Knobcone pine

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Pinus attenuata
Knobcone pine
Knobcone pine cone
Conservation status
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Pinus
Subgenus: Pinus
Species: P. attenuata
Binomial name
Pinus attenuata
Lemmon

The knobcone pine, Pinus attenuata, (also called Pinus tuberculata[2]) is a tree that grows in mild climates on poor soils. It ranges from the mountains of southern Oregon to Baja California with the greatest concentration in northern California and the Oregon-California border.[3]

Description

The knobcone pine (Pinus attenuata) crown is usually conical with a straight trunk. It reaches heights of 8–24 metres (26–79 ft).[4] However, it can be a shrub on especially poor sites. It prefers dry rocky mountain soils. The bark is smooth, flaky and gray-brown when young, becoming dark gray-red-brown and shallowly furrowed into flat scaly ridges. The twigs are red-brown and often resinous.

The leaves are in fascicles of three,[5] needle-like, yellow-green, twisted, and 9–15 cm (about 3.5–6 in) long. The cones are 8–16 cm long and clustered in whorls of three to six on the branches. The scales end in a short stout prickle. The cones remain closed for many years until a fire opens them and allows reseeding. As a result, the cones may even become embedded in the trunk as the tree grows.

Ecology

Further information: Fire ecology

The knobcone pine (Pinus attenuata) forms nearly pure stands, however it may hybridize with bishop pine (Pinus muricata), and Monterey pine (Pinus radiata) on the coast.

In the western foothills of the Sierra Nevada, knobcone pine is often a co-dominant with blue oak (Quercus douglasii).[6]

References

  1. ↑ Conifer Specialist Group, 1998
  2. ↑ Chase, J. Smeaton (1911). Cone-bearing Trees of the California Mountains. Chicago: A. C. McClurg & Co. p. 99. LCCN 11004975. OCLC 3477527.  LCC QK495.C75 C4, with illustrations by Carl Eytel - Kurut, Gary F. (2009), "Carl Eytel: Southern California Desert Artist", California State Library Foundation, Bulletin No. 95, pp. 17-20 retrieved Nov. 13, 2011
  3. ↑ Moore, Gerry; Kershner, Bruce; Craig Tufts; Daniel Mathews; Gil Nelson; Spellenberg, Richard; Thieret, John W.; Terry Purinton; Block, Andrew (2008). National Wildlife Federation Field Guide to Trees of North America. New York: Sterling. p. 85. ISBN 1-4027-3875-7. 
  4. ↑ Gymnosperm Database, 2008
  5. ↑ eNature Field Guides, 2007
  6. ↑ C. Michael Hogan, 2008

Further reading

External links

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