Pinus arizonica

from Wikipedia, the free encyclopedia
Pinus arizonica
Pinus arizonia, young tree

Pinus arizonia , young tree

Systematics
Order : Conifers (Coniferales)
Family : Pine family (Pinaceae)
Subfamily : Pinoideae
Genre : Pine ( Pinus )
Subgenus : Pinus
Type : Pinus arizonica
Scientific name
Pinus arizonica
Engelm.

Pinus arizonica is a plant from the genus of pine trees ( Pinus ) within the family of the Pinaceae (Pinaceae). The natural range is in the southwest of the United States and Mexico. It is classified as not endangered inthe IUCN Red List . There are three varieties. It is an important supplier of wood in Mexico and is not used in horticulture.

description

Appearance

Pinus arizonica grows as an evergreen tree that reaches heights of 30 to 35 meters. The trunk grows upright, straight and reaches a diameter of 100 to 120 centimeters at chest height . The trunk bark is thick, rough, scaly and divided into large, gray plates, which are separated by wide and deep, reddish brown to dark brown cracks. The branches are thin and spread out or ascending, lower branches almost drooping. The crown of older trees is rounded or flattened, open or dense. Young twigs are initially orange-brown, covered with a thin layer of wax, bare and rough due to permanent, falling pulvini , remains of fallen needle bundles.

The largest measured specimen in the United States in 1998 reached a height of 38.7 meters with a trunk diameter of 120 centimeters and a crown diameter of 17.3 meters.

Branch with needles

Buds and needles

The lower leaves are dark brown, up to 15 millimeters long and 3 to 4 millimeters wide, awl-shaped , dry-skinned, with an irregularly jagged and ciliate edge and a clipped tip. Vegetative buds are not resinous, brown and ovate to ovate-pointed. Terminal buds are 15 to 30 millimeters long with a diameter of 10 to 15 millimeters, lateral buds are smaller. The bud scales stick out at the tip or are even bent back, they have a brown, long-lashed edge.

The needles grow in groups of three to five in a needle sheath that is initially 15 to 30 millimeters long but shortens to about 10 millimeters. The needles are light yellowish green or bluish green, stiff or soft, straight or slightly curved and twisted, usually 10 to 20, rarely from 8 to 15 centimeters long and 0.9 to 1.8 millimeters thick. The edge of the needle is finely sawn, the end pointed to piercing. On all sides of the needle there are clear stomata , on the convex abaxial side there are usually four to eight, rarely from three to twelve lines, on the two adaxial sides usually four, rarely three or five. Usually three to five, less often up to seven resin canals are formed. The needles stay on the tree for two to three years.

Cones and seeds

The pollen cones are yellowish to yellowish brown, with a length of 15 to 20 millimeters and a diameter of about 5 millimeters, ovoid-oblong to cylindrical. The seed cones grow individually, in pairs or whorls of three to five on short, curved stems. Fully grown cones are almost sessile, ovoid to broadly ovoid, asymmetrical with a slate base, often slightly curved and open, usually 5 to 10, rarely from 4.5 to 14 centimeters long, with diameters of 3.5 to 6 rarely up to 8 centimeters. The 75 to 150 seed scales are thick, stiff, broadly elongated, almost straight or especially curved at the base, dark purple to black-brown on the abaxial side and light brown and slightly spotted on the adaxial side by the seed wings. The apophysis is rhombic to pentagonal in outline, ocher to light reddish brown and keeled transversely. The umbo lies dorsally, it is raised and curved or almost flat, rhombic, transversely keeled, 4 to 8 millimeters wide, gray and reinforced with a small, decrepit spine .

The seeds are obliquely egg-shaped, somewhat flattened, 4 to 7 millimeters long, 3 to 5 millimeters wide, light brown with dark spots. The seed wings are obliquely egg-shaped, 12 to 20 millimeters long, 4 to 8 millimeters wide, translucent and gray-brown with a black tint.

Occurrence and endangerment

Habitus in the habitat at Mount Lemmon , Santa Catalina Mountains

The natural range of Pinus arizonica is in the southwest of the United States in Arizona and New Mexico , and in Mexico in the Sierra Madre Occidental to the south of Durango and scattered in Coahuila , in the northeast of Zacatecas and in Nuevo León .

Pinus arizonica grows at altitudes of mostly 2000 to 2700 meters (1300 to 3000 meters). The distribution area is assigned to winter hardiness zone 7 with mean annual minimum temperatures between −17.7 and −12.3 ° Celsius (0 to 10 ° Fahrenheit ). Light winter frosts can occur in the distribution area. The annual rainfall is low to moderate, ranging from 700 to 900 millimeters, most of which falls over the winter months. It grows on different types of soil, preferably in valleys and on mesas with deep soils. Pinus arizonica grows in pure stands or more often together with various oak species ( Quercus spp.), Other pine species such as Pinus engelmannii and Pinus strobiformis or junipers such as Juniperus flaccida in lower altitudes and Juniperus deppeana in higher areas.

In the Red List of the IUCN is Pinus arizonica "not at risk" (= "Lower Risk / least concern") classified. It should be noted, however, that a reassessment is pending. The species is an important part of the pine and mixed forests of the Sierra Madre Occidental and is heavily used because of the wood, especially in the more accessible areas. Large tree populations are now rare in these areas, but there is no evidence that the range or number of trees is decreasing.

Systematics and research history

It was first described by George Engelmann in 1879 in Joseph Trimble Rothrock : Report Upon United States Geographical Surveys West of the One Hundredth Meridian, in Charge of First Lieut. Geo. M. Wheeler ... , Volume 6: Botany 6, page 260. The specific epithet arizonica refers to Arizona, specimens from this state were used for the first description.

