|Subgenus:||P. subg. Pinus|
|Section:||P. sect. Trifoliae|
|Subsection:||P. subsect. Australes|
The knobcone pine, Pinus attenuata (also called Pinus tuberculata), 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.
The knobcone pine (Pinus attenuata) crown is usually conical with a straight trunk. It reaches heights of 8–24 metres (26–79 ft). 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, 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.
- Farjon, A. (2013). "Pinus attenuata". IUCN Red List of Threatened Species. 2013: e.T42343A2974092. doi:10.2305/IUCN.UK.2013-1.RLTS.T42343A2974092.en.
- Chase, J. Smeaton (1911). "Pinus tuberculata, Also called P. attenuta (Knob-cone-pine, Scrub-pine)". Cone-bearing Trees of the California Mountains. Eytel, Carl (illustrations). Chicago: A.C. McClurg & Co. pp. 32–34. LCCN 11004975. OCLC 3477527.
- 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 978-1-4027-3875-3.
- Earle 2018.
- eNature Field Guides, 2007
- C. Michael Hogan, 2008
- Conifer Specialist Group (1998). "Pinus attenuata". IUCN Red List of Threatened Species. 1998. Retrieved 12 May 2006.CS1 maint: ref=harv (link)old-form url
- eNature Field Guides (2007) Knobcone Pine
- Earle, Christopher J., ed. (2018). "Pinus attenuata". The Gymnosperm Database.
- C. Michael Hogan (2008) Blue Oak: Quercus douglasii, GlobalTwitcher.com, ed. Nicklas Stromberg
- Elna S. Bakker (1971). An island called California. University of California press (1972). ISBN 0-520-02159-2
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