, cherry-red bark from the peels in thin layers or plates. The old trees of this variety have a gray bark sometimes the only places as peels from the trunk.

Wood

The yellowish heartwood differs in color from reddish-brown sapwood. The wood of Cupressus arizonica is textured very light, fine and has a straight grain on. Due to the poor quality it's of little economic importance. The bulk density is 0.48 g / cm ³. The wood has an irregular growth rings closely related to the soil moisture. There are also twice annual rings. Frequently occur in seedlings and branches frost rings.

Foliage

The scale-like leaves are only 2-5 millimeters long. You are keeled or ridged. Cupressus arizonica var arizonica has blue-green colored leaves and a sharply pointed upper end. The expression of the resin glands is highly variable. Cupressus arizonica var glabra has gray -green colored leaves with tapered at the top. The resin glands are well developed in almost all leaves and active. The precipitated resin has a white to dark color.

Flowers, cones and seeds

In the flower morphology is little difference between the varieties. Cupressus arizonica are all monoecious getrenntgeschlechtig ( monoecious ) and marriageable age 4 to 5 years. They develop only female cones in the first 1 to 2 years. The flowering period extends from January to February. The male cones have a length of only 3 to 5 mm and a diameter of 2 millimeters; towards the tip, they are narrower. They are several at the ends of a maximum of 8 to 10 millimeters long spurs. They consist of 12 to 20 ( in Cupressus arizonica var glabra 10 to 18 ) stamens, each with four to six pollen sacs. The female flowers are Zapf terminally on the branches and are thicker than the male spigot flowers. They are enclosed by imbricated cross leaflets. You are in front of pollination about 3 millimeters long and as wide. The scales have ciliated margins. The pivots are spherical to oblong, 20 to 25 mm length and capable of diameter of 20 to 22 mm. You have six or eight (rarely four or ten) seed scales. At first green, the pin with the maturity, 18 to 24 months after pollination, gray or gray - brown. To release the seeds in the fall of the second year after pollination. A pin containing about 90 to 120 seeds.

The thin and winged, dark brown seeds are about 4-5 millimeters long. The exception of a few warty bumps, smooth seed is oval to round as a ball. The wings are about 1 millimeter wide. The thousand-seed weight is 8-9 grams.

Distribution and location

The Arizona Cypress is native to the U.S. states of Arizona, New Mexico and California, and in Mexico in Coahuila, Chihuahua, Durango, Tamaulipas, Zacatecas and northern Baja California. They grow at altitudes between 1000-2900 meters. For accurate dissemination of varieties see systematics.

The Arizona cypress grows in the lower layers of semi-arid mountain ranges with annual rainfall between 250 and 500 mm. The air temperature varies between -17 ° C and above 30 ° C. It occurs on coarse bedload and rich granite and Kalkverwitterungsböden with pH values ​​from 5.5 to 8.3. Sometimes even on clay and sandstone. She is a full sunlight. It is considered a fire- sensitive. It is regarded as insensitive to winter cold and late frosts and drought- resistant than.

In nature, Cupressus arizonica often occurs in small, scattered populations and not in large forests. They often form mixed forests ( spec Qercus. ) With the alligator juniper (Juniperus deppeana ), with the Arizona sycamore (Platanus wrightii ), with Juglans major, with Pinus edulis and various species of oak.

Use

Cupressus arizonica is not used economically due to their low quality wood except as firewood.

The varieties of Cupressus arizonica var glabra and Cupressus arizonica var arizonica are often planted in the U.S. and Europe as ornamental tree and as protection against erosion. It is not suitable for windbreaks because the tribes cast off the lower branches from a certain plant height.

Diseases and Pests

The Arizona cypress is susceptible to infestation with the Lausart Cinara cupressi. An infestation can be recognized by a reddish discolored crown and numerous Dürr branches. The var arizonica is susceptible to the cypress cancer that is triggered by the pathogen Seiridium cardinale, while the var glabra resistant. The type of fungus Phomopsis juniperovora colonized the xylem of branches and causes Astkrebs. The fungus Cercospora sequoidae affects young plants in late summer and leads to browning and drop the leaves and young twigs. Kaba Tina thujae is a type of fungus which a dieback causes that can lead to smaller trees die. The species is resistant to drought, cold and late frosts.

System

It is believed that the varieties are all the result of a once widespread cypress. As the climate changed could not customize the way and survived only in favorable regions. Due to the small population size, geographic isolation and differences in selection pressure developed from this type today's varieties. The classification as varieties is disputed by some authors, but only chemotaxonomic investigations will be able to answer the remaining taxonomic questions. The Mexican Cypress (Cupressus lusitanica ) emerged from the Arizona cypress ( Cupressus arizonica var arizonica ).

Varieties

There are five varieties, which are considered by some botanists as distinct species:

• Arizona cypress ( Cupressus arizonica var arizonica Little). Comes in southern Arizona and southwestern New Mexico, south to Durango and Tamaulipas at altitudes 1200-1800 meters in front. It is cultivated often artificially in Southern Europe.
• Smooth Arizona Cypress (Cupressus arizonica var glabra Little) ( Syn: . C. glabra Sudw ). Occurs at altitudes 1400-2200 meters in Arizona.
• San Pedro Martir - Cypress (Cupressus arizonica var montana Little) (syn.: C. montana Wiggins ). Comes only in San Pedro Mártir in Mexico at altitudes 2200-2900 meters in front.
• Cupressus arizonica var nevadensis Little (syn.: C. nevadensis CBWolf ). Comes in the Sierra Nevada in California at altitudes 1300-2000 meters in front.
• Cuyamaca cypress ( Cupressus arizonica var stephensonii Little) (syn.: C. stephensonii CBWolf ). Comes rare in the Cuyamaca Mountains, in Siskiyou County and Shasta County in California at altitudes 1000-1300 meters in front. The majority of this stock burned in October 2003, the subsequent regeneration was good.

Endangering

The varieties are classified as follows in the IUCN Red List:

• Cupressus arizonica var arizonica is " not at risk " is run as.
• Cupressus arizonica glabra var is not listed in the IUCN Red List.
• Cupressus arizonica var montana is 'at risk' out.
• Cupressus arizonica var nevadensis is considered "at risk " out.
• Cupressus arizonica var stephensonii is considered "at risk " out.

Swell

• Paolo Raddi, Alberto Panconesi: Cupressus arizonica. In: Peter Schütt, Horst Weisgerber, Hans J. Schuck, Ulla Lang, Bernd vocal, Andreas Roloff: Encyclopedia of conifers. Dissemination - description - Ecology - use; the great encyclopedia. Nikol, Hamburg 2004, ISBN 3-933203-80-5, pp. 151-160.
• Christopher J. Earle: Cupressus arizonica. In: The Gymnosperm Database. February 6, 2011, accessed on 27 October 2011 ( English).