Pinus edulis

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Pinus edulis
Pinus edulis

Pinus edulis

Systematics
Family : Pine family (Pinaceae)
Subfamily : Pinoideae
Genre : Pine ( Pinus )
Subgenus : Strobus
Section : Parrya
Type : Pinus edulis
Scientific name
Pinus edulis
Engelm.

Pinus edulis is a species of pine ( Pinus ). It isnative towestern North America . The species tolerates drought and produces large, edible seeds. Like the single-leaved pine ( Pinus monophylla ), this species belongs to the plant community of Pinyon pines . Pinus edulis is the state tree of the US state New Mexico .

description

Needles
Branch with cones
Cones with seeds
Seeds

Habitus

Pinus edulis is an evergreen tree that can grow to a height of around 15 meters, in exceptional cases up to 21 meters and a trunk diameter of 0.6 to 1.7 meters. The species usually forms a bushy crown . The flexible branches and young shoots are quite thick.

Needles

The pointed needles , dark green on the top and clearly blue-green on the underside, are between 2 and 4 centimeters long. They have no teeth whatsoever and are relatively coarse, quite thick and slightly curved inwards. Each needle has two, rarely one, resin channels in cross section . The needles are usually in pairs on short shoots . In some populations, up to 25% of the trees can be three-needle. Trees with only one needle per short shoot are very rare.

Flowers, cones and seeds

Pinus edulis is monoecious, has separate sexes ( monoecious ) and becomes manable at around 25 years of age . The planting of the cones begins in August to September and is completed in October. Flowering begins in May and pollination usually takes place in June. The male cones are 7 millimeters long and yellowish to reddish brown in color. The almost spherical cones need about 26 to 27 months from pollination to maturity . The ripe, light yellow and pale green tinted cones are between 3 and 6 inches long and 4 and 7 inches wide. They consist of 20 to 24 cone scales and sit on stems up to 3 millimeters long. The cones are often sticky from the resin and contain 20 to 40 seeds. The 10 to 15 millimeters large, light yellow to reddish brown colored and wingless seeds are edible. The thousand grain weight is around 239 grams. The seeds are mainly spread by birds ( ornithochory ). The Florida bush jay ( Aphelocoma coerulescens ), the naked- billed jay ( Gymnorhinus cyanocephalus ) and the pine jay ( Nucifrage columbiana ) play a major role .

bark

Branches and young trunks have a smooth, gray bark . Older trunks have a red-brown and irregularly torn bark. This bark becomes 2 to 3 centimeters thick. The bark of the twigs and young shoots is initially light orange-brown, later it becomes dark brown and gray.

Wood

The yellowish brown heartwood is surrounded by a narrow and almost white sapwood . The hard, brittle and very resinous wood is usually very tight. The kiln density is between 0.43 and 0.62 g / cm³.

Root system

If the soil structure permits, Pinus edulis forms a deep taproot system with far- reaching lateral roots. The taproot can penetrate to depths of up to 6.4 meters, but the majority of the roots can be found at depths of up to 50 centimeters. In northwestern Colorado the species forms ectomycorrhizae with Cenococcum geophilum , Rhizopogon ellenae and Rhizopogon pinyonensis . Endomycorrhizae have not yet been observed.

Chromosome number

The number of chromosomes is 2n = 24.

Distribution area

distribution and habitat

The distribution area of Pinus edulis is in the coastal southwest of the USA and the southern Rocky Mountains . It includes the US states of Oklahoma , Colorado , Wyoming , New Mexico, Texas , Arizona , California and Utah , and it extends a little way into northern Mexico . The total area of ​​the forests planted with Pinus edulis is around 14.9 million hectares.

It inhabits locations in semi- arid and dry subhumid regions. You can find them at altitudes of 900 to 3,200 meters. The temperatures fluctuate between +44 ° C in summer and -35 ° C in winter. The annual rainfall is between 250 and 700 mm. Soils of different thicknesses and structures are populated. The spectrum ranges from coarse gravel to compact clay soils . There are only minor demands on the pH value of the soil, but a pH value of 7 to 8 is considered optimal.

