| Knobcone pine | |
|---|---|
| |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| 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
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| Binomial name | |
| Pinus attenuata | |
| |
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 OregontoBaja California with the greatest concentration in northern California and the Oregon-California border.[3]
Individual specimens can live up to a century.[4] The crown is usually conical with a straight trunk. It reaches heights of 8–24 meters (26–79 feet),[5] but can be a shrub on especially poor sites. The bark is thin and smooth, flaky and gray-brown when young, becoming dark[4] gray-red-brown and shallowly furrowed into flat scaly ridges in age. The twigs are red-brown and often resinous. Its wood is knotty and of little interest for lumber.[4]
The leaves are in fascicles of three,[6] needle-like, yellow-green, twisted, and 9–15 centimeters (3+1⁄2–6 in) long. The cones are resin-sealed and irregularly shaped,[4] 8–16 cm (3+1⁄4–6+1⁄4 in) long and clustered in whorls of three to six on the branches. The scales end in a short stout prickle. Cones can sometimes be found attached to the trunk and larger branches.[4]
The knobcone pine can be found growing in the dry, rocky soils of southern Oregon and northern California, between 300 and 750 m (980 and 2,460 ft) above sea level.[4] It forms nearly pure stands, preferring to grow where there is no competition.[4]
On the coast, the knobcone pine may hybridize with bishop pine (Pinus muricata), and Monterey pine (Pinus radiata).
In the western foothills of the Sierra Nevada, knobcone pine is often a co-dominant with blue oak (Quercus douglasii).[7]
The species is susceptible to fire, but this melts the cone resin, releasing seeds for regrowth.[4] The species seems to be shade intolerant.[4]
| Pinus attenuata |
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