Alternate name: Yellow Pine
Family: Pinaceae, Pine view all from this family
Description Large, slow-growing, long-lived conifer. Site conditions affect form and size. Crown rounded, long or symmetrical. Lower branches large, droopy; upper branches smaller ascending. Trunk straight. Bark thick, furrowed with small scales. Needles in bundles of three, stout, glaucous gray-green, 12 to 23 cm. (4.7 to 9.1 in.) long. Cones are 12 to 24 cm. (4.7 to 9.4 in.) long, dark purple when immature, ripening pale brown, thin woody scales bearing a short, sharp inward-pointing barb. Seeds are 10 to 12 mm. (0.39 to 0.47 in.) long, with a large (15 to 25 mm. (0.59 to 0.98 in.) wing. Resin scented of vanilla, lemon, pineapple, violets, or apple.
Dimensions Height: 24-39 m. (80-130 ft.)
Diameter: 0.6-1.2 m (2-4 ft.), sometimes much larger.
Range Northwest, Southwest, California.
Discussion JJeffrey Pine wood is similar to Ponderosa Pine wood, and is used for the same purposes. The exceptional purity of n-heptane distilled from Jeffrey Pine resin led to n-heptane being selected as the zero point on the octane rating scale of petrol. As n-heptane is explosive when ignited, Jeffrey Pine resin cannot be used to make turpentine. Before Jeffrey Pine was distinguished from Ponderosa Pine as a distinct species in 1853, resin distillers operating in its range suffered a number of 'inexplicable' explosions during distillation, now known to have been caused by the unwitting use of Jeffrey Pine resin.