Depending on the location, Pinus edulis forms mixed stands with the sagebrush ( Artemisia tridentata ), with Artemisia nova , with Cercocarpus ledifolius , with Cercocarpus montanus , with Cowania mexicana , with Fallugia paradoxa , with Gutierrezia sarothrae , the alligator juniper ( Juniperus ), the seeded juniper ( Juniperus monosperma ), the Utah juniper ( Juniperus osteosperma ), the Rocky Mountain juniper ( Juniperus scopulorum ), with pinchotii Juniperus , the viol body ( Quercus gambelii ), with Quercus grisea , with Quercus turbinella with Purshia tridentata and with the three-lapping sumac ( Rhus trilobata ). Different types of rock pears ( Amelanchier ), ephedra ( Ephedra ), Opuntia ( Opuntia ), Yucca ( Yucca ), Chrysothamnus and Eriogonum occur with different frequency in Pinus edulis on inventories directly. The undergrowth is majority by Aster hirtifolius , the blue tuft wheatgrass ( Agropyron spicatum ), Agropyron smithii , Agropyron trachycaulum , the mosquito grass ( Bouteloua gracilis ), Bouteloua curtipendula , the downy brome ( Bromus tectorum ), Calochortus nuttallii , Chenopodium graveolens , the pyramids -Schillergras ( Koeleria pyramidata ) Hilaria jamesii , Hymenopappus filifolius , Muhlenbergia torreyi , Petra Doria pumila , the Indian rice grass ( Oryzopsis hymenoides ) Sitanion hystrix , Stipa comata as well as species of the genera Beardtongue ( Penstemon ) Arisitada , Gilia , Sphaeralcea and Sporobolus formed.

use

Due to the small dimensions and the poor trunk shape, the wood has no economic importance as construction timber . However, the species is often used as firewood and as a Christmas tree . The edible seeds are nutritious and tasty. They have long been consumed and traded. They were an important source of food for many Indian tribes . They are still harvested today and mostly eaten in roasted form. The amount used commercially each year is between 500,000 and 900,000 kilograms. Due to the low growth rate, the species is rarely used for afforestation . Especially in arid areas, however, it is a welcome element in landscape maintenance and for the preservation of water catchment areas .

Diseases and pests

Since the trees are mostly very gaps and a highly inflammable layer of bushes and herbs is usually missing, forest fires play a minor role. The most important pathogen is the dwarf mistletoe Arceuthobium divaricatum , which among other things forms witch brooms and weakens the tree and makes it more susceptible to other pathogens. The fungus Cronartium occidentale , the needle grates Coleosporium crowellii , Coleosporium jonesii and the needle chute pathogens Bifusella saccata and Elytroderma deformans are occasionally harmful. Root rot is honey mushrooms ( Armillaria ) and Verticicladiella wagenerii triggered. The two bark beetle species Ips confusus and Ips lecontei can kill stocks of several thousand hectares in certain years. In 2002 and 2003, there was widespread mass extinction of Pinus edulis in the US states of Arizona , Utah , New Mexico and Colorado ; Persistent drought and high temperatures weakened the trees so much that they were made to die by wooden beetles such as Ips confusus . Damage to the louse Matsucoccus acalyptus causes a needle browning. The beetle Conophthorus edulis and the moth Eucosma bobana are of economic importance as cone and seed pests . Coleotechnites edulicola mines the needles, but causes little damage. Neodiprion edulicola , as well as species of the genera Contarinia and Janetiella, form plant galls at the needle base which, however, apparently do not cause any damage to the tree. Tree prickers peel the bark from branches and trunks, which in extreme cases can lead to the death of the tree.

Systematics

Pinus edulis belongs to the subsection Cembroides in the section Parrya within the subgenus Strobus . In the last few years the geographic-genetic situation of Pinus edulis has been researched. Although there are intra-species differences, the species is not divided into geographical races . A synonym for the species is Pinus cembroides Zucc. var. edulis (Engelm.) Voss . Natural crosses take place with the single-leaved pine ( Pinus monophylla ) in western Utah, where the ranges of the two species overlap. In northwestern and central Arizona there are also natural crosses with a subspecies Pinus monophylla subsp. californiarum (DKBailey) Silba .

swell

Individual evidence

  1. ^ Tropicos. [1]
  2. ↑ a b c d e f Silvics of North America
  3. ↑ Wissenschaft-online.de Heat led to massive pine deaths

Web links

Commons : Pinus edulis  - album with pictures, videos and audio files