[Wikipedia] Vanilla scent: The scent of Pinus jeffreyi is variously described as reminiscent of vanilla, lemon, pineapple, violets, apple,[7] and, quite commonly, butterscotch;[8] 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 the volatile component made up almost entirely of pure n-heptane.

[srs.fs.usda.gov] Taxonomy: Jeffrey pine (Pinus jeffreyi) was discovered in 1852 in the Shasta Valley of California by John Jeffrey, a Scottish botanical explorer. Partly overlapping ponderosa pine (Pinus ponderosa) in range and superficially resembling it, Jeffrey pine was first classified as a variety of ponderosa pine (28,45). These western yellow pines produce wood of identical structure and quality and are closely related taxonomically (10). Jeffrey pine is distinct chemically, ecologically, and physiologically and is readily distinguished from ponderosa pine on the basis of bark, leader, needle, bud, and cone morphology (23). (link added by Mary Ann Machi)