Knobcone pine

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]

Knobcone pine
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Pinus
Subgenus: P. subg. Pinus
Section: P. sect. Trifoliae
Subsection: P. subsect. Australes
Species:
P. attenuata
Binomial name
Pinus attenuata

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.

  • Leaves
  • male cones
  • Cones
  • Knobcone pine cone
  • Plant
  • Habitat

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. Farjon, A. (2013). "Pinus attenuata". IUCN Red List of Threatened Species. 2013: e.T42343A2974092. doi:10.2305/IUCN.UK.2013-1.RLTS.T42343A2974092.en.
  2. 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.
  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 978-1-4027-3875-3.
  4. Earle 2018.
  5. eNature Field Guides, 2007
  6. C. Michael Hogan, 2008

Further reading
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