knobcone pine Pinaceae Pinus
attenuata Lemmon symbol: PIAT
Leaf: Evergreen needles, commonly 4 to 5 inches (but may be 3 to 7), borne in bundles of 3; yellow-green, slender, stiff, and sometimes twisted; persist for 4 to 5 years.
Flower: Species is monoecious; male cones are brownish purple in tight clusters; females small, reddish purple.
Fruit: Large woody cones (4 to 6 inches long); egg-shaped to conical but with a distinctly asymmetrical base, large swollen knobs on one side of the base; often grow in dense clusters of 3 to 6 and remain on the tree unopened until a fire occurs; sometimes completely overgrown by the branches and trunk; mature by late summer of their second year.
Twig: Moderately stout, reddish brown and often resinous.
Bark: Young bark is thin, flaky, and is gray-brown with an orange or red tinge; older bark is furrowed with flattened ridges and somewhat scaly; gray-red-brown.
Form: A small conifer (most often less than 50 feet tall and 12 inches in diameter); often with poor form and multiple, twisted tops.
Looks like: ponderosa pine - Jeffrey pine - Bishop pine - Monterey pine
Additional Range Information: Pinus attenuata is native to North America. Range may be expanded by planting. See states reporting knobcone pine.
External Links: USDAFS Additional Silvics - USDA Plants Database
All material © 2018 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson; Silvics reprinted from Ag Handbook 654