The species Pinus arizonica belongs to the sub-section Ponderosae from the section Trifoliae in the sub-genus Pinus within the genus Pinus .

There are three varieties of Pinus arizonica :

  • Pinus arizonica Engelm. var. arizonica : The mostly large trees reach a height of 30 to 35 meters. The needles usually grow in groups of three or four, rarely with five, they are stiff or somewhat soft, straight or slightly curved and twisted, usually 10 to 20 centimeters long, rarely from 8 to 23 centimeters with a diameter of usually 0.9 to 1 , 4 rarely up to 1.6 millimeters. The seed cones are open ovate to broadly ovate, often slightly curved and rarely from 4.5, usually 5 to 7 centimeters long with a diameter of 3.5 to 6 centimeters. The seeds are obliquely egg-shaped, slightly flattened, 4 to 6 millimeters long and 3 to 3.5 millimeters wide. The seed wing is obliquely egg-shaped, 12 to 15 millimeters long and 4 to 6 millimeters wide. The distribution area is in Arizona and New Mexico, in the Sierra Madre Occidental south to Durango and scattered in Coahuila, in the northeast of Zacatecas and in Nuevo León. The variety was also known as the subspecies Pinus ponderosa subsp. arizonica (Engelm.) E. Murray and as a variety Pinus ponderosa var. arizonica (Engelm.) Shaw assigned to the species Pinus ponderosa Douglas ex C.Lawson . These two names are considered synonyms .
  • Pinus arizonica var. Cooperi (CEBlanco) Farjon : Most large trees reach a stature height of 30 to 35 meters. The needles usually grow in groups of five, less often in groups of four or three, they are stiff or somewhat soft, often curved, usually 6 to 10 centimeters long, rarely from 5 to 12 centimeters with a diameter of 1 to 1.3 millimeters. The seed cones are open ovate to broadly ovate, often slightly curved and 5 to 10 rarely up to 12 centimeters long with a diameter of 4 to 6 centimeters. The seeds are obliquely egg-shaped, slightly flattened, 5 to 7 millimeters long and 4 to 5 millimeters wide. The seed wing is obliquely egg-shaped, 15 to 20 millimeters long and 6 to 8 millimeters wide. The distribution area is mainly in Durango, but there are also scattered occurrences further north in the Sierra Madre Occidental to Chihuahua and Sonora . The variety has also been described as a separate species Pinus cooperi C.E.Blanco . This name is considered a synonym.
  • Pinus arizonica var. Stormiae Martinez : The mostly medium-sized trees reach a height of 15 to 20 meters. The needles usually grow in threes or fours, rarely in groups of five, they are thick, coarse and stiff, mostly curved and twisted, 14 to 25 centimeters long with a diameter of 1.4 to 1.8 millimeters. The seed cones are open ovate to ovate-elongated, often curved and 5 to 10 rarely from 4.5 and up to 14 centimeters long with a diameter of 3.5 to 6 rarely up to 8 centimeters. The seeds are obliquely egg-shaped, slightly flattened, 5 to 6 millimeters long and 3.5 to 4 millimeters wide. The seed wing is obliquely egg-shaped, 12 to 16 millimeters long and 6 to 8 millimeters wide. The range is mainly in the south of Nuevo León with some other occurrences in the south of Coahuila, Zacatecas and possibly also in San Luis Potosí . The variety was also assigned as the variety Pinus ponderosa var. Stormiae (Martinez) Silba of the species Pinus ponderosa Douglas ex C.Lawson . This name is considered a synonym.

In the United States, Pinus arizonica hybridizes naturally with Pinus ponderosa var. Scopulorum and with Pinus engelmannii , in its range in Mexico possibly with other representatives of the subsection Ponderosae .

use

Pinus arizonica is an important supplier of wood in Mexico, where it has a similar importance to Pinus ponderosa in the United States. The wood is also used in a similar way; larger logs are used to make window frames, doors, stairs, floors and furniture. The wood is processed by many local and regional sawmills, and only a small part is exported. However, overexploitation has severely reduced stocks and in the short term no sustainable forestry can be established, leading to declining yields. The species is not used for horticulture, but representatives from the United States who have been classified as Pinus ponderosa could be used in parks.

swell

literature

  • Aljos Farjon: A Handbook of the World's Conifers . tape 2 . Brill, Leiden-Boston 2010, ISBN 90-04-17718-3 , pp. 621-624 .
  • James E. Eckenwalder: Conifers of the World. The Complete Reference . Timber Press, Portland, OR / London 2009, ISBN 978-0-88192-974-4 , pp. 410-411 .
  • Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 487 (reprint from 1996).

Individual evidence

  1. ↑ a b c d e f g h i Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 623
  2. ↑ a b c d e f James E. Eckenwalder: Conifers of the World , p. 410
  3. ↑ James E. Eckenwalder: Conifers of the World , p. 411
  4. ↑ Pinus arizonica in the endangered Red List species the IUCN 2012. Posted by: Conifer Specialist Group, 1998. Accessed June 6, 2013.
  5. ↑ Pinus arizonica at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed April 19, 2019.
  6. ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 621
  7. ^ Pinus arizonica in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 6, 2013.
  8. ↑ Christopher J. Earle: Pinus arizonica. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed June 2, 2013 .
  9. ↑ a b c Aljos Farjon: A Handbook of the World's Conifers , Volume 2, p. 624
  10. ↑ James E. Eckenwalder: Conifers of the World , pp. 410-411
  11. ^ Aljos Farjon: A Handbook of the World's Conifers , Volume 2, pp. 623-624

Web links

Commons : Pinus arizonica  - collection of images, videos and audio files
  • Vascular Plants of the Americas Pinus arizonica at Tropicos.org. In: 83 . Missouri Botanical Garden, St. Louis