| Pinus jeffreyi | |
|---|---|
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| A stand ofPinus jeffreyi growing on volcanic table lands south of Mono Lake, California | |
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.Ponderosae |
| Species: | P. jeffreyi |
| Binomial name | |
| Pinus jeffreyi | |
 | |
Pinus jeffreyi, also known asJeffrey pine,Jeffrey's pine,yellow pine[2] andblack pine,[3] is aNorth Americanpine tree. It is mainly found inCalifornia, but also in the westernmost part ofNevada, southwesternOregon, and northernBaja California.[4]: 4 It is named in honor of its botanist documenterJohn Jeffrey.
Pinus jeffreyi is a largeconiferous evergreen tree, reaching 25 to 40 meters (82 to 131 ft) tall, rarely up to 53 m (174 ft) tall, though smaller when growing at or neartree line.[5] Theleaves are needle-like, in bundles of three, stout,glaucous gray-green, 12 to 28 centimeters (4+3⁄4 to 11 in) long.[6] Thecones are12 to 30 cm (4+3⁄4 to11+3⁄4 in) long,[7][6] dark purple when immature, ripening pale brown, with thinly woody scales bearing a short, sharp inward-pointing barb. The brownish seeds are10 to 12 millimeters (3⁄8 to1⁄2 in) long, with a large wing,[6] measuring15 to 25 mm (5⁄8 to 1 in).
Pinus jeffreyi is closely related toPinus ponderosa (ponderosa pine) and is similar in appearance. One way to distinguish between them is by their cones. Each has barbs at the end of the scales. The sharpP. jeffreyi cone scale barbs point inward, so the cone feels smooth to the palm of one's hand when rubbed down the cone.Pinus ponderosa cone scale barbs point outward, so feel sharp and prickly to the palm of one's hands. The memory device of 'gentle Jeffrey' and 'prickly ponderosa' can be used to differentiate between the species. Another distinguishing characteristic is that the needles ofP. jeffreyi are glaucous, less bright green than those ofP. ponderosa, and by the stouter, heavier cones with larger seeds and inward-pointing barbs.[8]Pinus jeffreyi can be somewhat distinguished fromP. ponderosa by the relatively smaller scales of reddish-brown bark as compared to the larger plates of orangish ponderosa bark.[7]
The scent ofP. jeffreyi is variously described as reminiscent of vanilla, lemon, pineapple, violets, apple,[9] and, quite commonly, butterscotch.[10] This scent may be sampled by breaking off a shoot or some needles, or by simply smelling the resin's scent in between the plates of the bark. This scent is related to the very unusual composition of the resin, with thevolatile component made up almost entirely of puren-heptane. It is because of this peculiarity that the trees are sometimes known asgasoline trees. Easy availability of this hydrocarbon in pure form made it the basis of the modernoctane rating in the late 1920s.[11][12]
The largest specimen, by trunk volume, is the Eureka Valley Giant, in theStanislaus National Forest. Its trunk contains 129 m3 (4,600 cu ft) of wood, is 59 m (194 ft) tall, with a diameter of 2.5 m (8 ft 2 in).[13]
Pinus jeffreyi is named for its discoverer, Scottish botanistJohn Jeffrey, who encountered it in 1852 near Mount Shasta.[14]Pinus is Latin for pine.[15]
Pinus jeffreyi occurs from southwestOregon south through much ofCalifornia (mainly on theeastern side of theSierra Nevada), to northernBaja California in Mexico. It is a high-altitude species; in the north of its range, it grows widely at 1,500 to 2,100 m (4,900 to 6,900 ft) altitude, and at 1,800 to 2,900 m (5,900 to 9,500 ft) in the south of its range.[5]
Pinus jeffreyi is more stress tolerant thanP. ponderosa. At higher elevations, on poorer soils, in colder climates, and in drier climates,P. jeffreyi replacesP. ponderosa as the dominant tree.[4]Pinus jeffreyi is also tolerant ofserpentine soils and is often dominant in these conditions, even on dry sites at fairly low altitudes.[5]
Pinus jeffreyi can hybridize withP. ponderosa and theCoulter pine, however this occurrence is rare due to the fact that the pines release pollen at different times of the year.[7][16]
Mammals and birds collect the seeds.[6]
Pinus jeffreyi wood is similar to ponderosa pine wood, and is used for the same purposes. Crystallized sap ofP. jeffreyi has been eaten as candy.[14] The exceptional purity ofn-heptane distilled fromP. jeffreyi resin led ton-heptane being selected as the zero point on theoctane rating scale ofpetrol.
As it mainly consists of n-heptane,P. jeffreyi resin is a poor source ofturpentine.[17] BeforePinus jeffreyi 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,[18] now known to have been caused by the unwitting use of Jeffrey pine resin.
